RU2587495C2 - Method of transmitting signals through omnidirectional circular log periodic vertically polarised antenna array and antenna array therefor - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and is intended, in particular, for use in mobile communication systems in metre and decimetre wavelength range. Disclosed is a method of transmitting signals through an omnidirectional log periodic vertically polarised circular antenna array with division of full operating frequency band of antenna into first and second transmission frequency ranges. Sections of first transmission range are located between sections of second transmission range. When dividing full operating frequency band into first and second transmission frequency ranges, said transmission frequency ranges are assigned with partial overlap of transmission bands of first and second frequency transmission ranges and signals falling in frequency overlap zone of said two transmission frequency ranges and having matching allocated transmission frequencies, are transmitted via both transmission ranges through all sections of antenna array. Also disclosed is an antenna that realises said method.

EFFECT: technical result is expansion of frequency band of omnidirectional circular antenna array due to reduced effect of increasing electric radius of array.

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Description

Technical field

The invention relates to radio engineering and is intended, in particular, for use as a transmitting antenna for transmitting messages in mobile communication systems: land mobile, air mobile and marine mobile radio communications in the meter and decimeter wavelengths.

State of the art

For the organization of radio communication with mobile subscribers in professional radio communication systems, vertical polarization antennas are usually used, omnidirectional in the horizontal plane, for example, asymmetric vertical vibrators (Aizenberg G.Z., Yampolsky V.G., Tereshin O.N. Antennas VHF / Ed. G.Z. Eisenberg. In the 2 part of Part 2 - M .: Communication, 1977. - 288 p.). These antennas provide good uniformity of directivity in the horizontal plane, but can only be placed on the top of the support, which limits the working frequency range for such antennas.

Omnidirectional antenna arrays are known in which annular arrays of vertical polarized emitters are used that are evenly spaced around the support (RF patent for the invention No. 2206159, H01Q 21/20 from 06/10/2003). The width of the working frequency band of the log-periodic antenna with a sufficiently large number of vibrators in its composition can be an octave or more. However, the broadband of the ring gratings is limited not only by the broadband of the emitters included in them, but also by a relatively narrow frequency band, in which the radiation pattern of the ring grating with fixed distances between the emitters remains quasi-circular with acceptable unevenness. With an increase in the operating frequency, the electric distance between the grating emitters increases correspondingly. Starting from a certain frequency, the level of dips (minima) of the azimuthal radiation pattern becomes unacceptably low. When using log-periodic antennas as emitters of a circular antenna array, the indicated effect of the frequency dependence of the electric distance between the emitters is further enhanced, since with increasing frequency the position of the equivalent phase center of the emitter shifts in the direction of the main radiation of the log-periodic antenna, i.e. in fact, the radius of the lattice increases. All this significantly limits the broadband omnidirectional ring antenna arrays.

Known log-periodic combined antenna containing a flat antenna containing several modules, each of which has its own operating frequency range, while the operating ranges often for individual modules do not overlap each other (RF patent for the invention No. 2427946, H01Q 11/10 from 08/27/2011 ) As the authors of this invention note, potentially this antenna can use a wide range of frequencies, meter, decimeter and centimeter radio waves, but in this antenna array there are all restrictions on the working range of each of the modules due to signal attenuation at the boundaries of the working given module. In addition, using an antenna of this type, it is impossible to obtain uniform omnidirectional radiation of the signal, which is necessary when working with moving objects.

The present invention solves the problem of expanding the operating frequency band when transmitting messages to mobile receiving stations.

SUMMARY OF THE INVENTION

To solve this problem, a method for transmitting signals through an omnidirectional log periodic periodic antenna array of vertical polarization, based on dividing the full working frequency band of the antenna into the first and second transmission frequency ranges, allocating an omnidirectional ring antenna array for each of the transmission ranges of their sections, assigning channel signals to the transmitted signals transmission with a dedicated transmission frequency, the distribution of the assigned transmission channels by transmission ranges in accordance AI with a dedicated transmission frequency and transmitting antenna signals at dedicated transmission frequencies through the corresponding sections of the antenna array, while the sections of the first transmission range are located between the sections of the second transmission range, and when dividing the full working frequency band into the first and second transmission frequency ranges, these transmission frequency ranges with partially overlapping transmission bands of the first and second transmission frequency ranges, and signals falling into the frequency overlapping zone of these two transmission frequency ranges and and having matching allocated transmission frequencies, transmit over both transmission ranges through all sections of the antenna array.

Moreover, in the proposed method in the first and second transmission ranges, an eight-section omnidirectional antenna with four sections for each range is used, while providing, including, but not limited to, the following modes of input excitation: 1) signals at the inputs of adjacent 1st, 2nd , The 3rd and 4th elements in each section are shifted relative to each other by + 90 °; 2) the signals at the inputs of adjacent 1st, 2nd, 3rd and 4th elements in each section are offset by -90 ° relative to each other; 3) the signals at the inputs of two opposite elements provide in-phase, orthogonal elements do not excite them.

