JP2014131115A - High-frequency transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable selecting a propagation direction in a waveguide in supplying power to the waveguide from a transmission line with another configuration.SOLUTION: A high-frequency transmission line 10 includes a waveguide 20, a 90° hybrid line 30, first and second power-feeding probes 41 and 42, and a switch circuit 50. The waveguide 20 is a rectangular waveguide, and one end is a first port Port21 and the other end is a second port Port22. A first terminal Ph31 of the 90° hybrid line 30 is connected to the first power-feeding probe 41, and a second terminal Ph32 is connected to the second power-feeding probe 42. The first and second power-feeding probes 41 and 42 are disposed at a distance of λg/4 in the waveguide 20. The third and fourth terminals Ph33 and Ph34 of the 90° hybrid line 30 are selectively connected to a third port Port10 via the switch circuit 50.

Description

  The present invention relates to a high-frequency transmission line including a waveguide, and more particularly to a high-frequency transmission line that feeds a high-frequency signal in the middle of the waveguide and propagates in a predetermined direction.

  Conventionally, various high-frequency transmission lines that propagate high-frequency signals using a waveguide have been devised. When switching the propagation direction of a high-frequency signal in a high-frequency line using such a waveguide, a waveguide switch is generally used. The waveguide switch includes an opening for inputting and outputting a high-frequency signal on four side surfaces of a rectangular parallelepiped casing, and two waveguides curved at 90 ° in the casing. The waveguide switch switches a combination of two openings to be conducted by rotating the two waveguides. Thereby, the propagation direction of a high frequency signal is switched.

  In addition, when mode conversion is performed between a waveguide and a transmission line of another mode (for example, a microstrip line), a power feeding probe is inserted in the middle of the waveguide, and the power feeding probe has another mode. Connect the transmission line.

  For example, Patent Document 1 is a directional coupler using mode conversion between a microstrip line and a waveguide. The microstrip line and the waveguide are connected at one end to the microstrip line and guided at the other end. They are connected by a power supply probe (probe) inserted into the tube.

JP-A-6-132710

  However, when switching the propagation direction of a high-frequency signal in the waveguide and mode conversion between the waveguide and another transmission line are necessary, the above-described waveguide switch and conversion unit must be provided separately. . Therefore, it is not easy to reduce the size of the high-frequency transmission line.

  An object of the present invention is to form a high-frequency transmission line that performs switching of a propagation direction in a waveguide and mode conversion between the waveguide and another transmission line in a small size.

  The high-frequency transmission line of the present invention is characterized by the following configuration. The high-frequency transmission line includes first, second, and third ports, and includes a waveguide, a 90 ° hybrid line, first and second feeding probes, and a switch circuit. The waveguide includes a first port and a second port, and has a shape capable of propagating a high-frequency signal between these ports. The 90 ° hybrid line includes a first terminal, a second terminal, a third terminal, and a fourth terminal. In the 90 ° hybrid line, the high-frequency signal input from the third terminal or the fourth terminal is distributed to the first terminal and the second terminal and output with a 90 ° phase difference. In the 90 ° hybrid line, the phase relationship between the high-frequency signals output when the high-frequency signal is input from the third terminal and when the high-frequency signal is input from the fourth terminal is reversed. The first feeding probe has one end connected to the first terminal and the other end inserted into the waveguide. The second feeding probe has one end connected to the second terminal and the other end inserted into the waveguide. The first power supply probe and the second power supply probe are arranged between the odd multiples of 1/4 of the in-tube wavelength of the high frequency signal. The switch circuit selectively connects the third terminal and the fourth terminal to the third port.

  In this configuration, the switch circuit connects the third port to the third terminal according to the distance between the first feeding probe and the second feeding probe arranged in the waveguide and the structure of the 90 ° hybrid line. When connected to a terminal, the mode of phase synthesis of high-frequency signals is varied. Then, by changing the mode of this phase synthesis, it is possible to select whether to output a high frequency signal from the first port of the waveguide or to output a high frequency signal from the second port. In addition, since mode conversion between the waveguide and another transmission line is performed by the first power supply probe and the second power supply probe, it is not necessary to provide a part for mode conversion separately from the part for switching.

