JP4841435B2 - Phased array antenna system with adjustable electrical tilt - Google Patents

Abstract

A phased array antenna system with adjustable electrical tilt includes an array 62 of antenna elements 621 to 6210. It has a splitter 44 dividing a radio frequency (RF) carrier signal into two signals between which a phase shifter 46 introduces a variable phase shift. Further splitters 52 and 54 divide the relatively phase shifted signals into two sets of five signals. Four of each of the sets of five signals are vectorially combined in a network of 180 degree hybrid couplers 601 to 604. This provides vector sum and difference components which together with the fifth members of the sets are fed to respective fixed phase shifters 56, 58 and 641 to 6410. The phase shifters 641 to 6410 provide signals which are appropriately phased for use as phased array drive signals for respective antenna elements 621 to 6210. Adjustment of the single phase shift provided by the variable phase shifter 46 changes the angle of electrical tilt of the entire antenna array 62.

Description

  The present invention relates to a phased array antenna system with adjustable electrical tilt. While it is suitable for use in many areas of telecommunications, particular applications have been found in cellular mobile radio networks, commonly referred to as mobile telephone networks. In particular, but not without limitation, the antenna system of the present invention can be applied to second generation (2G) mobile phone networks such as GSM systems and third generation (3G) mobile phone networks such as universal mobile phone systems (UMTS). Can be used in

  Cellular mobile radio network operators typically use their own base stations, each having at least one antenna. In cellular mobile radio networks, antennas are a key element in defining the effective range within which communication to a base station can be performed. Its coverage is typically divided into a number of overlapping cells, each associated with a respective antenna and base station. Cells are also generally divided into sectors to increase the coverage of communications.

  Each sector's antenna is connected to a base station for wireless communication with all mobile radio receivers in that sector. Base stations are usually interconnected by other means of communication such as point-to-point radio links or fixed landlines, and mobile radio receivers throughout the cell coverage area are connected to each other as well as outside the cellular mobile radio network. To communicate with the public telephone network.

  Cellular mobile radio networks that use phased array antennas are known, and such antennas comprise an array of (typically 8 or more) individual antenna elements, such as dipoles or patches. The antenna has a radiation pattern consisting of a main lobe and side lobes. The center of the main lobe is the direction of the maximum sensitivity of the antenna, that is, the direction of the main radiation beam. If the signal received by the antenna element is delayed by a delay that varies linearly with distance from the edge of the array, the main radiation beam of the antenna is directed in the direction of increasing delay. This is a well-known characteristic of a tuned array antenna. The central angle between the main radiation beams corresponding to zero and non-zero delay variations, i.e., the angle of pointing, depends on the rate of change in delay with distance between the arrays.

  By changing the signal phase, the delay can be implemented equivalently, thus resulting in a mathematical phase adjustment array. Therefore, the main beam of the antenna pattern can be changed by adjusting the phase relationship between signals applied to different antenna elements. This allows the beam to be directed to change the effective range of the antenna.

  Operators of phased array antennas in cellular mobile radio networks have a desire to adjust their antenna's vertical radiation pattern, ie, the cross-section of the pattern in the vertical plane. This is essential for changing the vertical angle of the main beam of the antenna, also known as “tilt”, in order to adjust the effective range of the antenna. For example, such adjustments may be required to compensate for changes in the cellular network structure or the number of base stations or antennas. The adjustment of the antenna angle of tilt is known both mechanically and electrically and is known individually or in combination.

  By moving the antenna elements, or their housing (radar dome), the antenna angle of the tilt can be adjusted mechanically, which is referred to as adjusting the angle of the “mechanical tilt”. As described above, the tilt antenna angle can be changed by changing the time delay or phase of the signal applied to or received from each antenna array element (or group of elements) without physical movement. Can be electrically adjusted, which is referred to as adjusting the angle of the “electrical tilt”.

When used in cellular mobile radio networks, the phased array antenna vertical radiation pattern (VRP) has a number of important requirements.
1. High main lobe (or aiming) gain,
2. First upper sidelobe level that is low enough to avoid interference to mobiles using base stations in different cells or networks
3. First lower sidelobe level high enough to allow communication in the very vicinity of the antenna

  These requirements contradict each other. For example, as the aiming gain increases, the sidelobe level will increase. Based on the aiming level, a first upper sidelobe level of -18 dB has been found to provide a reasonable compromise in overall system performance.

  The effect of adjusting either the mechanical tilt angle or the electrical tilt angle is to change the position of the aim so that the aim is either above or below the horizontal plane, which is effective for the antenna. Change the range.

  It is desirable to be able to change both the mechanical and electrical tilt of the antenna of a cellular radio base station, and these forms of tilt can affect the ground coverage of the antenna and also to other antennas in the immediate vicinity of the base station. This allows for maximum flexibility in cell or sector coverage optimization. Furthermore, the operating efficiency is improved when the electrical tilt angle can be adjusted away from the antenna assembly. While the angle of the mechanical tilt of the antenna can be adjusted by changing the position of the radar dome, changing the angle of the electrical tilt requires additional electronic circuitry that increases the cost and complexity of the antenna. To do. Furthermore, when sharing a single antenna among multiple operators, it is preferable to provide each operator with a separate electrical tilt angle.

  The need for a separate angle of electrical tilt from a shared antenna has not been met before, resulting in a compromise in system performance. If the gain decreases as a result of the approach employed to change the electrical tilt angle, further degradation in system performance may also occur.

RCJohnson, Antenna Engineers Handbook, 3 ^rd Ed 1993, McGraw Hill, ISBN 0-07-032381-X, Ch 20, Figure 20-2 shows how to adjust the electrical tilt angle of a phased array antenna locally or remotely A method is disclosed. In this method, a carrier signal of a radio frequency (RF) transmitter is sent to an antenna and delivered to the radiating element of the antenna. Each antenna element is associated with a variable phase shifter so that the signal phase can be adjusted as a function of the distance between the antennas to change the angle of the electrical tilt of the antenna. The distribution of power when not tilted is adapted to set the sidelobe level and aiming gain. Optimal control of the tilt angle is obtained when the phase plane is controlled for all tilt angles so that the sidelobe level does not increase over the entire tilt range. If necessary, the electrical tilt angle can be remotely adjusted by controlling the position of the phase shifter using a servomechanism.

  The antenna of this prior art method has a number of disadvantages. For each antenna element, a variable phase shifter is required. Due to the number of such phase shifters required, the cost of the antenna is high. The cost can be reduced by using a single common delay device or phase shifter for a group of antenna elements rather than element by element, but this increases the level of sidelobes. For example, see published international patent application WO 03/036756 and Japanese patent application JP20011211025 A.

  Although the delay device's mechanical coupling can be used to adjust the delay, it is difficult to do this correctly. In addition, mechanical linkages and gears result in non-optimal distribution of delay. When the antenna is tilted downward, the level of the upper sidelobe increases, thus providing what can be a source of interference for mobiles using other base stations. When the antenna is shared by multiple operators, it is preferred that the operators have a common angle of electrical tilt rather than different angles. After all, when using antennas in communication systems with uplink and downlink at different frequencies (frequency division duplex system), the angle of electrical tilt in transmission mode due to the frequency dependent nature of the signal processing components Is different from the electric tilt angle in the reception mode.

  International Patent Applications Nos. PCT / GB2002 / 004166 and PCT / GB2002 / 004930 are based on the difference in phase between a pair of signal supplies connected to an antenna, and the angle of the electrical tilt of the antenna can be locally or remotely. Explain the adjustment.

  It is an object of the present invention to provide an alternative form of phased array antenna system.

The present invention provides a phased array antenna system having an adjustable electrical tilt and comprising an array of antenna elements, the system comprising:
a) a variable phase shifter to provide a variable relative phase shift between the first and second RF signals;
b) a splitting device for splitting the phase-shifted first and second signals into component signals; and
c) form a vector combination of the component signals so that the electrical tilt angle of the array can be adjusted in response to changes in the variable relative phase shift caused by the variable phase shifter. A signal combining network for providing a respective drive signal for each individual antenna element with an appropriate phase adjustment to the drive signals.

  The present invention uses only one signal variable phase shifter to adjust the electrical tilt in the entire array rather than one variable phase shifter per antenna element or group of antenna elements as in the prior art. It offers the advantage that it is possible. If one or more further phase shifters are used, an extended range of electrical tilt can be obtained.

  The antenna system can have an odd number of antennas. The variable phase shifter may be a first variable phase shifter, and the system is configured to shift a component signal phase shifted by the first variable phase shifter. The signal coupling and phase shifting network, including a variable phase shifter, wherein the second variable phase shifter is either directly or via one or more splitter / variable phase shifter combinations. Provides additional component signal output for

  The variable phase shifter may be one of a plurality of variable phase shifters, the signal phase shift and coupling network, some of which pass through all the variable phase shifters, some of which are all An antenna element drive signal is generated from a component signal that does not pass through the variable phase shifter.