To solve this problem, it is also proposed a broadband omnidirectional ring log-periodic antenna array of vertical polarization containing emitters evenly located on the central support, sections of a log-periodic antenna of vertical polarization arranged in two groups of sections are used as emitters, one group of sections of the antenna array is configured to operate in high-frequency transmission range, and another group of sections of the antenna array is configured to operate in low the frequency range of transmission, partially covering the high-frequency transmission range of the aforementioned group of sections, while the sections of the emitters of both groups are located in the same plane so that the sections of the emitters of one group are located between the sections of the emitters of the other group, while the emitters of both groups operating in the overlapping frequency range are connected to frequency separation devices providing separation of the low-frequency and high-frequency ranges with a partial overlap of these transmission ranges, etc. wherein each frequency-distribution device has one input and two outputs, so that the outputs of each frequency-separating devices are connected corresponding inputs of two adjacent radiators, and inputs the frequency-dividing devices are interfaces array antenna for transmitting / receiving a signal.

The omnidirectional ring antenna array is characterized in that it is equipped with eight sections of emitters and four interfaces, while the inputs of the sections of the array are connected to the interfaces of the antenna array through a beam-forming device that provides the normalized vector of complex voltage amplitudes at the inputs of the array [1, -i, -1, i], [1, i, -1, -i], [1, 0, 1, 0], [0, 1, 0, 1] for the 1st, 2nd, 3rd and 4th mod, respectively, where i is the imaginary unit.

The technical result of the invention is to expand the frequency band of an omnidirectional ring antenna array by reducing the effect of increasing the electric radius of the array.

To achieve the indicated technical result, the proposed transmission method and the antenna array are based on dividing the full working frequency band of the known omnidirectional ring antenna array with rotational symmetry, made on the basis of the emitters evenly located on the cylindrical support, into the first (low-frequency) and second (high-frequency) ranges with organization for each of the ranges of its sections of the lattice. The elements of the sections of each range perform narrower than the elements of the sections of the antenna array without frequency separation, respectively, provides a smaller deviation of the positions of the equivalent phase centers of the emitters in the working frequency band. The first and second frequency ranges are set adjacent to the partial overlapping of the bands, while the signals falling into the area of mutually overlapping regions of the ranges are transmitted simultaneously on both ranges through all sections of the antenna array. Separation of the total frequency band of the antenna array into the first and second ranges is carried out using frequency separation devices (CIA), each of which is performed, for example, in the form of a “filter plug”, which is a combination of a high-pass filter (HPF) and a low-pass filter ( Low-pass filter). The first range, in particular, can be allocated by the low-pass filter, and the second - the high-pass filter, built with partially overlapping passband. Moreover, the selected low-pass filters of the first range are fed to the inputs of the elements of the first section of the antenna array; dedicated high-frequency signals of the second range - to the inputs of the elements of the second section of the antenna array; frequency signals in the mutually intersecting region of the passband of the low-pass and high-pass filters are applied to the inputs of the elements of both sections of the antenna array, respectively.

As an embodiment of the invention, it is proposed to use an eight-section omnidirectional antenna with four sections for each band in the first and second transmission ranges, while the extension of the working frequency band is provided (including, but not limited to) the following input drive modes:

1) the signals at the inputs of adjacent 1st, 2nd, 3rd and 4th elements in each section are offset by + 90 ° relative to each other;

2) the signals at the inputs of adjacent 1st, 2nd, 3rd and 4th elements in each section are offset by -90 ° relative to each other;

3) the signals at the inputs of two opposite elements provide in-phase, orthogonal elements do not excite them,

which ensures the formation of four independent radiation patterns.

A device that implements the inventive method involves the use of log periodic antennas of vertical polarization of the first and second frequency ranges, respectively, as sectional elements in an omnidirectional ring antenna array with rotational symmetry, made on the basis of radiators uniformly located on a cylindrical support. The elements of the first and second sections are placed alternately on the support and are connected to the switchgear, providing, with partial overlap, separation of the first and second ranges and having each one input and two outputs, so that the corresponding inputs of two adjacent radiators are connected to the outputs of the switchgear, and the inputs of the switchgear form grating inputs.

In another embodiment, the inputs of the aforementioned broadband omnidirectional ring antenna array containing 8 emitters are connected to four transmitters or receivers through a diagram-forming device that provides the normalized vector of complex voltage amplitudes at the inputs of the array [1, -i, -1, i], [-i , 1, i, -1], [-i, 0, -i, 0], [0, -i, 0, -i] for the 1st, 2nd, 3rd and 4th transmitter ( receiver), respectively, where i is the imaginary unit, which ensures the formation of four independent radiation patterns.