  In the high-frequency transmission line of the present invention, the 90 ° hybrid line has an electrical length in which each of the first terminal, the second terminal, the third terminal, and the fourth terminal is an odd multiple of 1/4 of the wavelength of the high-frequency signal. It consists of a structure connected by tracks.

  This configuration shows a specific structure example of a 90 ° hybrid line.

  In addition, the high-frequency transmission line according to the present invention includes a termination resistor that connects a terminal that is separated from the third port by a switch circuit to the ground.

  In this configuration, there is no load fluctuation before and after switching, and the transient response at the time of switching can be improved. Thereby, the influence of the propagation loss of the high frequency signal by the terminal on the side not selected by the switch circuit can be suppressed.

  In the high frequency transmission line of the present invention, the switch circuit is composed of an electronic switch.

  In this configuration, the propagation direction (output direction) of the high-frequency signal in the waveguide can be switched at high speed.

  In the high-frequency transmission line of the present invention, the 90 ° hybrid line is formed by a microstrip line.

  In this configuration, the 90 ° hybrid line can be formed on the dielectric substrate, and the 90 ° hybrid line can be formed thin. Therefore, the high-frequency transmission line can be formed in a small size.

  In the high-frequency transmission line of the present invention, the switch circuit is formed on a substrate having a microstrip line.

  In this configuration, since the switch circuit is also formed on the dielectric substrate on which the microstrip line is formed, the high-frequency transmission line can be made smaller.

  In the high-frequency transmission line of the present invention, the third port is a high-frequency signal input terminal, and the first terminal and the second terminal are high-frequency signal output terminals.

  In this configuration, the input end and output end of a high frequency signal in a specific high frequency transmission line are defined.

  According to the present invention, a high-frequency transmission line that switches a propagation direction in a waveguide and performs mode conversion between the waveguide and another transmission line can be formed in a small size.

It is a circuit block diagram of the high frequency transmission line concerning the embodiment of the present invention. It is a figure for demonstrating the 1st operation | movement aspect of the high frequency transmission line which concerns on embodiment of this invention. It is a figure for demonstrating the 2nd operation | movement aspect of the high frequency transmission line which concerns on embodiment of this invention. 1 is an external perspective view of a high-frequency transmission line according to an embodiment of the present invention.

  A high-frequency transmission line according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit block diagram of a high-frequency transmission line according to an embodiment of the present invention.

  The high-frequency transmission line 10 includes a waveguide 20, a 90 ° hybrid line 30, a first power supply probe 41, a second power supply probe 42, and a switch circuit 50.

  The waveguide 20 is a rectangular waveguide, and one end in the propagation direction of the high-frequency signal is the first port Port21, and the other end in the propagation direction of the high-frequency signal is the second port Port22. The width and height of the opening cross section of the waveguide 20 are determined based on the frequency (wavelength λg) of the high-frequency signal propagating through the waveguide 20.

  The 90 ° hybrid line 30 includes a first terminal Ph31, a second terminal Ph32, a third terminal Ph33, and a fourth terminal Ph34, and these terminals are formed in a shape that forms square corners. The first terminal Ph31 and the second terminal Ph32 are connected with an electrical length that is approximately ¼ of the wavelength λh of the high-frequency signal propagating through the 90 ° hybrid line 30 (wavelength in the formed line). The second terminal Ph32 and the third terminal Ph33 are connected with an electrical length that is approximately ¼ of the wavelength λh of the high-frequency signal propagating through the 90 ° hybrid line 30 (the wavelength in the formed line). The third terminal Ph33 and the fourth terminal Ph34 are connected with an electrical length of approximately ¼ of the wavelength λh of the high-frequency signal propagating through the 90 ° hybrid line 30 (wavelength in the formed line). The fourth terminal Ph34 and the first terminal Ph31 are connected with an electrical length that is approximately ¼ of the wavelength λh of the high-frequency signal propagating through the 90 ° hybrid line 30 (wavelength in the formed line). Here, the electrical length of about ¼ of the wavelength λh means an electrical length in a range that can be considered to be equivalent to a phase of ¼ of the wavelength λh of the high-frequency signal in practical use.

