JP2008219175A - Power synthesizing/distributing device and multi-point power feed circularly polarized wave antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a power synthesizing device with a simple configuration capable of improving isolation characteristics in a state where a plurality of transmission lines receiving inputted power have the same impedance and a phase difference is 90°. <P>SOLUTION: This power synthesizing device has a distribution coupling type directional coupler consisting of a main line and a sub-line electromagnetically coupled to the main line; first and second transmission lines connected to both ends of the main line; and third and fourth transmission lines connected to both ends of the sub-line. The device synthesizes the input power from the second transmission line connected to the main line and the third transmission line connected to the sub-line to the first transmission line connected to the main line, wherein a 1/4 wavelength transformer having characteristic impedance different from that of the first transmission line is inserted into the first transmission line connected to the main line. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power synthesizing / distributing device that combines or distributes power with improved isolation characteristics between a plurality of transmission lines to which power is input or between a plurality of transmission lines to which power is output, and the power The present invention relates to a multi-point feed circularly polarized antenna including a synthesizer / distributor.

  In general, a circuit such as a directional coupler is widely used to combine power. In particular, a power combiner 10 using a distributed coupling type directional coupler 17 as shown in FIG. 10 is frequently used. The power combiner 10 includes a distributed coupling type directional coupler 17 including a main line 11 and a sub-line 12 electromagnetically coupled to the main line 11. The main line 11 includes a first transmission line 13 and a second transmission line. A third transmission line 15 and a fourth transmission line 16 are connected to the line 14 and the sub line 12. A termination resistor is connected to the fourth transmission line 16. For example, when power is input from the second transmission line 14 and the third transmission line 15, these powers are combined and output to the first transmission line 13.

  Here, in the directional coupler referred to as such a distributed coupling type, the characteristic can be expressed by using impedances Zeven and Zodd in which the symmetry plane of the directional coupler is an even mode and an odd mode. In this type of directional coupler, 3 dB, that is, a relatively large number of input impedances in the second transmission line 14 and the third transmission line 15 are generally used. In theory, Zeven and Zodd are appropriately used. If a proper value is selected, the reflection characteristic (S11) and the isolation characteristic (S32) can be made extremely small. However, in order to actually set Zeven and Zodd to such values, the degree of coupling and phase of the two lines becomes a problem, so in general products that are commercialized, both reflection characteristics and isolation characteristics are at most − It is about 20 dB. Therefore, here, the values of Zevne and Zodd are selected to be 150 dB and 25 dB, respectively.

  The characteristics (scattering matrix) at this time are shown in FIG. The horizontal axis represents frequency and the vertical axis represents gain. As can be seen from FIG. 11, at the desired frequency (1.5 GHz), S21 and S31 are equal. This indicates that the input impedances of the second transmission line 14 and the third transmission line 15 are equal. Further, the reflection characteristic and the isolation characteristic are both about −20 dB at most, and it is required to improve the isolation characteristic with a simple configuration.

Therefore, Patent Document 1 discloses a power combiner 20 that can improve isolation characteristics. As shown in FIG. 12, the power combiner 20 is provided with impedance matching circuits 21 a and 21 b on a part of the sub line 12 in the power combiner 10 described above. Therefore, impedance matching between the third transmission line 15 and the fourth transmission line 16 can be easily performed, and the impedance of the third transmission line 15 connected to a predetermined circuit network or the like is set to a desired value. can do. Therefore, it is possible to reduce the high-frequency signal flowing out to the fourth transmission line 16 and improve the isolation characteristics.
JP 2002-280812 A

  By the way, in order to satisfactorily receive the circularly polarized wave transmitted from a satellite or the like, the transmission line of the power combiner connected to each feeding point of the multipoint feeding circularly polarized antenna has a phase difference of 90 °. It is required that the impedance is equal.

  However, since the power combiner 20 described in Patent Document 1 changes the impedance on the third transmission line 15 side to a predetermined value in order to improve the isolation characteristic, the impedance of the second transmission line 14 and the third transmission line 15 is changed. Will be different. Furthermore, when the impedance matching circuits 21a and 21b are connected, the phase changes at that portion. That is, the phase difference between the second transmission line 14 and the third transmission line 15 deviates from the original 90 °. Therefore, although the above-described power combiner 20 has improved isolation characteristics, there is a problem that it is not suitable for use in a multipoint feed circularly polarized antenna or the like.

