JP4277766B2 - Mechanical reflection type phase shifter - Google Patents

Description

  The present invention relates to a mechanical reflection type phase shifter that mechanically moves a reflector, and relates to a mechanical reflection type phase shifter that improves reflection efficiency while reducing the size.

  A mechanical reflection type phase shifter is often used as a phase shifter used for beam control or phase modulation of a phased array antenna. As shown in FIG. 9, in the conventional mechanical reflection type phase shifter, a quarter-wave reflector 92 is placed on a line 91 such as a microstrip line so that the impedance changes abruptly.

  The phase of the reflected wave of the signal is changed by moving the reflecting plate 92 along the line 91. When the amount of phase shift is 45 degrees or more, a hybrid circuit is combined with this configuration. Further, in order to increase the reflection efficiency, a plurality of reflection plates 92 are arranged at quarter wavelength intervals in the longitudinal direction of the line. The greater the difference in impedance due to the reflector 92, the higher the reflection efficiency.

  In addition, when the reflector 92 has a single stage, even if it is provided in multiple stages, a signal that cannot be reflected by the reflector 92 reaches the end of the line 91 (not shown), and this signal is reflected at the end. The signal reflected by the reflector 92 and the phase do not match. Therefore, conventionally, a terminator is provided at a terminal (not shown) of the line 91, and this terminator converts an excess signal into heat and absorbs it.

JP 2003-318602 A

  In the mechanical reflection type phase shifter described above, it is preferable to increase the difference in impedance in order to improve the reflectivity. For this purpose, the width of the reflector (the side perpendicular to the longitudinal direction of the line) must be increased. is required. It is also effective to arrange a plurality of reflectors to be a multistage type.

  However, when the width of the reflecting plate is increased, the shape of the reflecting plate is rectangular, and the phase shifter is accordingly increased. In addition, when the multistage type is used, the line is extended in the longitudinal direction, so that the phase shifter is also enlarged.

  For these reasons, it has been difficult to improve the reflection efficiency while reducing the size of the phase shifter.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mechanical reflection type phase shifter that solves the above problems and improves the reflection efficiency while reducing the size.

According to a first aspect of the present invention, one of the terminals of the 90-degree hybrid circuit is used as an input terminal, and microstrip lines extending in a straight line are connected to two adjacent terminals of the 90-degree hybrid circuit, respectively. An open strip line that extends beyond the microstrip line and ends at an open end is provided in the middle of the line so as to be mechanically movable along the microstrip line and to transmit signals to the microstrip line. a was械式reflection phase shifter, the beginning of the release strip line, while being thicker than the end of the release strip line, Ri between the terminal end and the starting end, a narrower impedance There is formed a step ing the mismatch, the reflection wave from the terminating and the reflected wave from the step is made in phase.

In the second invention, one terminal of each of the two 90-degree hybrid circuits is connected to the output terminal of the distributor that divides the signal from the input terminal into two, and the two adjacent 90-degree hybrid circuits are connected to the two terminals adjacent to each other. Each of the microstrip lines extending in a straight line is connected, and a release strip line that extends beyond the microstrip line and ends at an open end is machined along the microstrip line in the middle of each microstrip line. A mechanical reflection type phase shifter provided so as to be movable and capable of transmitting a signal to the microstrip line, wherein the start end of the release strip line is formed thicker than the end of the release strip line , between the end and the beginning, a step is formed impedance Ri of narrow width ing mismatched Reflected wave from the end and the reflected wave from the step is made in phase.

A distributor that divides the signal from the remaining terminal into two is connected to the remaining terminal of the 90-degree hybrid circuit, and the 90-degree of the next stage is connected to the output terminal of the distributor that distributes the signal from the remaining terminal into two. One terminal of the hybrid circuit may be connected, and a microstrip line and a release strip line similar to the above may be provided to be multistaged.

  The open strip line may be galvanically insulated from the microstrip line and be capable of transmitting signals in an alternating manner.

  The present invention exhibits the following excellent effects.

  (1) Since the termination of the open strip line is the open end, the reflection efficiency is good.

  (2) Since the width of the open strip line may be the same as that of the microstrip line, the phase shifter can be miniaturized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the phase shifter according to the first aspect of the present invention has a microstrip line 2 that extends linearly from the input end 1, and extends beyond the microstrip line 2 to have a termination 3. An open strip line 4 as an open end is provided so as to be mechanically movable along the microstrip line 2 and capable of transmitting signals to the microstrip line 2.

  In this phase shifter, the conventional phase shifter has a reflector made up of a reflector, whereas the reflector is made up of an open strip line 4.