  The splitting device can be arranged to split a component signal into further component signals for input to the signal phase shift and coupling network. The signal phase shift and combination network can use a phase shifter and a hybrid combiner (hybrid) to phase and vector combine the component signals. The hybrid can be a 180 ° hybrid and is also known as a sum and difference hybrid. The hybrid can be configured as a ring hybrid, each with a circumference of (n + 1/2) λ and the input and output ports separated by λ / 4, where n is an integer and λ is , The wavelength of the RF signal in which each ring hybrid is composed of its components. Each hybrid input and output port matches the system impedance.

  The hybrid for vector combining the component signals will be designed to convert the input signals I1 and I2 into vector sums and differences other than (I1 + I2) and (I1-I2).

  The splitting device, variable phase shifter, and signal phase shift and coupling network can be co-located with an antenna array to form an antenna assembly, the assembly being from a remote signal source. With a single RF input power feeder. Instead, the splitting device can include first, second, and third splitters, the first splitter being separated from the second and third splitters and the variable phase shifter. And the signal phase and coupling network, and the antenna array are co-located as an antenna assembly, and the assembly is disposed with the first splitter and a variable phase shifter. With dual RF input power feeder from remote signal source.

  The variable phase shifter may be a first variable phase shifter connected in the transmission channel, and the system includes a second variable phase shifter connected in the receive channel. There will be similar transmit and receive channels that provide a fixed phase shift rather than a variable phase shift. The signal phase shifting and combining network then generates an antenna element drive signal in response to the signal in the transmission channel and generates a reception channel signal from the signal generated at the antenna element operating in the reception mode. Arranged to operate in both modes. At that time, the angle of electric tilt can be adjusted independently in each mode.

  The variable phase shifter may be one of a plurality of variable phase shifters associated with each operator, and the system outputs a signal after phase shifting in each variable phase shifter. Including a filtering and combining device for routing to a common signal supply device, said common signal supply device antenna and a signal containing contributions from both operators, with the electrical tilt being adjustable independently Connected to a signal coupling and phase shift network. The plurality of variable phase shifters can comprise a respective pair of variable phase shifters associated with each operator, and the system is capable of independently adjusting the electrical tilt in each mode; It will have components with both forward and reverse signal processing capabilities to operate in transmit and receive modes.

As a further aspect, the present invention provides a method for adjusting the electrical tilt of a phased array antenna system including an array of antenna elements, the method comprising:
a) providing a variable relative phase shift between the first RF signal and the second RF signal;
b) separating the relative phase-shifted first and second signals into component signals; and
c) The component signals are vector combined and relative phase shifted so that the electrical tilt angle of the array can be adjusted in response to changes in the variable relative phase shift. Provide a drive signal for each individual antenna with phase adjustment.

  The array can have an odd number of antenna elements.

  The method can include generating at least one component signal that undergoes phase shifting in a plurality of variable phase shifters. The variable phase shifters can be interlocked, and the method includes a component signal that passes through all variable phase shifters, some of which do not pass through all variable phase shifters, and an antenna element drive signal. Creating a step.

  The method may include dividing the component signal into further component signals for input to the signal phase shift and combining network. It can use phase shifters and hybrids to phase and vector combine the component signals. The hybrid can be a 180 ° hybrid. They can be ring hybrids whose circumference is (n + 1/2) λ and whose input and output ports are separated by λ / 4, where n is an integer and λ is its component It is the wavelength of the RF signal that each ring hybrid uses. The splitting device can also include such a ring hybrid, where one port of each hybrid is terminated with a resistor whose value is equal to the system impedance to form a matched load.

  The hybrid for vector combination of the component signals can be designed to convert the input signals I1 and I2 into vector sums and differences other than (I1 + I2) and (I1-I2).

  The method provides a single RF input signal from a remote signal source for splitting, variable phase shifting, and vector combining in a network co-located with the antenna array to form an antenna assembly. , Can be included. Instead, the method supplies two RF input signals with variable phase relative to each other from a remote signal source to the antenna assembly and splits the signal in a network co-located with the antenna array. , Phase shifting, and combining steps. It can use transmit and receive channels for operation in both transmit and receive modes, generate antenna element drive signals in response to signals in the transmit channels, and operate in receive mode A receive channel signal is generated from the signal generated at the element.

The variable phase shifter may be one of a plurality of variable phase shifters associated with each operator, and the method includes the following steps.
a) after phase shifting in each variable phase shifter, filters and combines the signals and sends them to the splitting device and the common signal supply device connected to the signal combining and phase shifting network;
b) providing a signal including contributions from both operators to the antenna; and
c) Adjust the electrical tilt associated with each operator independently.

  The plurality of variable phase shifters may comprise a respective pair of variable phase shifters associated with each operator. The method uses components having both forward and reverse signal processing capabilities, and the method operates in transmit and receive modes with electrical tilt adjustable independently in each mode. Steps.

  In order that the present invention may be more fully understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings.

(Detailed explanation)
All the examples shown use connection points where the source impedance is equal to the respective load impedance to form a “matched” system. The matching system maximizes the power transmitted from the signal source to the load and avoids signal reflection. When a signal line is terminated with a resistor (see, eg, FIG. 6), the value of that resistor is equal to the system impedance to form an anti-reflection termination.

  Referring to FIG. 1, vertical radiation patterns (VRP) 10a and 10b of an antenna 12, which is a phased array of individual antenna elements (not shown), are shown. The antenna 12 is a plane, has a center 14 and extends in the vertical direction in the plane of the drawing. VRP 10a and 10b correspond to zero and non-zero variations in antenna element signal delay or phase with distance between antennas 12, respectively. They have a respective main lobe 16a, 16b with a centerline or "sighting" 18a, 18b, a first upper side lobe 20a, 20b, and a first lower side lobe 22a, 22b, where 18c Indicates the aiming direction when the delay variation is zero for comparison with the non-zero equivalent 18b. For example, when referred to without the subscript a or b, such as the side lobe 20, any associated pair of the elements is referred to indistinctly. VRP 10b is tilted (downward as shown) relative to VRP 10a, ie, the angle between main beam centerlines 18b and 18c having a magnitude that depends on the rate at which the delay varies with the distance between antennas 12, That is, there is a tilt angle.

  VRP must satisfy a number of conditions. a) high aiming gain, b) the first upper sidelobe 20 must be at a low enough level to avoid causing interference to mobiles using other cells, and c) below the first The side side lobes 22 must be sufficient to allow communication very close to the antenna.

Those requirements contradict each other. For example, maximizing the aiming gain will increase the side lobes 20,22. For the aiming level (length of main beam 16)
A first upper sidelobe level of -18 dB has been found to provide a reasonable compromise in overall system performance. By reducing the effective aperture of the antenna, the aiming gain decreases in proportion to the cosine of the tilt angle. Depending on how much the tilt angle changes, there will be a further reduction in aiming gain.

  The effect of adjusting either the mechanical tilt angle or the electrical tilt angle is to change the aim position so that the aim is either above or below the horizontal plane, thereby reducing the effective range of the antenna. To increase or decrease. Each of the mechanical tilt and electrical tilt has a separate effect on the shape and area of the ground coverage, and also has a separate effect on other antennas in both the very near and adjacent cells, For maximum flexibility of use, the cellular radio base station preferably has both mechanical and electrical tilt available. It is also convenient if the electrical tilt of the antenna can be adjusted away from the antenna. Furthermore, when sharing a single antenna among multiple operators, it is preferable to provide individual electrical tilt angles for each operator.

  Referring now to FIG. 2, a prior art phased array antenna system 30 is shown in which the electrical tilt angle is adjustable. System 30 includes an input 32 for a radio frequency (RF) transmitter carrier signal that is connected to a power distribution network 34. The network 34 is connected to each of the phase-adjusted array antenna systems 30 via phase shifters Phi.E0, Phi.E1L to Phi.E [n] L, and Phi.E1U to Phi.E [n] U, respectively. Connected to the radiating antenna elements E0, E1L to E [n] L, and E1U to E [n] U. Here, the subscripts U and L indicate the upper side and the lower side, respectively, n defining the phase adjustment array size is an arbitrary positive integer larger than 2, and a dotted line such as 36 is any It shows that the relevant elements can be replicated as required for the desired array size.