  The present invention has been made in view of such problems, and improves the isolation characteristics with a simple configuration in which the impedance of a plurality of transmission lines to which power is input is equal and the phase difference is 90 °. An object of the present invention is to realize a power combiner that can be used. In particular, an object of the present invention is to provide a circularly polarized antenna that is suitable for mounting on a feeder circuit such as a multipoint fed circularly polarized antenna and that is less susceptible to multipath.

  In order to solve the above-described problem, a power combiner according to the present invention includes a distributed coupling type directional coupler including a main line and a sub line that is electromagnetically coupled to the main line, and a first connected to both ends of the main line. And a second transmission line and third and fourth transmission lines connected to both ends of the sub line, and an input from the second transmission line connected to the main line and the third transmission line connected to the sub line Power is combined with the first transmission line connected to the main line for output, or input power from the first transmission line connected to the main line is connected to the second transmission line and the sub line connected to the main line. A quarter-wave transformer having a characteristic impedance different from that of the first transmission line is inserted into the first transmission line connected to the main transmission line and output to the third transmission line to be connected. .

  In the power combiner described above, the quarter wavelength transformer may be replaced with an open-ended stub and a high impedance line, or a lumped constant circuit element.

  Furthermore, in order to solve the above-mentioned problem, a multi-point feed circularly polarized antenna having a plurality of feed points and receiving circularly polarized waves according to the present invention comprises a main line and a sub line that is electromagnetically coupled to the main line. Consisting of a distributed coupling type directional coupler, first and second transmission lines connected to both ends of the main line, and third and fourth transmission lines connected to both ends of the sub-line, connected to the main line Input power from the third transmission line connected to the second transmission line and the sub-line is combined and output to the first transmission line connected to the main line, and to the first transmission line connected to the main line The first transmission line includes at least one power combiner in which a quarter-wave transformer having a different characteristic impedance is inserted.

  For example, a two-point feed circularly polarized antenna having two feed points and receiving circularly polarized waves includes a first transmission line connected to one end of the main line and a second transmission line connected to the other end of the main line. A transmission line; a third transmission line connected to one end of the sub-line that is electromagnetically coupled to the main line; and a fourth transmission line connected to the other end of the sub-line. The first transmission line is connected to the internal network of the two-point feed circularly polarized antenna, and the second transmission line and the third transmission line are connected to the two feed points, respectively. The fourth transmission line is connected to a terminating resistor, and a quarter-wave transformer having a characteristic impedance different from that of the first transmission line is inserted into the first transmission line.

  For example, a four-point feed circularly polarized antenna that has four feed points and receives circularly polarized waves includes a first transmission line connected to one end of the main line and a second transmission line connected to the other end of the main line. A transmission line; a third transmission line connected to one end of the sub-line that is electromagnetically coupled to the main line; and a fourth transmission line connected to the other end of the sub-line. A first power synthesizer to a third power synthesizer, wherein the first transmission line provided in the first power synthesizer is connected to an internal network of the four-point-feed circularly polarized antenna, The second transmission line and the third transmission line included in the power combiner are connected to the first transmission line included in the second power combiner and the third power combiner, respectively, and the second power combiner And the second transmission line provided in the third power combiner and the The three transmission lines are connected to the four feeding points, respectively, the fourth transmission line included in the first power combiner to the third power combiner is connected to a terminating resistor, and the first power combiner to the A quarter-wave transformer having a characteristic impedance different from that of the first transmission line is inserted into at least one of the first transmission lines provided in the third power combiner.

  According to the present invention, based on the general-purpose distributed coupling type directional coupler, the isolation characteristics can be obtained in a state where the impedances of a plurality of transmission lines to which power is input or output are equal and the phase difference is 90 °. An improved power combining / distributing device can be easily realized. In particular, it is suitable for mounting on a feeding circuit such as a multipoint feeding circularly polarized antenna, and can be made less susceptible to multipath.

(Embodiment 1)
Hereinafter, power combining apparatus 100 according to Embodiment 1 of the present invention will be described with reference to FIG.

