JP4049968B2 - Antenna duplexer and wireless communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna duplexer that can use one antenna for both transmission and reception.
[0002]
[Prior art]
Reference 1: Japanese Patent Application Laid-Open No. 59-232 (airline duplexer)
Reference 2: JP-A-48-33753 (Transmission / Reception Shared Antenna System)
A cellular phone or other wireless communication device employs a configuration in which one antenna mounted on the telephone body is shared for transmission and reception. It is an antenna duplexer that makes it possible to share such an antenna. Conventionally, the configuration shown in FIGS. 2 and 3 has been used. Here, FIG. 2 is an example of the antenna duplexer disclosed in Document 1, and FIG. 3 is an example of the antenna duplexer disclosed in Document 2.
[0003]
A conventional example will be briefly described. The antenna duplexer shown in FIG. 2 suppresses the transmission signal transmitted from the transmitter 2 to the antenna 4 from being mixed into the receiver 3 via the circulator 1. An equalizer 8 is disposed between the two, and a signal component having the same amplitude and opposite phase as the signal component mixed through the circulator 1 is generated, and the mixed signal is canceled by the generated signal. On the other hand, the antenna duplexer shown in FIG. 3 couples a transmission feed line and a reception feed line shallowly via directional couplers 27 and 28 and circulates via a circulator 26. A configuration is adopted in which (solid line) is canceled by an interference wave (broken line) having the same amplitude and opposite phase.
[0004]
[Problems to be solved by the invention]
However, the conventional techniques described above have the following technical problems.
[0005]
(1) The circuit scale becomes very large. For this reason, the enlargement of an apparatus cannot be avoided.
[0006]
(2) It is easily affected by characteristic changes such as filters. For example, since it reacts sensitively to environmental changes such as temperature fluctuations, the characteristics are not stable.
[0007]
The present invention has been made in consideration of the above problems, and solves the above technical problem so that the reflected wave from the antenna end of the transmission signal and the leakage wave through the circulator of the transmission signal are not mixed into the reception system. The purpose is to propose an antenna duplexer that can be suppressed.
[0008]
[Means for Solving the Problems]
(A) In order to solve such a problem, in the first invention, an antenna duplexer for sharing one antenna between a transmission system and a reception system has the following configuration.
[0009]
That is, (1) a first terminal that inputs a transmission signal from a transmission apparatus, a second terminal that inputs a reception signal from an antenna and outputs a transmission signal to the antenna, and outputs a reception signal to the reception apparatus A circulator having a third terminal and having isolation between the first terminal and the third terminal; and (2) provided between the second terminal of the circulator and the feeder line terminal of the antenna. And a standing wave adjuster capable of changing the phase and magnitude of reflection. Furthermore, the standing wave regulator includes a reflected wave transmission signal reflected by the antenna, and the phase to cancel both the leaky waves of the transmitted wave from the first terminal is mixed to the third terminal through the circulator to generate a unique reflected wave having an amplitude, but optional adjustable impedance.
[0010]
By adopting such a configuration, not only the transmission signal component mixed from the transmission device via the circulator to the reception device side but also the transmission signal component reflected by the antenna end and mixed into the reception device side via the circulator can be suppressed. Therefore, it is possible to realize an antenna duplexer that is easy to downsize and stable against temperature fluctuations.
[0011]
(B) In the second invention, an antenna duplexer for sharing one antenna between a transmission system and a reception system is provided with the following configuration.
[0012]
That is, (1) a first terminal that inputs a transmission signal from a transmission apparatus, a second terminal that inputs a reception signal from an antenna and outputs a transmission signal to the antenna, and outputs a reception signal to the reception apparatus A circulator having a third terminal and having isolation between the first terminal and the third terminal, and (2) provided near the feeder terminal of the antenna, and the phase and magnitude of the reflected wave A first standing wave adjuster capable of varying the thickness; and (3) provided between the second terminal of the circulator and the first standing wave adjuster so that the phase and magnitude of the reflected wave can be varied. A second standing wave regulator. Furthermore, the first standing wave regulator, as the transmission signal to generate a unique reflected wave and a so that phase and amplitude reduces the reflected wave reflected by the antenna, optionally adjustable impedance It is a thing. The second standing wave adjuster cancels the reflected wave of the transmission signal reflected by the antenna together with the first standing wave adjuster, and mixes into the third terminal from the first terminal via the circulator. to generate a unique reflected wave with the phase and amplitude to cancel both the wave leaky wave, but any adjustable impedance.