  The phased array antenna system 30 operates as follows. An RF transmitter carrier signal is provided to power distribution network 34 via input 32. Network 34 divides this signal between phase shifters Phi.E0, Phi.E1L-Phi.E [n] L and Phi.E1U-Phi.E [n] U (not necessarily equal) The phase shifter phase shifts the received signal and sends the resulting phase shifted signal to the respective associated antenna element E0, E1L-E [n] L, E1U-E [n] U. The phase shift and signal amplitude for each element is selected to select the appropriate electrical tilt angle. When the tilt angle is zero, the distribution of power by the network 34 is selected to set the sidelobe level and aiming gain appropriately. Optimal control of the tilt angle is obtained when controlling the phase plane for all angles of tilt so that the sidelobe level does not increase significantly over the entire tilt range. If necessary, the electric tilt can be controlled by controlling the phase shifters Phi.E0, Phi.E1L to Phi.E [n] L and Phi.E1U to Phi.E [n] U using a servomechanism. Can be remotely adjusted and it can be mechanically actuated.

The prior art phased array antenna system 30 has a number of disadvantages as follows.
a) Each phase shifter is required for each antenna element or element group.
b) The cost of the antenna is high due to the number of required phase shifters.
c) Cost savings by adding a phase shifter to the group of elements increases the level of side lobes.
d) Mechanical coupling and gears are used that are difficult to mechanically couple phase shifters to set the delay correctly and result in a non-optimal delay scheme.
e) When the antenna is tilted downward, the level of the upper side lobe increases, bringing to mobiles that use other cells what could be a source of interference.
f) If the antenna is shared by different operators, all must use the same angle of electrical tilt.
g) In systems with uplink and downlink of different frequencies (frequency division duplex system), the electrical tilt angle in transmission is different from the electrical tilt angle in reception.

Referring now to FIG. 3, there is shown a phased array antenna system 40 of the present invention having an adjustable electrical tilt angle. System 40, in the field called "level", including functional region 40 _{1-40 5} such as shown between dashed pairs, where five consecutive as 41. It has an input 42 for the RF carrier transmit signal. Input 42 is connected as an input to power splitter 44 and provides two output signals with amplitudes V1A, V1B, which are connected to variable phase shifter 46 and first fixed phase shifter 48, respectively. Input signal. Phase shifters 46 and 48 can be considered equivalently as time delays. These phase shifters provide respective output signals V2B and V2A to two power splitters 52 and 54, respectively. Power splitters 52 and 54 have n outputs such as 52a and 54a, respectively. Where n is a positive integer equal to 2 or more and the dotted outputs 52b and 54b can be replicated in any case as required for any desired phased array size. Shows the possible output.

The outputs of power splitters such as 52a and 54a provide output signals with amplitudes Va1 to Va [n] and Vb1 to Vb [n] (shown without the letter V), respectively. As will be described in more detail later, some of these output signals will have amplitudes equal to others, and some will have amplitudes not equal to others. In one embodiment (described) with 10 antenna elements (n = 5), Va1 = Va2 = Va3, Vb3 = Vb4 = Vb5, Va4 = Vb2 and Va5 = Vb1. These output signals are sent to the phase shift and coupling level 40 _4, the level 40 _4, the second and third phase shifters 56 and 58, and, a vector combination network, collectively indicated at 60 Including. Later, describing the level 40 ₄ in more detail. Level 40 ₄ provides drive signals to equally spaced antenna elements 62 ₁ -62 _n of phase adjustment array 62 via respective fixed phase shifters 64 ₁ -64 _n . Here, as before, n is any positive integer equal to or greater than 2, but equal to the value of n in the power splitters 52 and 54, and the size of the phase adjustment array is 2n Antenna element. Internal antenna elements 62 ₂ and 62 ₃ are shown in dotted lines, indicating that they can be replicated as required for any desired phased array size.

The phased array antenna system 40 operates as follows. The RF transmitter carrier signal is sent via input 42 to power splitter 44 (single feeder), where the RF transmitter carrier signal is the signals V1A and V1B (equal power in this example). It is divided into. Signals V1A and V1B are sent to variable and fixed phase shifters 46 and 48, respectively. The variable phase shifter 46 adds an operator selectable phase shift, or time delay, where the applied phase shift frequency controls the electrical tilt angle of the entire phase adjustment array 62, such as the antenna element 62 ₁ To do. The fixed phase shifter 48 is not essential, but is convenient. It adds a fixed phase shift that is conveniently selected to be half the maximum phase shift Φ _M that can be added by the variable phase shifter 46. This allows V1A to be variable in phase within the range of -Φ _M / 2 to + Φ _M / 2 relative to V1B, and these signals after phase shift are phase shifter 46 and V2B and V2A are called after output from 48.

Each of the power splitters 52 and 54 divides the signal V2B or V2A into respective sets of n output signals Vb1 to Vb [n] or Va1 to Va [n], where the power of each signal in each set Vb1 etc. or Va1 etc. are not necessarily equal to the power of other signals in the set. Set Va1 like and Vb1 etc. throughout the signal power variation in the case of different numbers of such antenna elements 62 ₁ in the array 62, different.

One of the set of output signals Vb1~Vb [n] via the second phase shifter 56 is fed to a respective fixed antenna phase shifter 64 ₃ Similarly, a set of output signals Va1~ one of the va [n] via the third phase shifter 58 and sent to another antenna phase shifter 64 _8. Second and third phase shifters 56 and 58 provide an embedded phase shift to compensate for the phase shift provided by the coupling network 60. Other signals within the set Vb1~Vb [n] and Va1~Va [n], in the network 60, is coupled with a two pair, via a phase shifter 64 _1, etc., each of the antenna elements 62 Generates a vector addition combined signal to drive ₁ etc. The fixed phase shifter 64 _1, etc. imposes different fixed phase shifts between the various antenna elements 62 _1, etc., depending on the element geometry throughout the array 62. When variable phase shifter 46 imposes a zero phase difference between signals V1A and V1B, this sets the zero reference direction (18a and 18b in FIG. 1) for the aim of array 62. Antenna phase shifters 64 ₁ etc. are not essential, but they can be used to: a) correctly harmonize the phase shift caused by the tilt process, b) optimize sidelobe suppression over the entire tilt range, and c) They are preferred because they can provide an electrical tilt of any fixed angle.

  The angle of electrical tilt of the array 60 is simply variable by using a variable phase shifter 46, which is one variable phase shifter. This is comparable to the prior art requirement of having multiple variable phase shifters, one for every antenna element or subgroup of antenna elements. When the phase difference introduced by the variable phase shifter 46 is positive with respect to the fixed phase shift 48, the antenna tilts in one direction, and when the phase difference is negative with respect to the fixed phase shift 48, The antenna tilts in the opposite direction.

If there are multiple users, each user will have a respective phased array antenna system 40. Instead, if users are required to share a common antenna, each user has a respective set of levels 40 ₁ and 40 ₂ in FIG. 3 while retaining the individual electrical tilt capability. Will. Further, a combined network consisting of levels 40 ₃ , 40 ₄ , and 40 ₅ may combine signals originating from splitters 44 and multiple sets of phase shifters or delays 46 and 48 for transmission to antenna array 62. ,Desired. Published international patent application WO 03/043127 A3 describes sharing in this way, it uses antennas with multiple subgroups of antenna elements, and each antenna element in the subgroup Have the same phase of the element drive signal. In the antenna system 40, all of the antenna elements 62 ₁ -62 _n have different phases of the element drive signals, as required to improve the performance of the phased array.

  It can be shown that the antenna system 40 has good sidelobe suppression that is maintained throughout its electrical tilt range. The antenna system 40 can be implemented at a lower cost than modern designs that provide similar levels of performance. A single variable delay device can be used to remotely adjust its electrical tilt, which allows each operator to share an antenna while simultaneously providing a separate electrical tilt angle for each operator To. As will be described later, by changing the antenna system 40 to include various paths for transmission and reception, and a phase shifter, the electrical tilt angle in the transmission mode can be The tilt angle can be either the same as or different from the tilt angle.

Referring now to FIG. 4, there is shown a portion 70 of an implementation of the present invention for a phased array 62 of _ten elements 62 ₁ -62 ₁₀ . Parts equivalent to those described above are given the same reference numerals. FIG. 4 corresponds to the parts 40 ₃ to 40 ₅ of FIG. 3, where the splitters 52 and 54 are shown exchanged in position. Splitters 52 and 54 receive input signals V2B and V2A, respectively, which are equal in power but variable in relative phase. Splitters 52 and 54 each divide their respective inputs into five signals, three of which have the same amplitude (A or B) and the other two have their amplitudes of 0.32 and 0.73 (A or B 0.32 or 0.73).