  In the illustrated example, the release strip line 4 is formed slightly narrower than the microstrip line 2. The open strip line 4 partially overlaps the micro strip line 2, the starting end 5 of the open strip line 4 is in the middle of the micro strip line 2, and the end 3 of the open strip line 4 is the micro strip line 2. It extends before the end 6 of.

  The movement range of the release strip line 4 is a range in which the start end 5 of the release strip line 4 overlaps the microstrip line 2 and the end 3 of the release strip line 4 is located before the end 6 of the microstrip line 2.

  The release strip line 4 partially overlaps the microstrip line 2, so that the release strip line 4 can transmit signals to the microstrip line 2. There are two modes in which the release strip line 4 overlaps the microstrip line 2.

  That is, in the configuration of FIG. 2, the release strip line 4 is in direct contact with and overlaps the microstrip line 2. The open strip line 4 is electrically connected to the microstrip line 2, in other words, connected in a direct current manner.

  Since the open strip line 4 is substantially the same in thickness and width as the micro strip line 2, there is no impedance mismatch at the starting end 5 of the open strip line 4, and the current flowing from the input end 1 to the micro strip line 2 is attenuated. And flows into the open stripline 4 without reflection. However, the open strip line 4 has the open end 3 at the end 3. This open end is equivalent to an infinite impedance connected to a line having a finite impedance. Due to this impedance mismatch, the current is reflected at the termination 3. The reflected current returns back to the microstrip line 2.

  In the configuration of FIG. 3, the release strip line 4 is insulated from the microstrip line 2 by air or an insulator. Since the gap is appropriately narrow, the open strip line 4 is insulated from the microstrip line 2 in terms of direct current, but is coupled in terms of alternating current to enable signal transmission. Specifically, as shown in FIG. 4, a current flows through the microstrip line 2 to form a magnetic field H, and induced in the magnetic field H, a reverse current flows through the release strip line 4. Also in this case, since the open strip line 4 has the terminal 3 at the open end, the current is reflected at the terminal 3. Therefore, the configuration of FIG. 2 and the configuration of FIG. 3 are equivalent.

  As described above, in the first invention, reflection is caused by an infinite impedance difference at the terminal end 3 of the open strip line 4. Therefore, the reflection efficiency is improved. Moreover, it is not necessary to increase the width of the reflecting plate in order to increase the reflection efficiency as in the conventional method using the reflecting plate. As a result, the phase shifter can be reduced in size. Needless to say, no terminator is required at the end 3 of the open strip line 4 or the end 6 of the microstrip line 2.

  Since the end 6 of the microstrip line 2 is located on the start end 5 side of the end 3 of the open strip line 4, all signals propagated through the microstrip line 2 are not reflected by the end 6, and are all released from the open strip line 4. Flow into. That is, it can be said that the end 3 of the open strip line 4 is equivalently the end of the microstrip line 2. Therefore, moving the release stripline 4 is equivalent to moving the end of the microstripline 2.

  Here, the materials of the microstrip line 2 and the release strip line 4 will be described. As shown in FIGS. 2 to 4, a ground conductor 8 is provided on the back surface of the substrate 7 made of an insulator, and the surface of the substrate 7 is formed. Are provided with a microstrip line 2 and an open strip line 4. The release strip line 4 may be made of a metal plate or may be made of a metal foil formed on a printed board.

  A modification of the first invention is shown in FIGS.

  The open strip line superimposed on the microstrip line 2 only needs to have an open end, and does not depend on the width or length. The open strip line 51 shown in FIG. 5 is wider than the microstrip line 2 to be coupled. The release strip line 51 extends ahead of the end 6 of the microstrip line 2 and the end 52 is released. Also in this embodiment, since the end 52 of the open strip line 51 is an open end, the reflection efficiency can be improved in the same manner as in the embodiment of FIG.

  Further, in the open strip line 61 shown in FIG. 6, the start end 62 of the open strip line 4 is significantly thicker than the end 63, and a step 64 whose width is abruptly narrowed is formed between the start end 62 and the end 63. It is.

  Since the impedance is mismatched at this level difference 64, transmission signal reflection occurs. The distance from the start end 62 to the step and the distance from the start end 62 to the end 63 are determined so that the reflected wave from the step 64 and the reflected wave from the end 63 are in phase. Thereby, the reflection efficiency is further improved.

  5 and 6, the release strip lines 51 and 61 can be mechanically moved along the microstrip line 2 like the release strip line 4 in FIG. 1. The mechanism for moving these release strip lines 4, 51, 61 may be the same as the mechanism for moving a conventional reflector, and is configured by appropriately combining an actuator such as a motor and a power transmission means such as a shaft or gear. .