[0013]
By adopting such a configuration, not only the transmission signal component mixed from the transmission device via the circulator to the reception device side but also the transmission signal component reflected by the antenna end and mixed into the reception device side via the circulator can be suppressed. Therefore, it is possible to realize an antenna duplexer that is easy to downsize and stable against temperature fluctuations. Moreover, even when the electrical length between the antenna and the circulator has to be increased by dividing the standing wave regulator into two first and second standing wave regulators, one standing wave adjustment is possible. It is possible to reduce the influence of the reflected wave from the antenna end that cannot be suppressed by the device alone.
[0014]
(C) In the third invention, the antenna duplexer described in the first or second invention is provided between the transmission device, the reception device, and the antenna. With this configuration, it is possible to realize a wireless communication device that is small and stable against temperature fluctuations.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(A) First Embodiment Hereinafter, a first embodiment of an antenna duplexer and a wireless communication device according to the present invention will be described. FIG. 1 shows the overall configuration of a wireless communication device on which an antenna duplexer is mounted.
[0016]
In FIG. 1, only functional blocks related to wireless communication are shown, and descriptions of other functional blocks are omitted. Therefore, if the wireless communication device is an information communication terminal including a communication antenna, an input device such as a liquid crystal display device or a keyboard is provided in addition to the functional blocks shown in the figure, and a mobile phone may be used. In this case, a liquid crystal display unit, operation buttons, and the like are provided.
[0017]
Returning to the description of FIG. The wireless communication device includes an antenna duplexer 51, a transmission device 52, a transmission filter 53, an antenna 54, a reception device 55, and a reception filter 56. Among these, the transmission filter 53 is a filter provided to suppress unnecessary side wave components in the transmission radio wave. The reception filter 56 is a filter provided to pass only a desired radio wave in the reception signal.
[0018]
On the other hand, the antenna duplexer 51 which is a characteristic part of the embodiment of the present application includes a circulator 51A and a standing wave adjuster 51B.
[0019]
Here, the circulator 51A outputs a transmission signal to the first terminal a that inputs a transmission signal from the transmission device 52 and the antenna 54, and a second terminal b that inputs a reception signal from the antenna 54. And a third terminal c that outputs a reception signal to the reception device 55.
[0020]
The circulator 51A functions as an isolator that prevents radio waves input to the first terminal a from appearing at the third terminal c. However, as has been a problem in the past, there is a limit to the function as an isolator for a microwave band signal, and actually leakage waves Yk are mixed from the transmission system to the reception system.
[0021]
The standing wave regulator 51B is a component unique to the present embodiment, and is provided between the second terminal b of the circulator 51A and the feeder line terminal of the antenna 54. The standing wave adjuster 51B generates an arbitrary impedance. By adjusting the impedance, the reflected wave and the leaky wave at the antenna end can be canceled by the reflected wave unique to the adjuster. .
[0022]
Hereinafter, a transmission / reception operation of a wireless communication device equipped with the antenna duplexer 51 having such a configuration will be described. First, the basic operation will be described. A transmission signal from the transmission device 52 is input to the first terminal a of the circulator 51A through the transmission filter 53. This transmission signal is supplied to the antenna 54 from the second terminal b of the circulator 51A through the standing wave adjuster 51B. On the other hand, the received signal received by the antenna 54 is input to the terminal b of the circulator 51A through the standing wave adjuster 51B. The input reception signal is guided to the reception filter 56 from the third terminal c of the circulator 51 </ b> A, and then input to the reception device 55.
[0023]
The above is the most basic operation that the antenna duplexer 51 assumes. Next, operations unique to the antenna duplexer 51 of the present embodiment will be described. In general, the circulator 51A reduces the transmission signal component mixed from the transmission system to the reception system, but cannot completely eliminate it. For this reason, it is inevitable that a leakage wave is mixed from the transmission system to the reception system at the third terminal c of the circulator 51A.
[0024]
Similarly, the antenna 54 is designed to reduce the transmitted signal component reflected by itself, but cannot be eliminated at all. For this reason, it is inevitable that a reflected wave enters the third terminal c of the circulator 51A from the antenna end toward the reception system.