  One end of the first power supply probe 41 is connected to the first terminal Ph31 of the 90 ° hybrid line 30, and the other end of the first power supply probe 41 is inserted into the tube of the waveguide 20.

  One end of the second power supply probe 42 is connected to the second terminal Ph32 of the 90 ° hybrid line 30, and the other end of the second power supply probe 42 is inserted into the tube of the waveguide 20.

  In the waveguide 20, the first feeding probe 41 and the second feeding probe 42 are directions in which the waveguide 20 extends (directions orthogonal to the length direction and the width direction of the waveguide 20, and propagation of high-frequency signals). Are arranged at intervals of an electrical length of about ¼ of the wavelength λg of the high-frequency signal propagating through the waveguide 20 along the direction). Here, the electrical length that is approximately ¼ of the wavelength λg means an electrical length in a range that can be regarded as equivalent to a phase that is ¼ of the wavelength λg of the high-frequency signal in practical use.

  The switch circuit 50 includes a first common terminal 511, a second common terminal 521, a first selection terminal 512, a second selection terminal 513, a third selection terminal 522, and a fourth selection terminal 523. The switch circuit 50 is an electronic switch using an FET or a diode. By making the switch circuit 50 an electronic switch, high-speed switching can be realized. For example, switching can be performed at a higher speed than a structure in which the waveguide is mechanically rotated as shown in the above-described prior art waveguide switch.

  The switch circuit 50 selectively connects the first common terminal 511 to either the first selection terminal 512 or the second selection terminal 513 by an external control signal. The switch circuit 50 selectively connects the second common terminal 521 to either the third selection terminal 522 or the fourth selection terminal 523 by a control signal from the outside.

  In the first operation mode, the switch circuit 50 connects the first common terminal 511 to the first selection terminal 512 and connects the second common terminal 521 to the fourth selection terminal 523. In the second operation mode, the switch circuit 50 connects the first common terminal 511 to the second selection terminal 513 and connects the second common terminal 521 to the third selection terminal 522.

  The first selection terminal 512 and the third selection terminal 522 of the switch circuit 50 are connected to the third port Port10. The second selection terminal 513 of the switch circuit 50 is connected to the ground via the termination resistor Ra. The fourth selection terminal 523 of the switch circuit 50 is connected to the ground via the termination resistor Rb.

  Next, the operation principle of the high-frequency transmission line 10 according to this embodiment will be described. FIG. 2 is a diagram for explaining a first operation mode of the high-frequency transmission line according to the embodiment of the present invention. FIG. 3 is a diagram for explaining a second operation mode of the high-frequency transmission line according to the embodiment of the present invention.

(First operation mode)
In the first operation mode, the switch circuit 50 connects the first common terminal 511 and the first selection terminal 512, and connects the second common terminal 521 and the fourth selection terminal 523. In this case, the high-frequency signal input from the third port Port 10 is propagated to the fourth terminal Ph 34 of the 90 ° hybrid line 30 via the first selection terminal 512 and the first common terminal 511 of the switch circuit 50.

  The high frequency signal is distributed at the fourth terminal Ph34, propagates through the 90 ° hybrid line 30, and is output to the first power supply probe 41 and the second power supply probe 42.

  The phase of the high-frequency signal (first partial high-frequency signal) fed from the first feeding probe 41 to the waveguide 20 changes by 90 ° from the fourth terminal Ph34.

  The phase of the high-frequency signal (second partial high-frequency signal) fed from the second feeding probe 42 to the waveguide 20 changes by 180 ° from the fourth terminal Ph34.

  When a high-frequency signal traveling in the direction of the second port Port 22 is taken into consideration, the phase of the first partial high-frequency signal fed by the first feeding probe 41 in the waveguide 20 is 90 when the second feeding probe 42 is reached. ° Change. Therefore, the phase of the first partial high-frequency signal changes by 180 ° before reaching the second power feeding probe 42 from the fourth terminal Ph34. Thereby, in the position of the 2nd electric power feeding probe 42, a 1st partial high frequency signal and a 2nd partial high frequency signal become the same phase, and are synthesize | combined.

