Waveguide switch
09793588 · 2017-10-17
Assignee
Inventors
Cpc classification
International classification
Abstract
A movable waveguide block 50 having transmission lines 51 and 52 slides in a non-contact manner between a first end surface 30b of a first fixing waveguide block 30 having transmission lines 31 and 32 and a second end surface 40a of a second fixing waveguide block 40 having a transmission line 41, and switching of propagation paths is performed. Grooves 35A, 35B, 36A, 36B, 45A, 45B, 55A, 55B, 56A, 56B, 57A, 57B, 58A, and 58B having depths equivalent to ¼ of a guide wavelength of an electromagnetic wave of a leakage prevention object are provided in pairs around openings of the transmission lines 31, 32, 41, 51, and 52 facing each other across a gap between blocks. Accordingly, unintended leakage of electromagnetic waves to the transmission lines via the gap between the blocks is prevented, and isolation increases.
Claims
1. A waveguide switch, comprising: a base portion; a first fixing waveguide block which is fixed to the base portion and in which a plurality of transmission lines surrounded by metal walls is formed to penetrate to a first end surface; a second fixing waveguide block which is fixed to the base portion and has a second end surface parallel to the first end surface of the first fixing waveguide block, and in which a transmission line surrounded by metal walls is formed to penetrate from the second end surface; and a movable waveguide block which includes a third end surface which is parallel to and faces the first end surface of the first fixing waveguide block at a predetermined interval from the first end surface, a fourth end surface which is parallel to and faces the second end surface of the second fixing waveguide block at a predetermined interval from the second end surface, and a plurality of transmission lines surrounded by metal walls which are formed to penetrate from the third end surface to the fourth end surface, and which is supported by the base portion in a state where the movable waveguide block can slide in parallel to the first end surface of the first fixing waveguide block and the second end surface of the second fixing waveguide block due to a drive device, wherein grooves having a depth equivalent to ¼ of a guide wavelength of a leakage prevention object frequency are provided to prevent leakage of electromagnetic waves from a gap between the blocks at a position of a portion which surrounds each of openings of the plurality of transmission lines of the first fixing waveguide block on the first end surface side of the first fixing waveguide block, a position of a portion which surrounds an opening of the waveguide of the second fixing waveguide block on the second end surface side of the second fixing waveguide block, and a position of a portion which surrounds each of openings of the plurality of waveguides of the movable waveguide block on the third end surface side and the fourth end surface side of the movable waveguide block.
2. The waveguide switch according to claim 1, wherein the plurality of transmission lines of the first fixing waveguide block are formed to penetrate from a fifth end surface facing the first end surface toward the first end surface, wherein the transmission line of the second fixing waveguide block is formed to penetrate from the second end surface toward a sixth end surface facing the second end surface, wherein the drive device is provided in the base portion, and wherein the movable waveguide block is formed such that some of the plurality of transmission lines of the movable waveguide block connect some of the plurality of transmission lines of the first fixing waveguide block and the transmission line of the second fixing waveguide block when the movable waveguide block is positioned at a first position, and some other portions of the transmission lines of the movable waveguide block connect some other portions of the plurality of transmission lines of the first fixing waveguide block and the transmission line of the second fixing waveguide block when the movable waveguide block is positioned at a second position.
3. The waveguide switch according to claim 1, wherein the plurality of grooves are concentrically provided at predetermined intervals.
4. The waveguide switch according to claim 2, wherein the plurality of grooves are concentrically provided at predetermined intervals.
5. The waveguide switch according to claim 3, wherein a distance between the openings of the transmission lines of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block and an inner groove is ¼ of a guide wavelength of a frequency in a region sufficiently lower than a lower limit of a transmission frequency region of the transmission line.
6. The waveguide switch according to claim 4, wherein a distance between the openings of the transmission lines of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block and an inner groove is ¼ of a guide wavelength of a frequency in a region sufficiently lower than a lower limit of a transmission frequency region of the transmission line.
7. The waveguide switch according to claim 3, wherein a distance between an inner groove and an outer groove of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block is ¼ of a guide wavelength of an odd number multiple of a transmission center frequency of the transmission line.
8. The waveguide switch according to claim 4, wherein a distance between an inner groove and an outer groove of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block is ¼ of a guide wavelength of an odd number multiple of a transmission center frequency of the transmission line.
9. The waveguide switch according to claim 5, wherein a distance between an inner groove and an outer groove of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block is ¼ of a guide wavelength of an odd number multiple of a transmission center frequency of the transmission line.
10. The waveguide switch according to claim 6, wherein a distance between an inner groove and an outer groove of each of the first end surface side of the first fixing waveguide block, the second end surface side of the second fixing waveguide block, and the third end surface side and the fourth end surface side of the movable waveguide block is ¼ of a guide wavelength of an odd number multiple of a transmission center frequency of the transmission line.