  The phase shifter according to the second invention is a combination of a 90-degree hybrid circuit with the phase shifter according to the first invention. That is, as shown in FIG. 7, the phase shifter has one terminal (terminal A) of the 90-degree hybrid circuit 71 as an input end, and two adjacent terminals B, 90, 90 of the 90-degree hybrid circuit 71. Microstrip lines 72, 72 extending in a straight line are connected to C, and an open strip line 73 that extends along the microstrip line 72 and ends at an open end is connected to the microstrip line 72. It is provided so as to be mechanically movable along the strip line 72 and capable of transmitting signals to the microstrip line 72.

  The details of the microstrip line 72 and the open strip line 73 are as described in the first invention.

  On the other hand, the 90-degree hybrid circuit 71 is configured by assembling four 90-degree delay elements 74 in a grid pattern and using the connection points formed at the four corners as terminals. Called terminals A, B, C, and D clockwise. The signal at terminal A appears at terminal B with a phase delay of 90 degrees. The signal at terminal B appears at terminal C with a phase delay of 90 degrees. The signal at terminal C appears at terminal D with a phase delay of 90 degrees. Thus, the phase is delayed by 90 degrees by passing through the 90-degree delay element 74 once. When passing through the 90-degree delay element 74 twice or more, a delay corresponding to the number of times is added.

  Now, when a high-frequency signal having a frequency at the terminal A of the 90-degree hybrid circuit 71 that is the input terminal is input, the signal is output to the terminal B and the terminal C by dividing the power by 1/2. With reference to terminal A, the phase at terminal B is 90 degrees and the phase at terminal C is 180 degrees. The signal output from the terminal B flows from the microstrip line 72 to the release strip line 73, is totally reflected at the open end of the release strip line 73, and returns to the terminal B. Although the phase of the signal returning to the terminal B can be changed by moving the release strip line 73, here, for simplicity, the phase is the same, that is, the phase is 90 degrees with the terminal A reference (hereinafter the same). Suppose that

  Similarly, the signal output from the terminal C flows from the microstrip line 72 to the release strip line 73, is totally reflected at the open end of the release strip line 73, and returns to the terminal B. This is also the same phase, that is, a phase of 180 degrees.

  When a signal returning to terminal B appears at terminal A, the phase of the signal is 180 degrees. When a signal returning to terminal C appears at terminal A, the phase of the signal is 360 degrees. That is, at the terminal A, both return signals have opposite phases. Both return signals are canceled because they have the same power.

  On the other hand, when the signal returned to the terminal B appears at the terminal D, the phase of the signal is 270 degrees. When the signal returned to terminal C appears at terminal D, the phase of the signal is 270 degrees. That is, at the terminal D, both return signals have the same phase.

  As a result, when a signal is input from the outside to the terminal A, a signal reflected at the open end of the open strip line 73 on the terminal B side and a signal reflected at the open end of the open strip line 73 on the terminal C side are obtained. It is synthesized and output from the terminal D to the outside.

  Next, considering that the release strip line 73 is moved along the microstrip line 72, the relationship between the phase delay at the terminal D with respect to the signal at the terminal B and the phase delay at the terminal D with respect to the signal at the terminal C is fixed. Therefore, if the movement amount of the release strip line 73 on the terminal B side and the movement amount of the release strip line 73 on the terminal C side are the same, the relationship in which both return signals are in phase with each other at the terminal D is maintained. That is, when the two open strip lines 73 are moved by the same distance along the microstrip line 72, the phase of the signal reflected at the open end changes, and the phase of the output from the terminal D changes.

  As a mechanism for moving the two release strip lines 73 along the microstrip line 72, respectively, for example, two microstrip lines 72 parallel to each other are printed on one substrate, Two open strip lines 73 that are parallel to each other at the same pitch are printed on the substrate, and the two substrates are overlapped so that one substrate can move along the other substrate. The release stripline 73 is allowed to move.

  The phase shifter according to the third invention is a combination of a plurality of phase shifters according to the second invention. That is, as shown in FIG. 8, the phase shifter has one terminal of each of the two 90-degree hybrid circuits 84 and 84 at the output terminals 83 and 83 of the distributor 82 that divides the signal from the input terminal 81 into two. A and A are connected, and for each 90-degree hybrid circuit 84, microstrip lines 85 and 85 extending in a straight line are connected to two terminals B and C adjacent to each other, and in the middle of each microstrip line 85, respectively. An open strip line 87 extending along the microstrip line 85 and having a terminal end 86 as an open end is provided so as to be mechanically movable along the microstrip line 85 and to transmit signals to the microstrip line 85. Is.