  On the other hand, when a high-frequency signal traveling in the direction of the first port Port 21 is taken into consideration, the second partial high-frequency signal fed by the second feeding probe 42 in the waveguide 20 is phased when reaching the first feeding probe 41. Changes by 90 °. Therefore, the phase of the second partial high-frequency signal changes by 270 ° before reaching the first power supply probe 41 from the fourth terminal Ph34. Thereby, in the position of the 1st electric power feeding probe 41, a 1st partial high frequency signal and a 2nd partial high frequency signal become an antiphase, and are canceled.

  Therefore, in the first operation mode, the high-frequency signal input from the third port Port10 is not output to the first port Port21 and is output to the second port Port22 with little loss (with low loss).

  At this time, since the second common terminal 521 of the switch circuit 50 is connected to the fourth selection terminal 514, the third terminal Ph33 of the 90 ° hybrid line 30 is grounded via the termination resistor Rb. As a result, the third terminal Ph33 is not in an endless open state, and load fluctuations before and after switching can be eliminated. Thereby, the transient response at the time of switch switching can be improved.

(Second operation mode)
In the second operation mode, the switch circuit 50 connects the first common terminal 511 and the second selection terminal 513 and connects the second common terminal 521 and the third selection terminal 522. In this case, the high-frequency signal input from the third port Port 10 is propagated to the third terminal Ph 33 of the 90 ° hybrid line 30 via the third selection terminal 522 and the second common terminal 521 of the switch circuit 50.

  The high frequency signal is distributed at the third terminal Ph <b> 33, propagates through the 90 ° hybrid line 30, and is output to the second power supply probe 42 and the first power supply probe 41.

  The phase of the high-frequency signal (third partial high-frequency signal) fed from the second feeding probe 42 to the waveguide 20 changes by 90 ° from the third terminal Ph33.

  The phase of the high-frequency signal (fourth partial high-frequency signal) fed from the first feeding probe 41 to the waveguide 20 changes by 180 ° from the third terminal Ph33.

  When a high-frequency signal traveling in the direction of the first port Port 21 is taken into consideration, the phase of the third partial high-frequency signal fed by the second feeding probe 42 in the waveguide 20 is 90 when the first feeding probe 41 is reached. ° Change. Therefore, the phase of the third partial high-frequency signal changes by 180 ° before reaching the first power feeding probe 41 from the third terminal Ph33. Thereby, in the position of the 1st electric power feeding probe 41, a 3rd partial high frequency signal and a 4th partial high frequency signal become the same phase, and are synthesize | combined.

  On the other hand, when a high-frequency signal traveling in the direction of the second port Port 22 is taken into consideration, the fourth partial high-frequency signal fed by the first feeding probe 41 in the waveguide 20 is phased when reaching the second feeding probe 42. Changes by 90 °. Therefore, the phase of the fourth partial high-frequency signal changes by 270 ° before reaching the second power feeding probe 42 from the third terminal Ph33. Thereby, in the position of the 2nd electric power feeding probe 42, a 3rd partial high frequency signal and a 4th partial high frequency signal become an antiphase, and are canceled.

  Therefore, in the second operation mode, the high frequency signal input from the third port Port10 is not output to the second port Port22 and is output to the first port Port21 with almost no loss (with low loss).

  At this time, the first common terminal 511 of the switch circuit 50 is connected to the second selection terminal 513, so that the fourth terminal Ph34 of the 90 ° hybrid line 30 is grounded via the termination resistor Ra. As a result, the fourth terminal Ph34 is not in an endless open state, and the propagation loss of the high-frequency signal can be further suppressed.

  As described above, by using the configuration of the present embodiment, the high-frequency signal input from the third port Port10 is converted into the first port Port21 or the second port Port22 of the waveguide 20 by the switch control of the switch circuit 50. Either can be selected and output.