[0025]
Therefore, the standing wave regulator 51B functions. The standing wave adjuster 51B can generate an arbitrary impedance as described above, and can change the phase and amplitude of the reflected wave. Although several methods are conceivable, in the present embodiment, in order to change the phase and the magnitude of reflection, a structure in which three variable length stubs are provided at appropriate intervals on the line is used. Here, the interval between the three stubs is set to 1/6 of the wavelength.
[0026]
However, the number of stubs is not limited to three, and may be two or four or more. In general, the adjustment becomes easier as the number increases. Further, the stub does not need to be fixed, and may be configured to be movable, to use a dielectric stub, or to be configured with a coupler and a variable short circuit.
[0027]
By adjusting the line width and the stub length of the variable-length stub, the standing wave adjuster 51B allows the synthesized wave Γ ^ of its own reflected wave Γt and the reflected wave Γa at the end of the antenna to be isolated from the circulator 51A Nevertheless, the adjustment is made so as to cancel the leakage wave Yk mixed from the transmission system to the reception system.
[0028]
Here, the adjustment amount is determined according to the wavelength λ of the transmission signal output from the transmission device 52. That is, the reflected waves Γt and Γa, their combined wave Γ ^, and the leaky wave Yk are determined so as to satisfy the following relationships (1) to (3).
[0029]
Γt = α · exp {-j (4πlt / λ + β)} (1)
Γa = γ · exp {-j (4π (lt + la) / λ} (2)
Γ ^ = Γt + Γa = −Yk (3)
Here, the reflected waves Γt and Γa, the synthesized wave Γ ^, and the leakage wave Yk are all vector quantities.
[0030]
The reflection magnitude α and the phase β are adjustable values, and the reflection magnitude γ is a fixed value. Furthermore, lt is the electrical length between the circulator 51A and the standing wave regulator 51B, la is the electrical length between the standing wave regulator 51B and the antenna 54, and lt is the center of the standing wave regulator 51B. This is the electrical length from the point to the confluence of circulator 51A.
[0031]
Incidentally, regarding these electrical lengths, the sizes of the circulator 51A, the standing wave regulator 51B, and the antenna 54 do not become a problem, and they can be handled as having no phase change in each element.
[0032]
As shown in the equations (1) to (3), the reflected waves Γt and Γa, the combined wave Γ ^, and the leaked wave Yk are all generated due to the transmission signal (wavelength λ). Therefore, by adjusting the phase β and the magnitude of reflection Γt in the standing wave adjuster 51B, a composite wave Γ ^ = − Yk that cancels the leakage wave Yk can be created.
[0033]
Thus, at the third terminal c of the circulator 51A, the leakage wave Yk is suppressed by the combined wave Γ ^ (= −Yk) input from the third terminal c, and the received signal received by the antenna 54 is received. Only the signal is supplied to the receiving device 55 via the reception filter 56.
[0034]
As described above, by using the antenna duplexer 51 having the configuration according to the present embodiment, it is possible to suppress both the leakage wave Yk from the transmission system mixed with the received signal and the reflected wave Γa from the antenna end, and a small size. This makes it possible to realize an antenna duplexer that is easy to make and stable against temperature fluctuations.
[0035]
As a result, the requirements regarding the performance of the antenna 54 and each filter can be relaxed, and the cost reduction of these parts can be promoted. This leads to a reduction in the cost of the wireless communication device.
[0036]
As a result, since a predetermined transmission / reception separation can be obtained even if the frequency detuning of the transmission signal and the reception signal is reduced, effective use of the frequency can be realized.
[0037]
(B) Second Embodiment Subsequently, a second embodiment of the antenna duplexer and the wireless communication device according to the present invention will be described. FIG. 4 shows the overall configuration of a wireless communication device on which the antenna duplexer is mounted. 4 shows the same parts as those in FIG. 1 with the same reference numerals, and only different parts are indicated with different reference numerals. A feature point of the second embodiment is that two standing wave regulators are prepared.
[0038]
This is due to the following reason. In general, an antenna and an antenna duplexer are usually arranged in the vicinity so that the line length connecting them becomes small. However, depending on the installed device configuration, the length of the line connecting the antenna and the antenna duplexer may have to be increased.
[0039]
In the case of the first embodiment, when the line length la connecting the antenna and the antenna duplexer becomes large, the phase variation of the reflected wave Γa with respect to the wavelength λ of the transmission signal is small as the line length la becomes small as apparent from the equation (2). Compared to the case, the frequency band that can be suppressed becomes narrower.