Eight of the ten signals from splitters 52 and 54 are sent to _four vector combining devices 60 ₁ -604. Each of these devices has two input terminals denoted I1 and I2 and two output terminals denoted S and D for sum and difference respectively (180 ° hybrid marked H) It is. Reference symbols I1 and I2 will also be used for convenience to indicate signals at their terminals. As shown in the terminal display, upon receipt of input signals I1 and I2, each of the hybrid 60 _through 603 _4, the S and D, produces two output signals is the vector sum and difference of its respective input signal . Table 1 below, the amplitude of the input signal received at the hybrid 60 _through 603 _4, and shows the output signal in the form of immediately generated vector, which in any case, any Expressed in terms of values A and B.
table 1

Table 2 below, splitters 52 and 54, and an output signal generated by the hybrid 60 _through 603 _4, shows the antenna elements via the antenna phase shifter (PS) 64 ₁ ~64 _10.
Table 2

One signal A or B from each splitter 52 or 54 is not transmitted to the antenna phase shifter 64 ₃ or 64 ₈ via the hybrid, phase shift instead, [Phi via the phase shifter 56 or 58 It was added, which is equal to the phase shift imposed by one of the hybrids 60 ₁ to 60 _4, and to compensate for it. This is known as “padding”. The fixed phase shifter pairs 56/64 ₃ and 58/64 ₈ could each be implemented as a single phase shift. In FIGS. 3 and 4, the input splitter 44 in FIG. 3 will provide (optionally) unequal power splitting so that the signal amplitudes V2A and V2B are different. Furthermore, (as described) hybrid 60 ₁ to 60 ₄ to provide a sum and difference vectors I1 + I2, and I1-I2 of, contain all or part of the functions of (optionally) splitters 52 and 54 You can also. That is, instead, the inputs I1 and I2 are converted into vector sums and differences other than I1 + I2 and I1-I2, such as the sum xI1 + yI2 when x and y are different numerical values. , it is possible to design a hybrid 60 ₁ to 60 _4. This total output power + hybrid losses must remain equal to total power input to the hybrid 60 _through 603 _4, subject to the constraint that. Furthermore, 180 ° hybrid 60 ₁ to 60 instead of _4, other phase shift can also be used hybrid give (e.g., 60 °, 90 °, or 120 °) to.

Referring now also to FIG. 5, a vector diagram is shown for antenna system 70 when the phase difference between signals V2A and V2B (having the same phase as A and B, respectively) is 90 °. This 90 ° is, in this example, the angle at which the phase plane across the antenna element is optimized. All vector sums and differences in FIG. 5 (i.e. all vectors except A and B) should actually be multiplied by 2-1 ^{/ 2} or 0.707, as shown in Tables 1 and 2, For example, A + 0.73B should be 0.707 (A + 0.73B). However, this multiplicative constant is simply a conversion factor and is omitted from the drawing to reduce complexity.

By specifying the values of A and B in Tables 1 and 2 at a 90 ° phase difference, the antenna system 70 is optimized, ie, at a 90 ° phase difference, the antenna system 70 has two electrical tilts. With a substantially linear phase plane throughout the antenna element and equal phase planes at the average tilt angle. Radial arrows, such as 80, terminating at 82 ₁ -82 ₁₀ indicate the magnitude and phase angle when the phased array drive signal appears at antenna elements 62 ₁ -62 ₁₀ respectively. An oblique arrow such as 84 indicates a radial vector offset from the radial vector A or B (eg, 0.73b or 0.32a). In the drawing, the two arrows 84a and 84b labeled + 0.73B and + 0.73A are treated as including the adjacent arrow 84 labeled + 0.32B and + 0.32A, and therefore, respectively. Extend and return to radial vectors A and B.

Bidirectional arrows such as 86 indicates the phase difference between the radius vector adjacent, the phase difference between the signals of the outermost pair 62 _{1/62 2} and 62 _{9/62 10} antenna elements in a 22 °, a 18 ° between all other pairs 62 _{2/62 3} to 62 _{8/62 9.} The difference between 18 ° and 22 ° is small in the context of a phased array, and therefore for practical purposes, adjacent antenna element pairs 62 _i / 62 _{i + 1} (i = 1˜ The phase difference between 9) is substantially constant and the phase variation across the array 62 is substantially a linear function of the position in the array as required for normal phased array operation. To do.

  As stated, FIG. 5 represents the situation at the 90 ° phase difference between signals A and B or V2A and V2B. The zero phase difference corresponds to the average angle of tilt, and the positive and negative phase differences correspond to the positive and negative angles of the antenna tilt.

Referring now to FIG. 6, there is shown a portion of the antenna system 100 of the present invention that includes an odd number of antenna elements, 11 in this example. System 100 is equivalent to example 70 with the addition of a small number of components, and the description that follows will focus on that difference. Parts equivalent to those previously described are given the same reference numbers. System 100 is differential output D of the hybrid 60 ₁ and 60 ₄ are not connected to the phase shifter 64 _{1-64 10,} instead, each in that they are connected to two-way splitters 102 and 104, before This is different from the system described in. These splitters, the signal from the hybrid 60 _through 603 _4, divided into each of the amplitude ratio c1 / c2, and d1 / d2, is c1 and d1 of these to drive the antenna elements 62 ₁ and 62 ₁₀ Sent to phase shifters 64 ₁ -64 ₁₀ for use in the future. C2 and d2 in the ratio are fed to I1 and I2 inputs of the fifth hybrid 60 ₅ additional same form as the hybrid 60 ₁ and 60 _4. Fifth hybrid 60 ₅ of the sum output S is terminated in a matched load 106, and, via a phase shifter 108, and an antenna phase shifter 64 ₀ [Phi-90 °, the additional antenna located at the center having a difference output D which is connected to the element 62 _0. In Figure 5, all antenna elements, the distance being equally spaced L, that the introduction of the central antenna element 62 _0, the elements 62 ₅ and 62 ₆ from L / 2 to the central antenna element 62 ₀ is adjacent (This is as shown in the drawing, but for the sake of convenience, the interval is shown larger than the actual case). However, such an L / 2 interval is not essential.

The actual effect of the modification of FIG. 6 on the antenna array 62 is that the elements 62 ₁ and 62 ₁₀ have their drive signals reduced to d1 (B-0.73A) and c1 (A-0.73B), and an additional central element 62 ₀ Has a drive signal d2 (B-0.73A) -c2 (A-0.73B).

It can be shown that the antenna system 100 has an asymmetrical vertical radiation pattern when tilted downward as compared to when tilted upward. There is an increase in signal power delivered to the end antenna elements 62 ₁ and 62 ₁₀ when the antenna array 62 is electrically tilted either upward or downward. Theoretically, when the drive signal variation (amplitude taper) across the array remains substantially constant throughout the antenna tilt range, the sidelobe level will be optimally controlled. A number of approaches can be used to offset the effect on the resulting sidelobe due to the increased power in the end antenna elements 62 ₁ and 62 ₁₀ when tilted.
1. An attenuator can be inserted in series with the end antenna elements 62 ₁ and 62 ₁₀ .
2. Two additional elements can be added to the antenna to split the end antenna elements 62 ₁ and 62 ₁₀ into two each.
3. A further hybrid can be used to transfer power, in part, from the end antennas 62 ₁ and 62 ₁₀ to an element near the center of the antenna. as well as,
4. As actually shown in FIG. 6, with a part of power from the antenna elements 62 ₁ and 62 ₁₀ at the end, it is possible to drive the central element 62 _0.

The antenna system 100 provides the following advantages.
1. When the antenna array 62 is electrically tilted, the level of the side lobe of the antenna is lowered.
2. When the electrical tilt is past the intermediate value, the central element 62 ₀ phase of conveying or drive signal is changed 180 °, further, when tilted downwards, the level of the upper side lobe decreases.
3. The effect of lowering the upper sidelobe level when the antenna is tilted downward reduces the interference caused to mobiles that use channels other than those assigned to that antenna system 100. It is.

Referring now to FIG. 7, a portion of an implementation 120 of the present invention is shown for a phased array 122 of _twelve elements 122 ₁ -122 ₁₂ . The first and second splitters 124 ₁ and 124 ₂ receive input signals indicated by vectors A and B, respectively, in which the power is equal but the relative phase is variable. Splitters 124 ₁ and 124 _2, respectively, to implement division into three ratios a1 / a2 / a3, and b1 / b2 / b3. That is, the signal a1A, a2A, and a3A are output from the splitter 124 _1, the signal ratio b1B, B2B, and b3B is outputted from the splitter 124 _2. Signal a1A and b1B are fed to the first and second Φ padding phase shifter 128 ₁ and 128 _2. Signals a2A and b3B are sent to the I1 and I2 inputs of a _first 180 ° hybrid 1341 of the kind previously described. Signal b2B and a3A, the second hybrid 134 ₂ of I1 and I2 inputs, sent. Hybrids 134 ₁ and 134 ₂ have differential output D connected as inputs to third and fourth splitters 124 ₃ and 124 ₄ , which perform bi-directional splitting into ratios c1 / c2 and d1 / d2, respectively. produce. Hybrid 134 ₁ and 134 ₂ are also to sum output S is I1 inputs of third and fourth hybrids 134 ₃ and 134 ₄ are respectively connected.