  Such a high-frequency transmission line 10 is realized by a structure as shown in FIG. FIG. 4 is an external perspective view of the high-frequency transmission line according to the embodiment of the present invention. In FIG. 4, only a part of the waveguide 20, the 90 ° hybrid line 30, the first power supply probe 41, and the second power supply probe 42 are illustrated.

  The waveguide 20 includes a tubular conductor 200 having a rectangular cross section. Two through holes (not shown) are formed on one H surface of the tubular conductor 200. The two through holes are formed at an interval of approximately ¼ of the wavelength λg along the extending direction of the tubular conductor 200.

  The 1st electric power feeding probe 41 and the 2nd electric power feeding probe 42 are rod-shaped conductors, and are arrange | positioned so that each may penetrate the above-mentioned through-hole.

  The 90 ° hybrid line 30 is in the form of a microstrip line and includes a dielectric substrate 300. The dielectric substrate 300 is disposed on the surface where the through hole of the tubular conductor 200 is formed. At this time, the dielectric substrate 300 is disposed such that the flat plate surface is in contact with the outer surface of the tubular conductor 200. A ground conductor 340 is formed on the entire surface of the dielectric substrate 300 on the side in contact with the tubular conductor 200.

  Microstrip lines 311, 312, 313 and 314 are formed on the surface of the dielectric substrate 300 opposite to the ground conductor 340. The microstrip lines 311 and 313 are long in the extending direction of the tubular conductor 200. The microstrip lines 312 and 314 have a long shape in a direction perpendicular to the extending direction of the microstrip lines 311 and 313. One end in the length direction of the microstrip line 311 is connected to the other end in the length direction of the microstrip line 314, and the other end in the length direction of the microstrip line 311 is connected in the length direction of the microstrip line 312. Connect to one end. The other end in the length direction of the microstrip line 312 is connected to one end in the length direction of the microstrip line 313. The other end in the length direction of the microstrip line 313 is connected to one end in the length direction of the microstrip line 314.

  The widths of the microstrip lines 311, 312, 313, and 314 are determined based on the characteristic impedance of the propagating high-frequency signal in consideration of the dielectric constant and thickness of the dielectric substrate 300. Further, the length of the microstrip lines 311, 312, 313, and 314 is set to approximately ¼ of the wavelength λh of the propagating high-frequency signal in consideration of the dielectric constant and thickness of the dielectric substrate 300.

  A connection point of the microstrip lines 311 and 314 corresponds to the first terminal Ph31 and is connected to the first power supply probe 41 via the microstrip line 321. A connection point of the microstrip lines 311 and 312 corresponds to the second terminal Ph32 and is connected to the second power supply probe 42 via the microstrip line 322. The lengths of the microstrip lines 321 and 322 are preferably the same, and it is preferable that the phases of the high-frequency signals supplied to the first power supply probe 41 and the second power supply probe 42 have a 90 ° phase difference. The lengths of the microstrip lines 321 and 322 are extremely short as compared with the microstrip lines 311, 312, 313 and 314.

  The connection point of the microstrip lines 312 and 313 corresponds to the third terminal Ph33 and is connected to the second common terminal 521 (not shown) of the switch circuit 50 via the microstrip line 332. A connection point of the microstrip lines 313 and 314 corresponds to the fourth terminal Ph34 and is connected to a first common terminal 511 (not shown) of the switch circuit 50 via the microstrip line 331. The lengths of the microstrip lines 331 and 332 are preferably the same. Furthermore, the lengths of the microstrip lines 331 and 332 are preferably extremely shorter than those of the microstrip lines 311, 312, 313, and 314, thereby further reducing the size of the high-frequency transmission line.

  With such a configuration, a thin 90 ° hybrid line 30 can be realized. Then, by attaching the thin 90 ° hybrid line 30 to the waveguide 20, the high-frequency transmission line 10 can be formed in a small size.

  Note that the switch circuit 50 and the termination resistors Ra and Rb are not shown, but may be mounted on the dielectric substrate 300. Thereby, the high frequency transmission line 10 can be further downsized.