  The power combiner 100 according to the first embodiment includes a quarter wavelength transformer 1, a distributed coupling type directional coupler 17 including a main line 11 and a subline 12 electromagnetically coupled to the main line 11, a first The transmission line 13, the second transmission line 14, the third transmission line 15, and the fourth transmission line 16 are configured. The first transmission line 13 and the second transmission line 14 are connected to the main line 11, and the third transmission line 15 and the fourth transmission line 16 are connected to the sub line 12. Here, the 1st transmission line 13 and the 3rd transmission line 15 are connected to the same side (left side in FIG. 1) of the main line 11 and the subline 12, respectively. Further, a resistor is mainly connected to the fourth transmission line 16, and in particular, a termination resistor is connected.

  The quarter wavelength transformer 1 is inserted in the first transmission line 13. By configuring a part of the first transmission line 13 with the quarter wavelength transformer 1 having a characteristic impedance different from that of the first transmission line 13, the isolation characteristics of the distributed coupling type directional coupler 17 and the like Can be further improved.

  Here, FIG. 2 shows a simulation result when the impedance of the quarter-wave transformer 1 provided is 60Ω. The distributed coupling type directional coupler 17 is the same as that used in the power combiner 10 shown in the background art. The horizontal axis represents frequency and the vertical axis represents gain. FIG. 2 shows that the isolation characteristic in the desired frequency band (1.5 GHz) is improved to about −22 dB. Also, the reflection characteristic is greatly improved to about -40 dB. As in the case of the conventional power combiner 10, S21 and S31 are equal, and the second transmission line 14 and the third transmission line 15 remain symmetrical, and the phase difference is 90 °. .

  Therefore, the power combiner 100 can be used as a power combiner circuit for a two-point-feed circularly polarized antenna in which the phase difference between the transmission lines connected to each feed point is 90 ° and the impedance is required to be equal. . Hereinafter, the flow of power when the two-point-feed circularly polarized antenna receives radio waves will be described.

  Each feeding point of the two-point feeding circularly polarized antenna is connected to the second transmission line 14 and the third transmission line 15 of the power combiner 100, respectively. The first transmission line 13 is connected to a network or the like where the combined power is to be processed, and the fourth transmission line 16 is connected to a termination resistor. Here, when circularly polarized waves are received from a positioning satellite or the like, power is input to the second transmission line 14 and the third transmission line 15 from each feeding point. At this time, since the phase difference between the second transmission line 14 and the third transmission line 15 is 90 °, it is possible to input electric power immediately upon receiving circularly polarized waves. Furthermore, since the impedances of the second transmission line 14 and the third transmission line 15 are equal, the input power is also equal.

  The main line 11 is electromagnetically coupled to the sub line 12, and the power input from the second transmission line 14 and the power input from the third transmission line 15 are combined and output from the first transmission line 13. . The combined power is subjected to predetermined processing in a circuit network or the like connected to the first transmission line 13.

  Here, instead of the quarter-wave transformer 1, two open termination stubs 2 a and 2 b and a high impedance line 3 can be used. Specifically, as shown in FIG. 3, a part of the first transmission line 13 may be a high impedance line 3, and the terminal open stubs 2 a and 2 b may be connected to both ends thereof. The simulation result at this time is shown in FIG. FIG. 4 shows that the isolation characteristic is improved to about −32 dB in the desired frequency band (1.5 GHz). It can also be seen that the reflection characteristics are improved to about -25 dB. As in the case of the conventional power combiner 10, S21 and S31 are equal, and the second transmission line 14 and the third transmission line 15 remain symmetrical, and the phase difference is 90 °. .

  As described above, the isolation characteristic and the reflection characteristic can be improved as compared with the conventional one by substituting the quarter-wave transformer with a terminal open stub and a high impedance line. Furthermore, it is possible to realize a power combiner that is smaller than when a quarter-wave transformer is used. Further, if the quarter wavelength transformer is replaced with a lumped constant circuit element such as a capacitor or an inductor, the size can be further reduced.

  With the above configuration, based on a general-purpose distributed coupling directional coupler, the isolation characteristics are improved when the impedance of multiple transmission lines to which power is input is equal and the phase difference is 90 ° It is possible to easily realize the power combining apparatus. In particular, it is suitable for mounting on a feeding circuit such as a two-point feeding circularly polarized antenna, and can be made less susceptible to multipath effects.