[0040]
Therefore, in the second embodiment, the first standing wave regulator 51B1 having the function of canceling the reflected wave Γa from the antenna end and the second constant wave having the function of canceling the leakage wave Yk from the transmission system. It will be provided separately in two of the presence wave adjuster 51B2.
[0041]
In FIG. 4, the first standing wave regulator 51B1 is disposed in the vicinity of the antenna, and the line portion connecting the first standing wave regulator 51B1 and the second standing wave regulator 51B2 is the first embodiment. It functions as a line connecting the antenna and the antenna duplexer.
[0042]
Here, in order to reduce the sensitivity to frequency, the first standing wave adjuster 51B1 is arranged as close as possible to the antenna 54, and similarly the second standing wave adjuster 51B2 is arranged as close as possible to the circulator 51A. And
[0043]
Returning to the description of FIG. In the first standing wave regulator 51B1, the reflected wave Γt1 generated by the first standing wave regulator 51B1 cancels the reflected wave Γa from the antenna end at the input end of the second standing wave regulator 51B2. Adjusted to This adjustment amount is determined according to the wavelength λ of the transmission signal from the transmission device 52 and the characteristics of the line connecting the first standing wave adjuster 51B1 and the second standing wave adjuster 51B2.
[0044]
On the other hand, the second standing wave adjuster 51B2 is adjusted in the circulator 51A so that the reflected wave Γt2 generated by the second standing wave adjuster 51B2 cancels the leakage wave Yk mixed from the transmission system to the reception system. . This adjustment amount is determined according to the wavelength λ of the transmission signal from the transmission device 52.
[0045]
Thus, both the first standing wave adjuster 51B1 and the second standing wave adjuster 51B2 suppress both the reflected wave Γa from the antenna end and the leakage wave Yk from the transmission system. Only the signal is supplied to the receiving device 55 via the reception filter 56.
[0046]
As described above, by using the antenna duplexer 51 having the configuration according to the present embodiment, the leakage wave Yk from the transmission system mixed with the received signal and the antenna even when the line length to the antenna must be increased. It is possible to realize an antenna duplexer that can suppress both the reflected waves Γa from the ends, can be easily miniaturized, and is stable against temperature fluctuations.
[0047]
Thereby, the simplification of the apparatus arrange | positioned in the antenna vicinity or the freedom degree of antenna arrangement | positioning can be raised.
[0048]
Further, it is possible to relax the requirements regarding the performance of the antenna and the filter, promote the cost reduction thereof, reduce the frequency detuning of the transmission signal and the reception signal, and effectively use the frequency.
【The invention's effect】
(A) As described above, according to the first invention, in the antenna duplexer for sharing one antenna between the transmission system and the reception system, the first terminal for inputting the transmission signal from the transmission device, and the antenna Between the first terminal and the third terminal, and a second terminal for inputting the received signal from the antenna and outputting a transmission signal to the antenna, and a third terminal for outputting the received signal to the receiver. A circulator in which isolation is present, a standing wave adjuster that is provided between the second terminal of the circulator and the feed line terminal of the antenna and that can vary the phase and magnitude of reflection, and standing wave regulator includes a reflected wave transmission signal reflected by the antenna, the phase and amplitude as the first terminal counteract both the leaky wave of the transmission wave to be mixed to the third terminal through the circulator With unique To produce a reflected wave, by those optional adjustable impedance, not only the transmitted signal component that mixes into the receiving apparatus from the transmitting apparatus via the circulator, through the circulator is reflected at the antenna end A transmission signal component mixed on the receiving device side can be suppressed, and an antenna duplexer that can be easily miniaturized and is stable against temperature fluctuations can be realized.
[0050]
As a result, reception characteristics can be improved or performance characteristics required for antennas and filters can be relaxed.