  In the above-described embodiment, the high-frequency transmission line that also serves as the mode converter of the microstrip line and the waveguide has been described as an example. However, the high-frequency transmission line that is different from the waveguide other than the microstrip line is also described above. The configuration can be applied. However, by applying a microstrip line using a substrate having a relatively high dielectric constant, a further reduction in size and thickness can be realized.

  In the above-described embodiment, the interval between the first power supply probe 41 and the second power supply probe 42 may be an odd multiple of λg / 4, and is between the first, second, third, and fourth terminals Ph31 to Ph34. The interval may be an odd multiple of λh / 4.

  Moreover, although the example using the 90 degree hybrid line by a microstrip line was shown in the above-mentioned embodiment, the circuit which satisfy | fills the following conditions may be sufficient. First, second, third, and fourth terminals Ph31 to Ph34 are provided. The high-frequency signal input from the third terminal Ph33 is output to the first and second terminals Ph31 and Ph32, and the phase difference between these output signals is 90 °. The high frequency signal input from the fourth terminal Ph34 is output to the first and second terminals Ph31 and Ph32, and the phase difference between these output signals is 90 °. The phase relationship between the high-frequency signals input from the third terminal Ph33 and output to the first and second terminals Ph31 and Ph32 and the high-frequency signals input from the fourth terminal Ph34 and output to the first and second terminals Ph31 and Ph32 The phase relationship is reversed.

  In the above description, the case where the interval between the first power supply probe 41 and the second power supply probe 42 is limited to approximately λg / 4 is shown. However, even if the interval between the first and second power feeding probes 41 and 42 is different from about λg / 4, by adjusting the interval between the first, second, third, and fourth terminals Ph31 to Ph34, It is possible to obtain the same effect.

10: High-frequency transmission line,
20: Waveguide,
30: 90 ° hybrid line,
41: 1st electric power feeding probe,
42: second power supply probe,
50: switch circuit,
200: tubular conductor,
300: dielectric substrate,
311, 312, 313, 314, 321, 322, 331, 332: microstrip line,
340: ground conductor,
Port 21: First port
Port 22: second port,
Port 10: third port,
Ra, Rb: Terminating resistance

Claims (7)

A waveguide having a first port and a second port, capable of propagating high-frequency signals between these ports;
A first terminal, a second terminal, a third terminal, and a fourth terminal are provided, and a high-frequency signal input from the third terminal or the fourth terminal is distributed to the first terminal and the second terminal and is about 90 °. A 90 ° hybrid line that is output with a phase difference and in which the phase relationship between the high-frequency signal output when the high-frequency signal is input from the third terminal and the high-frequency signal input from the fourth terminal is reversed;
A first feeding probe having one end connected to the first terminal and the other end inserted into the waveguide, and one end connected to the second terminal and the other end inserted into the waveguide. A second power supply probe disposed between the power supply probe and an odd multiple of 1/4 of the in-tube wavelength of the high-frequency signal;
A switch circuit that selectively connects the third terminal and the fourth terminal to a third port;
High-frequency transmission line with The high-frequency transmission line according to claim 1,
The 90 ° hybrid line has a structure in which a first terminal, a second terminal, a third terminal, and a fourth terminal are connected by electric lines each having an odd multiple of 1/4 with respect to the wavelength of the high-frequency signal. A high-frequency transmission line consisting of The high-frequency transmission line according to claim 1 or 2,
A high-frequency transmission line comprising a termination resistor that connects a terminal that is separated from the third port by the switch circuit to a ground. The high-frequency transmission line according to any one of claims 1 to 3,
The switch circuit is a high-frequency transmission line including an electronic switch. The high-frequency transmission line according to any one of claims 1 to 4,
The 90 ° hybrid line is a high-frequency transmission line formed by a microstrip line. The high-frequency transmission line according to claim 5,
The switch circuit is a high-frequency transmission line formed on a substrate including the microstrip line. The high-frequency transmission line according to any one of claims 1 to 6,
A high-frequency transmission line, wherein the third port is a high-frequency signal input terminal, and the first terminal and the second terminal are high-frequency signal output terminals.

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