(Embodiment 2)
Hereinafter, power combining apparatus 200 according to Embodiment 2 of the present invention will be described with reference to FIG. Note that the description of the same configuration as that of Embodiment 1 is omitted.

  The power combiner 200 is composed of three power combiners 200a, 200b and 200c. Specifically, the first transmission line 13b of the power combiner 200b is connected to the second transmission line 14a of the power combiner 200a, and the first transmission line 13c of the power combiner 200c is the third transmission line of the power combiner 200a. 15a. Further, each of the power combiners 200a, 200b, and 200c has the same configuration as that of the power combiner 100 in the first embodiment, and the quarter-wave transformers 1a, 1b are respectively added to the first transmission lines 13a, 13b, and 13c. And 1c are inserted.

  A simulation result in this configuration is shown in FIG. The horizontal axis represents frequency and the vertical axis represents gain. As shown in FIG. 6, S21, S31, S41 and S21 are all equal in a desired frequency band (1.5 GHz). This indicates that the input impedances of the second transmission lines 14b and 14c and the third transmission lines 15b and 15c of the power combiners 200b and 200c are equal. It can also be seen that the isolation characteristics of the power combiners 200a, 200b and 200c are improved to about −50 dB, respectively. It can also be seen that the reflection characteristics are improved to about -50 dB. The second transmission lines 14a, 14b, and 14c and the third transmission lines 15a, 15b, and 15c remain symmetrical, and their respective phase differences are 90 °.

  Therefore, the power combiner 200 can be used as a power combiner circuit for a four-point fed circularly polarized antenna that is required to have a phase difference of 90 ° and equal impedance. Hereinafter, the flow of power when the four-point-feed circularly polarized antenna receives radio waves will be described.

  Each feed point of the four-point feed circularly polarized antenna is connected to the second transmission line 14b and the third transmission line 15b of the power combiner 200b, and the second transmission line 14c and the third transmission line 15c of the power combiner 200c, respectively. Has been. In addition, the first transmission line 13a of the power combiner 200a is connected to a network or the like where the combined power is to be processed, and the fourth transmission lines 16a, 16b, and 16c are connected to a termination resistor.

  When circularly polarized waves are received from a positioning satellite or the like, electric power is input from the feed points to the second transmission lines 14b and 14c and the third transmission lines 15b and 15c, respectively. At this time, since the phase difference between each of the second transmission lines 14b and 14c and the third transmission lines 15b and 15c facing each other is 90 °, it is possible to input electric power immediately upon receiving circularly polarized waves. Furthermore, since the impedances of the second transmission lines 14b and 14c and the third transmission lines 15b and 15c are configured to be equal, the input power is also equal.

  The main lines 11a, 11b and 11c are electromagnetically coupled to the sub lines 12a, 12b and 12c, respectively. Therefore, the electric power input through the third transmission lines 15a, 15b, and 15c flows to the main lines 11a, 11b, and 11c, respectively, and is combined with the electric power input from the second transmission lines 14a, 14b, and 14c. The combined power is output from the first transmission lines 13a, 13b, and 13c, respectively. Here, the first transmission lines 13b and 13c are connected to the second transmission line 14a and the third transmission line 15a, respectively. Accordingly, the power output from the first transmission line 13a is the sum of the powers input from the second transmission lines 14b and 14c and the third transmission lines 15b and 15c. And a predetermined process is performed in the network etc. which were connected to the 1st transmission line 13a.

  A power combiner 300 as shown in FIG. 7 can also be used. The power combiner 300 includes power combiners 300a and 300c similar to the power combiner 10 and a power combiner 300b similar to the power combiner 100 in the first embodiment. In addition, the connection method of each transmission line and the way of power flow when the four-point-feed circularly polarized antenna receives radio waves are the same as those of the power combiner 200.

  Here, the simulation result in this structure is shown in FIG. From FIG. 8, it can be seen that the isolation characteristics of the power combiners 300a, 300b, and 300c are improved to about −25 dB in a desired frequency band (1.5 GHz). Thus, even the power combiner 300 in which the quarter-wave transformer 1 is inserted only in the first transmission line 13b of the power combiner 300b can be used for a four-point feed circularly polarized antenna. Better characteristics can be obtained. In addition, the effect of this invention can be acquired even if the 1st transmission line in which a quarter wavelength transformer is inserted is any 1st transmission line.