全ての項a1〜f3が比であるので、全ての信号電力は、第一及び第二のスプリッタ124₁及び124₂へそれぞれ入力される信号ベクトルA及びBの比によって表される。 The output signal from the ₂ first and second phase shifters 128 ₁ and 128 is sent to the fifth and sixth splitters 124 ₅ and 124 _6, respectively, the ratio e1 / e2 / e3 and f1 / f2 / f3 Create a three-way split into The output signal from the third splitter 124 ₃ sends (the ratio c1) fifth to I1 inputs of the hybrid 134 _5, and (fraction c2) to a third Φ padding phase shifter 128 _3. The output signals from the fourth splitter 124 ₄ sends (fraction d1) to I1 inputs of the sixth hybrid 134 _6, and (a ratio d2) to a fourth Φ padding phase shifter 128 _4. Output signals from the fifth splitter 124 _5, (the ratio e1) to I2 input of the fifth hybrid 134 _5, (fraction e2) to a fifth Φ padding phase shifter 128 _5, and (ratio e3 ) Send to I2 input of _4th hybrid 1344. Output signals from the sixth splitter 124 ₆ (ratio f1 a) I2 input of the sixth hybrid 134 _6, (fraction f2) to a sixth Φ padding shifter 128 ₆ and (fraction f3) first Send to I2 input of Sanno hybrid 134 ₃ As shown in Table 3 below, antenna elements 122 ₁ -122 ₁₂ are connected to third to sixth hybrids 134 ₃ -134 ₆ , and through respective fixed phase shifters (PS) 136 ₁ -136 ₁₂ , and receiving a driving signal from the output of the third to sixth phase shifters 128 _{3-128 6.}


















Table 3

Since all terms a1~f3 is a ratio, all of the signal power is represented by the ratio of the signal vectors A and B are input to the first and second splitters 124 ₁ and 124 _2.

表4はスプリッタ比を与える、すなわち、総和が1ワットとなるように正規化された電力から、振幅(電圧)を算出する。 Phase shifter 128 ₁ to 128 _6, a hybrid (e.g., 134 ₁₎ to provide compensation for phase shift caused by. Thus, one or more signal components do not pass through the one or more hybrid, two phase shifters (e.g., 128 ₁₎ traversed before reaching antenna elements 122 ₃ and 122 _9, the 360 ° Receive phase shift. Furthermore, the signal or signal component passing through one hybrid traverses one phase shifter (eg 128 ₄ ) and undergoes a relative phase shift of Φ before reaching the antenna element (eg 122 ₂ ).










Table 4

Table 4 gives the splitter ratio, ie, the amplitude (voltage) is calculated from the power normalized so that the sum is 1 watt.

Now referring again to FIG. 8, there is shown a vector diagram for the antenna system 120 when the phase difference between the input signal vectors A and B is 60 °, where 60 ° In the example, the angle at which the phase plane of the antenna array 122 is optimized. The antenna element drive signal is indicated in magnitude and phase by the solid line arrows of the radial vector having antenna element reference numbers 122 _{1 to} 122 ₁₂ and signal power (eg, a1e2A). The component of such a signal (eg, a1e1A) is indicated by a chain line or dotted line vector. Signal b1f2B and a1e2A at each antenna element 122 ₄ and 122 ₉ are part of the input signal vectors A and B, has the same phase as they, therefore, signal b1f2B and a1e1A were marked with each 30 ° 2 The phases are 60 ° apart, as indicated by the two double arrows. This drawing contains complete information regarding the magnitude and phase of the signal and will not be described further.

Referring now to FIG. 9, an antenna system 150 of the present invention is shown for a phased array of _n elements 152 ₁ -152 _n using double variable delay, where n is any positive Is an integer. The first splitter 154 ₁ receives an input signal V _in, it is divided into two signals, such as one of which has twice the power of the other power. Of these two signals, the signal of higher power is fed first to the variable phase shifter 156 _1, lower signal of power is transmitted first secured to the phase shifter 158 _1. This first fixed phase shifter 158 ₁ provides the output signal to the second splitter 154 ₂ via the second fixed phase shifter 158 ₂ , and this second splitter 154 ₂ Divide into n signal parts a1 to an for output by the bus indicated by path P. First variable phase shifter 156 _1, the output signal, provided to a third splitter 154 _3, the third splitter 154 _3, it is divided into n signal parts b1 to bn. The signal parts b2 to bn are output via the third fixed phase shifter 158 ₃ and the bus indicated by the path Q. Signal portion b1 has a power equal to the first signal provided secured to phase shifters 158 _1, are sent to the second variable phase shifter 156 _2, which sends it to a fourth splitter 154 _4, the fourth splitter 154 _4, it is divided into n signal parts c1~cn for output by the bus indicated by path R. The buses indicated by paths P, Q, and R have Na, Nb, and Nc individual conductors, respectively.

The signal portions on paths P, Q, and R are sent to a signal combining and phase shift network, generally indicated at 159. Network 159 is similar to that described with reference to FIGS. 3 and 4 and will not be further described. It has the function of combining and phase shifting the signals to produce an antenna element drive signal that varies depending on the phase adjustment array 152. The use of two variable phase shifters 156 ₁ and 156 ₂ is not essential, but increases the range of angles over which the antenna can be electrically tilted compared to the use of only one variable phase shifter. If a wider range of tilt is required, FIG. 9 can be extended with further combinations of variable phase shifters and splitters. That, b1 variably phase shifted in the 156 _2, in exactly the same manner as to divide the 154 _4, c1 variably phase shifted and create d1~dn divided, variably phase shifted and d1, divided Then you can create e1 ~ en.

Referring now to FIG. 10, there is shown an antenna system 170 of the present invention for a phased array 172 of ₁₀ elements 172 ₁ -172 ₁₀ that uses an interlocked double variable delay. It is a variation of the system 150 described with reference to FIG. The first splitter 174 ₁ receives an input signal Vin, it is divided into two signals one of which has twice the power of the other power. Of these two signals, the signal of higher power is fed first to the variable phase shifter 176 _1, lower signal of power is fed to the first -180 ° phase shifter 178 ₁ It is done. The signal sent to the _first phase shifter 1781 is indicated by vector A. It provides an output signal to a ₂ second splitter 174, the second splitter 174 _2, divide the output signal into four signals A1A～a4A.

First variable phase shifter 176 _1, the output signal, provided to a third splitter 174 _3, the third splitter 174 _3, its output signal into two signals equal to the vector A size Divide. These are one of the two signals is indicated by vector B, are sent to a fourth splitter 174 _4, the fourth splitter 174 _4, it is divided into three signals B1B～b3B. The other of these two signals, via a second variable phase shifter 176 ₂ is sent to a fifth splitter 174 _5, wherein is represented as a vector C, this fifth splitter 174 ₅ , It is divided into three signals c1C-c3C.

Signal b1B and c1C, respectively, via an antenna phase shifter 182 ₃ and 182 ₈ are sent to the antenna elements 172 ₃ and 172 _8. Signal B2B, b3B, C2C, and c3C, respectively, the first type described in the previous, second, third, and fourth 180 ° hybrid 180 _1, 180 _2, 180 _3, and 180 _4, I1 Provide an input signal. These hybrids provide a signal combining network. Signals a1A-a4A each provide an I2 input signal to these hybrids. Respective fixed phase shifters _{(PS) 182 1, 182 2} , 182 4 ~182 7, 182 9, and via 182 _10, the antenna elements 172 _1, 172 _2, 172 _{4 to 172 7,} 172 _9, and 172 _10, a driving signal having an amplitude as shown in Table 4 below, receives the output of the hybrid 180 _{1-180 4,} and equivalents of elements 172 ₃ and 172 ₈ are added. Here, N / A means inappropriate.
Table 5

可変移相器176₁及び176₂は、ともに変化して、等しい移相を与えるように、矢印及び点線で示すように連動する。それらは、チルト制御機構186によって制御される。 The splitter ratio values are given in Table 6 below, where the voltage was calculated from the power normalized so that the total was 1 watt as described above.



Table 6

Variable phase shifters 176 ₁ and 176 _{2 work} together as shown by the arrows and dotted lines to change together to give equal phase shifts. They are controlled by a tilt control mechanism 186.