[0051]
(B) According to the second invention as described above, in the antenna duplexer for sharing one antenna between the transmission system and the reception system, the first terminal for inputting the transmission signal from the transmission device; , Having a second terminal for inputting a reception signal from the antenna and outputting a transmission signal to the antenna, and a third terminal for outputting the reception signal to the receiving device, from the first terminal to the third terminal; A circulator in which there is isolation between the antenna, a first standing wave regulator that is provided in the vicinity of the feed line terminal of the antenna and can change the phase and magnitude of the reflected wave, the second terminal of the circulator, and the above A second standing wave adjuster provided between the first standing wave adjuster and capable of varying a phase and a magnitude of the reflected wave; and further, the first standing wave adjuster includes: , Ru reduces reflected wave transmission signal reflected by the antenna To generate a unique reflected wave having a phase and an amplitude cormorants, along with those optional adjustable impedance, the second standing wave regulator reflected wave transmission signal reflected by the antenna With a phase and amplitude that cancels both the first standing wave adjuster and the leakage wave of the transmission wave mixed into the third terminal from the first terminal via the circulator to produce a reflected wave, by those optional adjustable impedance, not only the transmitted signal component that mixes into the receiving apparatus from the transmitting apparatus via the circulator, through the circulator is reflected at the antenna end Thus, it is possible to suppress a transmission signal component mixed into the receiving apparatus side, and to realize an antenna duplexer that can be easily downsized and is stable against temperature fluctuations. In addition, by dividing the standing wave regulator into two first and second standing wave regulators, even if the electrical length between the antenna and the circulator has to be increased, one standing wave adjustment is possible. It is possible to reduce the influence of the reflected wave from the antenna end that cannot be suppressed by the device alone.
[0052]
As a result, reception characteristics can be improved or performance characteristics required for antennas and filters can be relaxed. As a result, frequency detuning between the transmission signal and the reception signal can be reduced, and effective use of the frequency can be realized. In addition, it is possible to simplify the device arranged in the vicinity of the antenna and improve the degree of freedom of antenna arrangement.
[0053]
(C) Further, as described above, according to the third invention, the antenna duplexer according to the first or second invention is provided between the transmitting device, the receiving device, and the antenna, thereby reducing the size and temperature. A wireless communication device that is stable against fluctuations and the like can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an antenna duplexer and a wireless communication device according to a first embodiment.
FIG. 2 is a block diagram showing a configuration of a conventional example 1;
FIG. 3 is a block diagram showing a configuration of Conventional Example 2;
FIG. 4 is a block diagram showing an antenna duplexer and a wireless communication device according to a second embodiment.
[Explanation of symbols]
1, 26, 51A ... circulator, 2 ... transmitter, 3 ... receiver, 4, 54 ... antenna, 8 ... equalizer, 27, 28 ... hybrid circuit, 51 ... antenna duplexer, 52 ... transmitter, 53 ... Transmission filter, 55... Reception device, 56... Reception filter, 51B, 51B1, 51B2.

Claims (3)

In the antenna duplexer for sharing one antenna in the transmission system and the reception system,
A first terminal for inputting a transmission signal from the transmission device, a second terminal for inputting a reception signal from the antenna and outputting a transmission signal to the antenna, and a third terminal for outputting the reception signal to the reception device; A circulator having isolation between the first terminal and the third terminal;
It provided between the feed line terminal of the second terminal and the antenna of the circulator, and a standing wave regulator capable of varying the phase and magnitude of the reflected, the standing wave regulator transmit signal antenna A unique reflected wave having a phase and an amplitude that cancels both the reflected wave reflected at step 1 and the leakage wave of the transmission wave mixed into the third terminal from the first terminal via the circulator is generated. antenna duplexer, characterized in that way, those optional adjustable impedance. In the antenna duplexer for sharing one antenna in the transmission system and the reception system,
A first terminal for inputting a transmission signal from the transmission device, a second terminal for inputting a reception signal from the antenna and outputting a transmission signal to the antenna, and a third terminal for outputting the reception signal to the reception device; A circulator having isolation between the first terminal and the third terminal;
A first standing wave regulator that is provided in the vicinity of the feeder terminal of the antenna and that can change the phase and magnitude of the reflected wave;
A second standing wave adjuster provided between the second terminal of the circulator and the first standing wave adjuster, the phase and magnitude of the reflected wave being variable,
The first standing wave regulator above SL, as the transmission signal to generate a unique reflected wave and a so that phase and amplitude reduces the reflected wave reflected by the antenna, optionally adjustable impedance As well as
Upper Symbol second standing wave regulator of the reflected wave transmission signal reflected by the antenna, the first cancellation with standing wave regulator, and from the first terminal third through the circulator antenna sharing, characterized in that to produce a unique reflected wave with the phase and amplitude to cancel both the leaky wave of the transmission wave to be mixed into the terminal, but optional adjustable impedance vessel. A wireless communication device, wherein the antenna duplexer according to claim 1 or 2 is provided between a transmission device, a reception device, and an antenna.

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