Brief Description of Drawings

The invention is illustrated by drawings.

In FIG. 1 shows a schematically proposed broadband omnidirectional antenna array, top view; in this case, the grating contains 8 emitters.

In FIG. 2, the proposed antenna array is shown schematically in a perspective view.

In FIG. 3 shows a diagram of the connection of emitters to frequency-separation devices.

In FIG. 4 shows a connection diagram of an antenna array to a beam-forming device.

In FIG. 5 shows a diagram of a variant of a beam-forming device.

Figure 6 ... 8 shows the radiation patterns in the horizontal plane for a particular variant of the 8-element array.

Description of Embodiments

Broadband omnidirectional antenna array (Fig. 1 and 2) is an annular antenna array with rotational symmetry (Fig. 1), the emitters of which 1, 2 are uniformly located on the cylindrical support 3. Log emitters of vertical polarization of two partially overlapping frequency ranges are used as emitters - low-frequency 1 and high-frequency 2, placed on the support in turn, so that the sections of the emitters of the first range of transmission frequencies are located between the sections of the emitters of the second range on gear frequencies. The emitters are connected (Fig. 3) to the frequency separation devices 4, providing, with partial overlap, the separation of the low-frequency and high-frequency ranges. The bandwidth of the overlapping frequencies of the high-frequency and low-frequency ranges lies within (5 ... 15)% of the working frequency bandwidth of the grating and is refined by optimizing the spatial characteristics of a specific grating. The frequency separation device has one input 5 and two outputs: low-frequency range 6 and high-frequency range 7. As a frequency-separation device, for example, a well-known device such as “filter plugs” is used (A. Buzov VHF antennas for radio communication with moving objects broadcasting and television. - M.: Radio and communications, 1997), and the low-pass filter is connected between the input of the frequency separation device 5 and the output of the low-frequency range 6, and the high-pass filter is between the input of the frequency separation device 5 and the output of high hours 7. otnogo range to the outputs 6 and 7 of each frequency-separating devices are connected corresponding inputs of two adjacent radiators 1, 2, and inputs the frequency-dividing device 5 inputs a lattice form.

In another embodiment (Fig. 4), the inputs of 5 frequency-separating devices, which are the inputs of a grating containing eight emitters, are connected to four transmitters or receivers through a diagram-forming device 8, which provides the values of the normalized vector of complex voltage amplitudes at its outputs 13, 14, 15, 16 (ie, at the inputs of the grating) [1, -i, -1, i], [-i, 1, i, -1], [-i, 0, -i, 0], [0, - i, 0, -i] (where i is the imaginary unit) when applying signals to the inputs 9, 10, 11, 12 of the beam-forming device, respectively. The result is the formation of four independent radiation patterns.

The diagram-forming device (Fig. 5) is constructed according to the well-known “truncated” Butler matrix (Buzov A.L. VHF antennas for radio communications with mobile objects, broadcasting and television. - M .: Radio and communications, 1997) and is formed by the connection of three broadband quadrature 3 dB of bridge devices 17 and two wideband phase shifters 18 with a 90 ° phase advance. As a result, at the outputs 13, 14, 15, 16, amplitude-phase distributions are formed corresponding to the normalized vector of complex stress amplitudes [1, -i, -1, i], [-i, 1, i, -1], [- i, 0, -i, 0], [0, -i, 0, -i] (where i is the imaginary unit) when applying signals to the inputs 9, 10, 11, 12 of the beam-forming device, respectively.

Broadband omnidirectional ring antenna array operates as follows.

When signals are fed to the inputs of the frequency separation devices, emitters connected to their outputs are excited, and in the low-frequency part of the low-frequency range, mainly emitters of the low-frequency range are excited, in the high-frequency part of the high-frequency range, mainly emitters of the high-frequency range, and in the region of partial overlapping of the ranges, both other emitters. In this case, directivity characteristics are formed, determined by the amplitude-phase distribution of signals. The choice of the optimal geometric dimensions of the emitters and the grating as a whole, as well as the frequency characteristics of the frequency separation devices, ensures that the radiation characteristics of the grating are close to omnidirectional, for various amplitude-phase distributions of signals, including in the region of partial overlapping of frequency ranges.

In a variant of a broadband omnidirectional ring antenna array excited through a beam-forming device, when a signal is supplied to the first input (9 in Fig. 4), emitters (pairs of emitters in the region of partial overlapping of frequency ranges) are excited quadrature, with a phase shift between adjacent emitters (pairs of emitters) + 90 °, when applying a signal to the second input (10 in Fig. 4), emitters (pairs of emitters) are excited quadrature, with a phase shift between adjacent emitters (pairs of emitters) -90 °, when applying a signal to the second input (11 in Fig. 4) are excited in phase by two opposite emitters (pairs of emitters), and the other two emitters (pairs of emitters) are not excited, when a signal is supplied to the fourth input (12 in Fig. 4), the other two emitters are excited in phase (pairs emitters), and the remaining two emitters (pairs of emitters) are not excited. Thus, the formation of up to four independent radiation patterns that are close to circular in the horizontal plane is realized.