The top half of the array 172 only (the antenna elements 172 _{6-172 10),} a signal contribution associated with the ratio c1 etc., may receive from the fifth splitter 174 _5, 10 Karawakari, these contributions are 176 in ₁ and 176 ₂ has received the two variable phase. Furthermore, only the lower half of the array 172, i.e. the antenna elements 172 _{1 to 172 5,} the signal contribution associated with the ratio b1 etc., received from the fourth splitter 174 _5, these contributions, in 176 _1, one of Has undergone variable phase shift. Both halves of the array 172 (other than antenna elements 172 ₃ and 172 _8), from the second splitter 174 _2, receives signal contributions a1A etc., these contributions, in 176 ₁ or 176 ₂ receives the variable phase Not.

  Referring now to FIG. 11, the antenna system of the present invention can be implemented as a single feeder system or a dual feeder system. In a single feeder system, a single signal input 200 provides a signal Vin via a feeder 202 to an antenna assembly 204 that can be mounted on a mast with an antenna array 206. Signal splitting, variable and fixed phase shifts, and vector combinations as previously described are implemented in an assembly 204 on the mast. This has the advantage that only one signal supply needs to be sent from the remote user to the antenna system, but the remote operator has no access to the antenna assembly 204 on the mast. The angle of electrical tilt cannot be adjusted. Also, all operators sharing a single antenna will have the same angle of electrical tilt.

  FIG. 12 shows the antenna system of the present invention implemented as a dual feeder system 210. The system has a tilt control 212 that generates two signals V2A and V2B, as previously described, and these signals are sent to the antenna array 216 via respective feeders 214A and 214B. Here, the control unit 212 can also be placed with the user away from the antenna array 60 and the mast to which it is attached, and the antenna supply network 218 (see, e.g., FIG. 4) can be placed in the same location as the antenna array 216. It can also be arranged. Signal splitting as previously described, (and if further variable phase shifts are desired) and fixed phase shifts and vector combinations are implemented in assembly 216. Here, the user can directly access the tilt control unit 212 to adjust the angle of the electrical tilt away from the antenna array 60 and the mast, independently of other users sharing the antenna assembly 216. This adjustment can be made.

  In dual feeder equipment, the sensitivity of the tilt is reduced to reduce the effect of the phase difference between the feeders, for example, the difference between the electrical tilt angle required by the operator and the electrical tilt angle at the antenna. It is also convenient. With each tilt control unit 212 arranged with each operator, a shared antenna system having individual tilt angles can be implemented for each operator on the input side of the frequency selective coupler arranged at the operator's base station. Is possible.

  FIG. 13 shows a phased array antenna system 240 of the present invention that is equivalent to the system shown in FIG. 3 with modifications for use in both receive and transmit modes. Parts previously described are given the same reference numbers preceded by 200 and only the changes are described. Here, the variable phase shifter 246 for controlling the tilt is used only in the transmission (Tx) mode, and is connected in series between the bandpass filters (BPF) 245 and 247 in the transmission path 243. There is also a similar receive (Rx) path 249 with a variable phase shifter 251 in series between the bandpass filters 253 and 255 and a low noise amplifier or LNA 257. The transmit and receive frequencies are usually sufficiently different that they can be separated from each other by a bandpass filter 245 or the like.

  There are further, mostly equivalent transmit and receive paths 243f and 249f associated with a fixed phase shift ψ. These have elements that are given the same reference number followed by f. The second transmission path 243f has a fixed phase shifter 246f between the bandpass filters 245f and 247f. The second reception path 249f includes a fixed phase shifter 251f and an LNA 257f between the bandpass filters 253f and 255f.

In addition to operating in transmit mode, elements 242, 244, 252, 254, 256, and 258-265 have the ability to operate in reverse in receive mode, eg, with a splitter as a combiner. The only difference between the two modes is that in transmit mode, feeder 265 provides input and the transmit signal traverses transmit paths 243 and 243f from left to right, whereas in receive mode the received signal is Traverse receive paths 249 and 249f from right to left, and feeder 265 provides their combined output. In response to receiving a signal from free space, by the antenna element signals to the phase shift and coupling generated by the array 262, the circuit 264 ₁ ~264 _n, and 260-254, the received signal is generated. System 240 is advantageous because it allows the angle of electrical tilt in both transmit and receive modes to be adjusted independently and equalized. Usually (unfortunately) this is not possible because the components of the antenna system have different frequency dependent characteristics at different transmit and receive frequencies.

  Referring now to FIG. 14, there is shown a phased array antenna system 300 of the present invention for use in transmit and receive modes by multiple (two) operators 301 and 302 of a single phased array antenna 305. Yes. Parts equivalent to those described previously are given the same reference numbers preceded by 300. The figure has a number of different channels, the equivalent parts in the different channels are given the same numerical reference numbers with one or more subscripts, the subscript T or R indicates the transmit or receive channel, the subscript 1 or 2 indicates the first or second operator 301 or 302, and the subscript A or B represents the path of A or B. Omission of these subscripts from the number of the first part of the reference number (for example, 342) means that all elements having the number of the first part are referred to.

  First, the transmission channel 307T1 of the first operator 301 will be described. This transmit channel provides an RF input 342 to splitter 344T1, which splits the input between variable phase shifter 346T1B and fixed phase shifter 348T1B. Signals are sent from phase shifters 346T1A and 348T1B to bandpass filters (BPF) 309T1A and 309T1B in different duplexers 311A and 311B, respectively. The band filters 309T1A and 309T1B have the center of the pass band at the transmission frequency of the first operator 301, and this frequency is expressed as Ftx1 as shown in the drawing. The first operator 301 is also represented by Frx1 as the reception frequency, and their equivalents in the second operator 302 are Ftx2 and Frx2.

  The transmission signal of the first operator output from the leftmost band filter 309T1A at the frequency Ftx1 is similarly extracted, and the transmission signal of the second operator output from the adjacent band filter 309T2A at the frequency Ftx2, The first duplexer 311A is coupled. These combined signals are sent along the feeder 313A to an antenna tilt network 315 of the type described in the previous example and from there to the phased array antenna 305. Similarly, the other transmission signal of the first operator output from the band filter 309T1B at the frequency Ftx1 is similarly extracted, and the transmission of the second operator output from the adjacent band filter 309T2B at the frequency Ftx2. The signal is combined with the second duplexer 311B. These combined signals are sent along the second feeder 313B to the phased array antenna 305 via the antenna tilt network 315. Despite using the same phase-adjusted array antenna 305, the two operators simply adjust in each case a single variable phase shifter, i.e., variable phase shifter 346T1A or 346T2A, respectively. The angle of transmission electrical tilt can be changed independently and away from the antenna 305.

  Similarly, the reception signal returning from the antenna 305 via the network 315 and the feeders 313A and 313B is divided by the transmission / reception switchers 311A and 311B. These split signals are then filtered and separated into individual frequencies Frx1 and Frx2 in bandpass filters 309R1A, 309R2A, 309R1B, and 309R2B, which are variable phase shifters 346R1A, 346R2A, and fixed phase shifters Signals are provided to 348R1A and 348R1B, respectively. Next, by adjusting the variable phase shifters 346R1A and 346R2A, respectively, the angle of the electric tilt of reception can be adjusted independently by the operators 301 and 302. Signals for two or more operators will also be combined in transmission and split in reception by duplicating components. That is, instead of components having subscripts 1 and 2, there will be the same components with subscripts 1 to m, where m is the number of operators.

FIG. 15 shows a phased array antenna system 470 of the present invention that is generally the same as shown in FIG. The parts described above are given the same reference numbers with 400 instead of 100 instead of 100, and only the changed parts will be described. System 470 has a first splitter 474 ₁ separating the input RF carrier signal at 473 into two parts, one of the two parts, through the first variable phase shifter 476 _1, the first To the second feeder 477 ₁ and the other directly to the second feeder 477 ₂ . Elements 473-477 ₂ are located at or near cellular mobile radio base stations (not shown). The feeders 477 ₁ and 477 ₂ connect the base station to a radar dome 479 of a remote antenna, and a second variable phase shifter 476 ₂ is placed in the radar dome 479.

The system 470 has been previously described with reference to FIG. 10, except that the first and second variable phase shifters 476 ₁ and 476 ₂ are no longer interlocked but instead are adjusted independently. Operates as follows. It offers the advantage that each operator sharing the antenna 472 can be given an individual electrical tilt angle (using frequency selective coupling as shown in FIG. 14), but the tilt common to all operators The range is extended. In fact, the angle of electrical tilt set by the second variable phase shifter 476 _2, conveniently, it can be an average of the individual electrical tilt angles of all the operators sharing the antenna 472.

Figure 15 shows a second variable phase shifter 476 ₂ adjustments within the antenna radome 479, it also uses a servo mechanism control device, it can be set away from the radome 479 (Not shown). Additional variable phase shifters can be added to the antenna system 470 according to the present invention to further extend the range of tilt common to all operators.