  The combination of one 90-degree hybrid circuit 84 and two microstrip lines 85 and an open strip line 87 is as already described in the second invention. The two signals distributed by the distributor 82 are input to the two 90 degree hybrid circuits 84 and 84 as described above. Therefore, the signals reflected by the open ends of the two open strip lines 87 appear in phase at the terminals D of each 90-degree hybrid circuit 84, and the combined signal is output from the terminal D.

  The movement amount of the two open strip lines 87 in the left half of the figure and the movement amount of the two open strip lines 87 in the right half match or do not match, thereby being output from the terminal D of the left 90-degree hybrid circuit 84. The signal and the signal output from the terminal D of the right 90-degree hybrid circuit 84 can be output in the same phase or in different phases.

  In the phase shifter of FIG. 8, a distributor 88 that distributes the signal from the terminal D to the terminal D of the 90-degree hybrid circuit 84 is further connected to one of the output terminals 89 of the next stage. One terminal A of the 90-degree hybrid circuit 84 ′ is connected, and a microstrip line 85 ′ and a release strip line 87 ′ similar to those described above are provided. That is, the phase shifter according to the third invention can be configured in two stages. Furthermore, by repeating the connection of the same configuration to the terminal D of the 90-degree hybrid circuit 84 ', the number of stages can be increased to an arbitrary number.

  If a load is connected to the other output terminal of the distributor 88, a large number of loads can be connected in the case of multiple stages. Therefore, in a multi-element antenna such as an array antenna, if each element is connected to the phase shifter of FIG. 8 as a load, the phase of the signal output to each element can be individually controlled.

It is a top view of the phase shifter which shows one Embodiment of this invention. FIG. 2 is a side sectional view according to an embodiment of the phase shifter of FIG. 1. FIG. 6 is a side sectional view according to another embodiment of the phase shifter of FIG. 1. It is the cross-sectional view which looked at the phase shifter of FIG. 3 from the input end. It is a top view of the phase shifter which shows other embodiment of this invention. It is a top view of the phase shifter which shows other embodiment of this invention. It is a conceptual diagram of the phase shifter which shows one Embodiment of this invention. It is a conceptual diagram of the phase shifter which shows one Embodiment of this invention. It is a top view of the conventional phase shifter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,81 Input end 2,72,85 Microstrip line 3 Termination of release strip line 4,51,61,73,87 Release strip line 82 Divider

Claims (4)

One of the terminals of the 90-degree hybrid circuit is used as an input terminal, and microstrip lines extending in a straight line are connected to two terminals adjacent to each other of the 90-degree hybrid circuit. A mechanical reflection-type transfer that is provided so that an open strip line extending beyond the microstrip line and having an open end is movable along the microstrip line and capable of transmitting signals to the microstrip line. A phaser,
The beginning of the release strip line, while being thicker than the end of the release strip line, between the end and the beginning, is formed stepped impedance Ri of narrow width ing inconsistent, the A mechanical reflection type phase shifter, wherein a reflected wave from a step and a reflected wave from the terminal end are in phase. One terminal of each of the two 90 degree hybrid circuits is connected to the output terminal of the distributor that divides the signal from the input terminal into two, and each 90 degree hybrid circuit extends linearly to two terminals adjacent to each other. A microstrip line is connected, and in the middle of each microstrip line, an open strip line extending beyond the microstrip line and having a termination end is mechanically movable along the microstrip line and A mechanical reflection type phase shifter provided so as to be able to transmit a signal to a microstrip line,
The beginning of the release strip line, while being thicker than the end of the release strip line, between the end and the beginning, is formed stepped impedance Ri of narrow width ing inconsistent, the A mechanical reflection type phase shifter, wherein a reflected wave from a step and a reflected wave from the terminal end are in phase.   A distributor that divides the signal from the remaining terminal into two is connected to the remaining terminal of the 90-degree hybrid circuit, and the 90-degree of the next stage is connected to the output terminal of the distributor that divides the signal from the remaining terminal into two. 3. The mechanical reflection type phase shifter according to claim 2, wherein one terminal of the hybrid circuit is connected, and a microstrip line and a release strip line similar to the above are provided to be multistaged.   The mechanical reflective phase shifter according to any one of claims 1 to 3, wherein the open strip line is galvanically insulated from the microstrip line and is capable of transmitting signals in an alternating manner.

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