In FIG. 6 ... 8 shows the calculated radiation patterns in the horizontal plane for a particular version of the 8-element array, designed to operate in the frequency band 100 ... 520 MHz. The low-frequency range 100 ... 260 MHz and the high-frequency range 200 ... 520 MHz overlap in the frequency band 200 ... 260 MHz, i.e. the bandwidth of the overlapping frequencies of the high-frequency and low-frequency ranges in this case is 14% of the width of the working frequency band of the grating.

At a frequency of 100 MHz (FIG. 6), mainly low-frequency emitters are excited, at a frequency of 230 MHz (FIG. 7) both low-frequency and high-frequency emitters are excited, and at a frequency of 520 MHz (FIG. 8), mainly high-frequency emitters are excited.

The solid curves in FIG. 6 ... 8 correspond to in-phase excitation of all four inputs, dashed - to quadrature excitation of four inputs, and dashed - to in-phase excitation of two opposite inputs (the other two are not excited).

The calculation results confirm the achievement of the goal - the expansion of the operating frequency band, since the quasi-circular shape of the radiation patterns with acceptable unevenness (no worse than ± 4 dB) under in-phase and quadrature excitation modes is provided in the entire frequency band, including the region of partial overlap of the high-frequency and low-frequency ranges, and at in-phase excitation of two opposite emitters - for the most part of the indicated frequency band, with the exception of a relatively small portion in the upper their high-frequency frequencies.

Claims (6)

1. A method of transmitting signals through an omnidirectional ring log periodic periodic antenna array of vertical polarization, based on dividing the full working frequency band of the antenna into the first and second transmission frequency ranges, allocating an omnidirectional ring antenna array for each of the transmission ranges of its sections, assigning the transmitted channel signals with a dedicated transmission frequency, the allocation of assigned transmission channels to transmission ranges in accordance with the allocated transmission frequency and transmission the antenna signals at the selected transmission frequencies through the corresponding sections of the antenna array, while the sections of the first transmission range are located between the sections of the second transmission range, and when dividing the full working frequency band into the first and second transmission frequency ranges, these transmission frequency ranges are assigned with partial overlap of the transmission bands of the first and the second transmission frequency ranges and signals falling into the overlapping frequency zone of these two transmission frequency ranges and having matching allocated frequencies n Transmissions, transmit on both transmission ranges through all sections of the antenna array. 2. The method according to p. 1, characterized in that they use an eight-section omnidirectional antenna with four sections for each range, while the signals at the inputs of adjacent 1st, 2nd, 3rd and 4th elements in each section are offset relative to each other at + 90 °. 3. The method according to p. 1, characterized in that they use an eight-section omnidirectional antenna with four sections for each range, while the signals at the inputs of adjacent 1st, 2nd, 3rd and 4th elements in each section are offset relative to each other at -90 °. 4. The method according to p. 1, characterized in that they use an eight-section omnidirectional antenna with four sections for each range, while the signals at the inputs of two opposite section elements are formed in-phase, and the orthogonal elements do not excite them. 5. Broadband omnidirectional ring log periodic periodic antenna array of vertical polarization, containing emitters evenly spaced on the central support, as emitters, sections of vertical periodic polarization log antenna are arranged in two groups of sections, one group of sections of the antenna array is configured to operate in the high-frequency transmission range, and another group of antenna array sections is configured to operate in the low-frequency transmission range, partially overlap we have a high-frequency transmission range of the aforementioned group of sections, while the sections of the emitters of both groups are located in the same plane so that the sections of the emitters of one group are located between the sections of the emitters of the other group, while the emitters of both groups operating in the overlapping frequency range are connected to frequency separation devices providing separation of the low-frequency and high-frequency ranges with a partial overlap of these transmission ranges, with each frequency distribution device o has one input and two outputs, so that the outputs of each frequency-separating devices are connected corresponding inputs of two adjacent radiators, and inputs the frequency-dividing devices are interfaces array antenna for transmitting / receiving a signal. 6. The omnidirectional ring antenna array according to claim 5, characterized in that it is equipped with eight sections of emitters and four interfaces, while the inputs of the sections of the array are connected to the interfaces of the antenna array through a beam-forming device capable of providing the normalized vector of complex voltage amplitudes at the inputs of the array [ 1, -i, -1, i], [1, i, -1, -i], [1, 0, 1, 0], [0, 1, 0, 1] for the 1st, 2nd , 3rd and 4th modes, respectively, where i is the imaginary unit.

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