FIG. 16 shows a phased array antenna of the present invention using an input splitter SP ₁ , parallel line couplers (PLC) SP ₂ and SP ₃ , and 180 ° ring hybrids SP _{4 to} SP ₁₁ and H _{1 to} H _6. A further embodiment of the system 500 is shown. Here, SP such as SP ₁ indicates a splitter, and H such as H ₁ indicates a hybrid used as a sum and difference (SD) generator. Each of the hybrid SP _{4 to} SP ₁₁ and H _{1 to} H ₆ has four ports, ie first and second input ports, indicated by inward and outward arrows, respectively, and first and This is the second output port. The output ports of each of the SD generator hybrids H _{1 to} H ₆ are sum and difference outputs, indicated by S and D, respectively. The individual ring hybrid SP _{4 to} SP ₁₁ and H _{1 to} H ₆ ports are in each case a distance λ / 4 from one port and a distance from the other port around the circumference of the ring. 3λ / 4 apart. Here, lambda is the wavelength of the signal V _in of the ring component.

The signal applied to the input ports of any ring hybrid SP _{4 to} SP ₁₁ and H _{1 to} H ₆ is divided into two components that are sent clockwise and counterclockwise around the ring, respectively. It has a circumference of (n + 1/2) λ, where n is an integer. These components are defined in relative amplitude by the relative impedance of the path in the ring along which they are routed, which allows the splitter ratio to be predetermined. Two signals received from each input port that are separated by λ / 4 from the output port are in phase and are added together to give a sum output. The two signals received from the respective input ports separated by λ / 4 and 3λ / 4 from the output port are in anti-phase and are subtracted from each other to give a differential output. At the output port separated by λ / 2 from the input port, the two signals received via the clockwise and counterclockwise paths respectively from the input port are in anti-phase and if the path impedances are equal, Will give a vector sum of zero. This therefore separates the ports from each other by λ / 2.

Each ring hybrid SP _{4 to} SP ₁₁ used as a splitter has a first input terminal (inward arrow) connected to receive the input signal and a second input terminal connected to the respective termination T (matching Connected to the load). Termination T provides a zero input signal, therefore, a ring hybrid or splitter SP ₄ to SP ₁₁ is a signal of their first input terminal, identified by the impedance ratio between the input terminal and the output terminal in each case Divide between their respective output terminals at each division ratio.

In the system 500, as in the previous embodiment, the first splitter SP _1, divide the input signal V _in, into two equal signals reduced to each -3dB compared to the power of the input signal V _in. One signal so formed passes through the variable phase shifter 502 and appears as a vector A on the first feeder 504. Such other signals were formed appears as a vector B on the second feeder 506, i.e., as described in the previous, between the first splitter SP ₁ and the second feeder 506, It is possible to include a fixed phase shift (not shown).

Signal vectors A and B, as inputs, respectively, and sent to PLC SP ₂ and SP _3, each of the PLC will have two output terminals O1 and O2, and a fourth terminal T ₄ is a matched load T Terminated with a zero input signal. From that input, each of the PLCs SP ₂ and SP ₃ generates a signal at the output terminals O1 and O2 that in each case has its power reduced to -0.12 dB and -16.11 dB, respectively, compared to the input signal. The _two resulting -0.12 dB signals from PLC SP ₂ and SP ₃ are sent to the first input terminals of the fifth and eighth splitters SP ₅ and SP ₈ respectively, whereas -16.11 dB of signals are fed to the first input terminal of the sixth and seventh splitters SP ₆ and SP _7.

The fifth splitter SP ₅ divides its input signal into output signals whose power is reduced to -5.3 dB and -1.5 dB from the power of the input signal, and these output signals are respectively connected to the fourth splitter SP. _4, and it is fed to the first of the first input terminal SD generator H _1. Similarly, the eighth splitter SP ₈ splits its -0.12 dB input signal into output signals that are -5.3 dB and -1.5 dB lower than the input signal, and these output signals are respectively the ninth splitter SP. ₉ and the first input terminal of the _second SD generator H2.

The fourth splitter SP ₄ divides the −5.42 dB input signal into output signals that are −1.88 dB and −4.94 dB lower than the input signal. Of these, the 1.68 dB output signal is sent via line L4 to fixed phase shifter PE4 and from there to antenna element E4 of 12-element antenna array E. There is one such line Ln for each combination of fixed phase shifter / antenna elements PEn / En (n = 1-12). The connection of the line Ln to the fixed phase shifter PE _n is not clearly shown to avoid too many overlapping lines, but in any case is indicated with “PEn” at the end of the line Ln. The output signal of −4.94 dB from the fourth splitter SP ₄ is sent to the second input terminal of the second SD generator H ₂ .

The ninth splitter SP ₉ divides the input signal into output signals that are −1.68 dB and −4.94 dB lower than the input signal. Of these, the 1.68 dB output signal is sent to antenna element E9 via line L9 via fixed phase shifter PE9. The 4.94 dB output signal is sent to the second input terminal of the _first SD generator H1.

The sixth splitter SP ₆ is a uniform splitter that produces two output signals, each 3 dB lower than its input signal. One of these output signals is fed to the first input terminal of the fifth SD generator H _5, and the other is sent to a third of the first input terminal SD generator H _3. The seventh splitter SP ₇ is also an equal splitter that produces two output signals, each 3 dB lower than its input signal, the output signal of which are the fourth and sixth SD generators H ₄ and H _{6 respectively} . Sent to one input terminal. The first SD generator H ₁ is the sum output S is connected to a second input terminal of the fourth SD generator H _4. Difference output D is connected to the input terminal of the tenth splitter SP ₁₀ of. Similarly, the second SD generator H ₂ is the sum output S is connected to a second input terminal of the fifth SD generator H _5. That is, the differential output D is connected to the input terminal of the _eleventh splitter SP11.

Tenth splitter SP ₁₀ of a uniform splitter to produce each 3dB lower two equal output signals from its input signal from the first SD generator H _1. One of these output signals is sent to antenna element E2 via line L2 via fixed phase shifter PE2. The other of these output signals is sent to the second input terminal of the _third SD generator H3. Similarly, the eleventh splitter SP ₁₁ is also an equal splitter producing each 3dB lower two equal output signals from its input signal from the second SD generator H _2. One of these output signals, the lines L11, via a phase shifter PE11, sent to the antenna element E11, and the other feed to the second input terminal of the sixth SD generator H ₆ It is done.

Third to sixth SD generator H ₃ to H _6, respectively lines L1, L3, L5 to L8, L10, and L12, and the phase shifter PE1, PE3, PE5~PE8, via the PE 10, and PE12 And have sum and difference outputs S and D that provide drive signals to antenna elements E1, E3, E5-E8, E10, and E12. Make a direct comparison of the power of the input signal Vin with the power of the signal received by the antenna element by adding the dB value indicated in each signal path (ignoring losses in non-ideal components) Can do. For example, -9.1DB antenna element E4 is, splitter _{SP 1, SP 3, SP 5} , and the SP _4, compared with the input power, -3 dB, respectively, -0.12 dB, -5.3DB, and -1.68DB, in total Receive a reduced signal. The relative phase adjustment of the antenna element drive signal is not described as an analysis equivalent to the analysis given for the previous embodiment with modifications as necessary.

  The embodiment of the invention described above uses a 180 ° hybrid. They can be replaced with, for example, a 90 ° “quadrature” hybrid with the addition of a 90 ° phase shifter to achieve the same overall function, but this is not practical.

  The example of the present invention based on the continuous connection of splitter and hybrid abbreviated as (S-H) has been described. From these, further examples of the invention with further steps, such as, for example, S—H—S, S—H—S—H, etc., can be devised.

Fig. 4 shows a vertical radiation pattern (VRP) of a phased array antenna with zero and non-zero electrical tilt angles. 1 illustrates a prior art phased array antenna with adjustable electrical tilt angle. It is a block diagram of the phase adjustment array antenna system of this invention. Fig. 4 shows in more detail the signal combining network used in the system of Fig. 3; FIG. 4 is a phase characteristic diagram of an antenna element signal associated with a 90 ° phase shift provided by a variable phase shifter in the system of FIG. FIG. 6 is a block diagram of a portion of a further phased array antenna system of the present invention that includes 11 antenna elements (element spacing is not reduced exactly). FIG. 6 is a block diagram of a portion of a further phased array antenna system of the present invention that includes 12 antenna elements. FIG. 8 is a phase characteristic diagram of an antenna element signal associated with a 90 ° phase shift provided by a variable phase shifter in the system of FIG. FIG. 5 is a block diagram of a portion of a further phased array antenna system of the present invention that uses two variable phase shifters. FIG. 10 is a block diagram of a part of the antenna system of the present invention similar to that shown in FIG. 9, but using an interlocking variable phase shifter. Fig. 4 illustrates the use of the present invention with a single feeder. Fig. 4 illustrates the use of the present invention in a dual feeder. Fig. 4 shows a modification to the present invention that allows the angle of electrical tilt in transmit and receive modes to be adjusted independently. FIG. 6 is a block diagram of a further phased array antenna system of the present invention with dual feeders and individual tilt and transmit / receive capabilities showing antenna sharing by multiple users. FIG. 6 is a block diagram of a further phased array antenna system of the present invention with dual feeders and individual tilt and transmit / receive capabilities showing antenna sharing by multiple users. FIG. 10 is a variation of the antenna system of FIG. 9 in which the variable phase shifters are spaced apart from one another. 1 illustrates a phased array antenna system of the present invention including a ring hybrid coupler.