  For reference, the phase characteristics of the power combiner 300 are shown in FIG. From FIG. 9, it can be seen that the phase difference between the plurality of transmission lines to which power is input is 90 ° at a desired frequency (1.5 GHz).

  As described above, the number of transmission lines that can be connected can be arbitrarily increased by using the power combiner in the present invention in combination (connected) rather than using it alone. Furthermore, the isolation characteristics can be further improved. The effect of the present invention can also be obtained by inserting a quarter-wave transformer into any one of a plurality of power combiners.

  Finally, it should be noted that reversibility is realized at high frequencies, and that the same effect can be obtained even if the input / output of the power described above is reversed. That is, the power transmission device that distributes the power input from the first transmission line to the second transmission line and the third transmission line and outputs the second transmission line has the same configuration as the power combining device in the present invention. The isolation characteristics can be improved when the impedances of the line and the third transmission line are equal and the phase difference is 90 °.

  Further, the distributed coupling type directional coupler may be an SMD (surface mounting component). By using SMD, cost reduction and size reduction can be further achieved. Further, the present invention can be similarly applied to an optical directional coupler using an optical waveguide.

1 is a schematic diagram of a power combiner according to Embodiment 1 of the present invention. It is a figure which shows the simulation result in the electric power synthesizing | combining apparatus by Embodiment 1 of this invention. It is the schematic when using a termination | terminus open stub and a high impedance line. It is a figure which shows the simulation result in the electric power synthesizing | combining apparatus when the structure in FIG. 3 is used. It is the schematic of the electric power synthesizing | combining apparatus by Embodiment 2 of this invention. It is a figure which shows the simulation result in the electric power synthesizing | combining apparatus by Embodiment 2 of this invention. It is the schematic of the electric power synthesizing | combining apparatus by Embodiment 2 of this invention. It is a figure which shows the simulation result in the electric power synthesizing | combining apparatus by Embodiment 2 of this invention. It is a figure which shows the simulation result in the electric power synthesizing | combining apparatus by Embodiment 2 of this invention. 1 is a schematic diagram of a general power combiner. It is a simulation result in a general power combiner. 1 is a schematic diagram of a power combiner described in Patent Document 1. FIG.

Explanation of symbols

1 1/4 wavelength transformer 2 open termination stub 3 high impedance line 10 power combiner 11 main line 12 subline 13 first transmission line 14 second transmission line 15 third transmission line 16 fourth transmission line 17 distributed coupling type Directional coupler 100 Power combiner 200 Power combiner 300 Power combiner

Claims (4)

A distributed coupling type directional coupler comprising a main line and a sub line electromagnetically coupled to the main line;
First and second transmission lines connected to both ends of the main line;
A third and a fourth transmission line connected to both ends of the sub-line,
The input power from the second transmission line connected to the main line and the third transmission line connected to the sub-line is combined and output to the first transmission line connected to the main line, or connected to the main line. In the power combiner / distributor for distributing and outputting the input power from the first transmission line to the second transmission line connected to the main line and the third transmission line connected to the sub line,
A power combiner / distributor, wherein a quarter-wave transformer having a characteristic impedance different from that of the first transmission line is inserted into the first transmission line connected to the main line. The power combiner / distributor of claim 1.
A power combiner / distributor, wherein the quarter-wave transformer is replaced by an open-ended stub and a high impedance line. The power combiner / distributor of claim 1.
A power combiner / distributor, wherein the quarter-wave transformer is replaced with a lumped constant circuit element. In a multi-point feed circularly polarized antenna having a plurality of feed points and receiving circularly polarized waves,
A distributed coupling type directional coupler comprising a main line and a sub line electromagnetically coupled to the main line;
First and second transmission lines connected to both ends of the main line;
The third and fourth transmission lines connected to both ends of the sub-line,
While combining and outputting the input power from the second transmission line connected to the main line and the third transmission line connected to the sub line to the first transmission line connected to the main line,
A multipoint feed circular bias characterized by comprising at least one power combiner in which a first wavelength transformer having a characteristic impedance different from that of the first transmission line is inserted in the first transmission line connected to the main line. Wave antenna.

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