Claims (30)

A phased array antenna system having an adjustable electrical tilt and comprising an array of antenna elements,
a) a variable phase shifter for providing a variable relative phase shift between the first RF signal and the second RF signal;
b ) a dividing device for dividing the relative phase-shifted first and second signals into respective component signals; and
c ) a signal combining network for forming a vector combination of the component signals, which consists only of passive processing devices , the combination of the dividing device and the signal combining network comprising drive signals for individual antenna elements Wherein the drive signal comprises at least in part the vector combination, and in response to a change in the variable relative phase shift caused by the variable phase shifter, the electrical tilt of the array A signal combining network whose phase gradually changes throughout the array as a function of the position of the antenna elements, such that the angle of is adjustable, and as required for operation of the phased array,
A system characterized by including. With an odd number of antenna elements,
The system according to claim 1, wherein: The variable phase shifter is a first variable phase shifter, and the system is a second variable arranged to phase shift a component signal phase shifted by the first variable phase shifter. A phase shifter, wherein the second variable phase shifter is connected to the signal combination network either directly or via one or more splitter / variable phase shifter combinations. Provide output,
The system according to claim 1, wherein: The variable phase shifter is one of a plurality of variable phase shifters, and the signal coupling network, some of which pass through all the variable phase shifters, and some of which Arranged to produce antenna element drive signals from component signals that do not pass through variable phase shifters,
The system according to claim 1, wherein: The splitting device is arranged to split the component signal into further component signals for input to the signal combining network;
The system according to claim 1, wherein: The signal combining network uses a phase shifter and a hybrid combiner (hybrid) to phase shift and form a vector combination.
The system according to claim 1, wherein: The hybrid is a 180 ° hybrid,
The system according to claim 6. The hybrid is a ring hybrid in which the circumference is (n + 1/2) λ and adjacent ports are separated by λ / 4, where λ is used to configure each ring hybrid using its components The wavelength of the RF signal,
The system according to claim 6. The splitting device includes a ring hybrid having a circumference of (n + 1/2) λ, two input ports and two output ports, adjacent ports separated by λ / 4, one of each of these hybrids. One input port is terminated with a resistor equal to the system impedance to form a matched load,
9. The system according to claim 8, wherein: The hybrid was designed to convert input signals I1 and I2 into vector sums and differences other than (I1 + I2) and (I1-I2),
The system according to claim 6. The splitting device , the variable phase shifter, and the signal coupling network are arranged as an antenna assembly at the same location as the antenna element array, and the system converts the RF signal into a first RF signal and a second RF signal. An additional splitting device for splitting, the assembly having a single RF input power feeder for supplying an RF signal from a remote signal source to the additional splitting device,
The system according to claim 1, wherein: The second splitter includes first and second splitters , and the system includes an additional splitter for splitting an RF signal into a first RF signal and a second RF signal, and the additional splitter A split device is disposed with the variable phase shifter away from the split device, and the split device, the signal coupling network, and the antenna element array are disposed at the same place as an antenna assembly, and the assembly Product has a dual RF input power feeder for supplying the antenna assembly with first and second RF signals from a remote signal source where the additional divider and variable phase shifter are located ,
The system according to claim 1, wherein: The variable phase shifter is a first variable phase shifter connected in a transmission channel, and the system provides a second variable phase shifter connected in a reception channel, and a fixed phase shift The signal combining network includes an additional transmit and receive channel, and the signal combining network generates an antenna element drive signal in response to the signal in the transmit channel, and from the signal generated by the antenna element operating in receive mode, the receive channel signal Is arranged to operate in both transmit and receive modes, and the system has an electrically adjustable electrical tilt in both transmit and receive modes,
The system according to claim 1, wherein: The variable phase shifter is one of a plurality of variable phase shifters associated with each operator, and the system provides a common signal after the phase shift in each variable phase shifter Including a filtering and combining device for sending to the device, the common signal supply device providing the antenna array with a signal including contributions from the splitting device and both operators, with the electrical tilt adjustable independently The system according to claim 1, wherein the system is connected to the signal coupling network. The plurality of variable phase shifters includes a respective pair of variable phase shifters associated with each operator, and the system is configured with an electrical tilt that is independently adjustable in both transmit and receive modes. Having components with both forward and reverse signal processing capabilities to operate in transmit and receive modes;
15. The system according to claim 14, wherein: A method for adjusting the electrical tilt of a phased array antenna system including an array of antenna elements, comprising:
a) providing a variable relative phase shift between the first RF signal and the second RF signal;
b ) dividing the relative phase-shifted first and second signals into respective component signals; and
c ) By only a passive processing unit , form vector combinations of the component signals to provide respective drive signals for individual antenna elements, the drive signals consisting at least in part of the vector combinations In response to changes in the variable relative phase shift introduced by the variable phase shifter, the angle of the electrical tilt of the array can be adjusted and as required for operation of the phased array , Its phase gradually changes across the array as a function of antenna element position,
A method comprising steps. The array has an odd number of antenna elements;
The method according to claim 16, wherein: Generating at least one component signal having a phase shift collectively applied by a plurality of variable phase shifters;
The method according to claim 16, wherein: The variable phase shifters are interlocked, and the method has some of the phase shifts applied collectively by all the variable phase shifters, some of which are all the variable phase shifters. Generating an antenna element drive signal from component signals having no phase shift applied collectively by
The method according to claim 18, wherein: Dividing the component signal into additional component signals to form additional vector combinations and provide additional antenna element drive signals;
The method according to claim 16, wherein: Using a phase shifter and a hybrid to phase-shift the component signals and form a vector combination;
The method according to claim 16, wherein: The hybrid is a 180 ° hybrid,
22. A method according to claim 21, wherein: The hybrid is a ring hybrid with a circumference of (n + 1/2) λ and adjacent input and output ports separated by λ / 4, where n is an integer and λ is its component Is the wavelength of the RF signal that each ring hybrid is made up of,
22. A method according to claim 21, wherein: The splitting device includes a ring hybrid with a circumference of (n + 1/2) λ, two input ports and two output ports, adjacent ports separated by λ / 4, one of each of these hybrids The input port is terminated with a resistor equal to the system impedance to form a matched load.
24. A method according to claim 23. The hybrid was designed to convert input signals I1 and I2 into vector sums and differences other than (I1 + I2) and (I1-I2),
24. A method according to claim 23. In a network that is co-located with the antenna array and forms an antenna assembly with the antenna array, the RF input signal for splitting, variable phase shifting, and forming vector coupling as a single RF input signal, Including feeding from a remote signal source,
The method according to claim 16, wherein: The first and second RF signals having variable phase with respect to each other are supplied from a remote signal source to the antenna assembly to form splits and vector combinations in a network co-located with the antenna array. Including that,
The method according to claim 16, wherein: Depends on the signal in the transmit channel, using transmit and receive channels for operation in both transmit and receive modes, and with electrical tilt adjustable independently in both transmit and receive modes Generating an antenna element drive signal and generating a receive channel signal from a signal generated by an antenna element operating in receive mode,
The method according to claim 16, wherein: The variable phase shift is one of a plurality of variable phase shifters, the first and second RF signals are a single pair, and the pair is a plurality of relative phase shifted RF signals. One of the pair,
Each variable phase shift and each pair is associated with a respective operator,
a) Filter and combine the signals after phase shifting in each variable phase shifter for execution of the subsequent split and vector combination forming steps;
b) providing a signal including the contribution from each operator to the antenna; and
The method of claim 16, comprising the step of: c) independently adjusting the electrical tilt associated with each operator. The plurality of variable phase shifts are realized by respective pairs of variable phase shifters associated with each operator, and the method uses components with both forward and reverse signal processing capabilities, 30. The method of claim 29, comprising operating in a transmit and receive mode with independently adjustable states in both modes.

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