11. The waveguide switch according to claim 1, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
12. The waveguide switch according to claim 2, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
13. The waveguide switch according to claim 3, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
14. The waveguide switch according to claim 4, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
15. The waveguide switch according to claim 5, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
16. The waveguide switch according to claim 6, wherein an upper surface, a side surface, and a lower surface of the waveguide switch are covered with a metal case, and an upper surface and a side surface of the movable waveguide block are not in contact with an inner wall of the metal case.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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BEST MODE FOR CARRYING OUT THE INVENTION
(22) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
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(24) As shown in the drawings, the waveguide switch 20 includes a base portion 21, a first fixing waveguide block 30, a second fixing waveguide block 40, and a movable waveguide block 50.
(25) An outline of the base portion 21 is formed in a rectangular shape, the first fixing waveguide block 30 is fixed to one end side of an upper surface 21a of the base portion 21, and the second fixing waveguide block 40 is fixed to the other end side of the upper surface 21a.
(26) The first fixing waveguide block 30 is formed in a rectangular parallelepiped shape, and is formed so that a plurality of (two in this example) transmission lines 31 and 32 which are surrounded by metal walls and have predetermined sectional sizes penetrate from a fifth end surface 30a to a first end surface 30b opposite to the fifth end surface 30a. Here, for example, each of the two transmission lines 31 and 32 has a sectional size (for example, approximately 2 mm×1 mm) capable of propagating electromagnetic waves of a millimeter wave band in a single mode (TE10 mode), and the two transmission lines 31 and 32 are formed so as to be parallel to each other with a predetermined interval therebetween in a direction orthogonal to the fifth end surface 30a and the first end surface 30b at the same height as each other from the upper surface 21a of the base portion 21.
(27) Meanwhile, an outline of the second fixing waveguide block 40 is formed in the same rectangular parallelepiped shape as the outline of the first fixing waveguide block 30, the second fixing waveguide block 40 is fixed to the base portion 21 in a state where a second end surface 40a of the second fixing waveguide block 40 is parallel to and faces the first end surface 30b of the first fixing waveguide block 30 at a predetermined distance therefrom, and a transmission line 41 surrounded by metal walls is formed to penetrate from the second end surface 40a to a sixth end surface 40b opposite to the second end surface 40a. The sectional size and the height of the transmission line 41 are the same as those of the transmission lines 31 and 32 of the first fixing waveguide block 30, and the transmission line 41 is formed on a line passing through an intermediate portion of the transmission lines 31 and 32.
(28) In addition, this embodiment shows the structure example in which the first end surface 30b of the first fixing waveguide block 30 and the second end surface 40a of the second fixing waveguide block 40 are parallel to and face each other in the state of being separated from each other by a predetermined distance. However, as described below, a structure example may be realized in which the first end surface 30b of the first fixing waveguide block 30 and the second end surface 40a of the second fixing waveguide block 40 face in the same direction so as to be flush with each other.
(29) The movable waveguide block 50 is slidably supported between the first end surface 30b of the first fixing waveguide block 30 and the second end surface 40a of the second fixing waveguide block 40 on the upper surface 21a of the base portion 21. The movable waveguide block 50 is formed in a rectangular parallelepiped shape which has a slightly (for example, 60 μm) shorter length than the distance between the first end surface 30b of the first fixing waveguide block 30 and the second end surface 40a of the second fixing waveguide block 40 and approximately the same height as the height of each of both fixing waveguide blocks 30 and 40, and two transmission lines 51 and 52 corresponding to the number of transmission lines 31 and 32 formed in the first fixing waveguide block 30 are formed so as to penetrate from a third end surface 50a which is parallel to and faces the first end surface 30b of the first fixing waveguide block 30 with a gap g (for example, g=30 μm) between it and the first end surface 30b to a fourth end surface 50b which is parallel to and faces the second end surface 40a of the second fixing waveguide block 40 with the gap g between it and the second end surface 40a.
(30) The sectional size and the height of each of the transmission lines 51 and 52 of the movable waveguide block 50 are the same as those of each of the transmission lines 31 and 32 of the first fixing waveguide block 30 and those of the transmission line 41 of the second fixing waveguide block 40, and in a position (hereinafter, referred to as a neutral state) shown in
(31) Accordingly, as shown in
(32) In addition, in a second position at which the movable waveguide block 50 slides by 2 L in the width direction (Y direction) from the state of
(33) In addition, this example is configured so that the transmission line 41 of the second fixing waveguide block 40 is positioned on an extension line passing through the intermediate portion of the two transmission lines 31 and of the first fixing waveguide block 30 and the two transmission lines 51 and 52 of the movable waveguide block 50 are linearly symmetrical with respect to the extension line. However, an unsymmetrical structure may be adopted in which the transmission line 41 of the second fixing waveguide block 40 is not positioned on an extension line of a line passing through the intermediate portion of the two transmission lines 31 and 32 of the first fixing waveguide block 30, and in this case, the two transmission lines 51 and 52 of the movable waveguide block 50 are unsymmetrically disposed.
(34) The movable waveguide block 50 is slidably supported by a drive device 60 which is provided in the base portion 21. The structure of the drive device 60 is arbitrarily adopted. For example, the structure may be realized by inverting a rotational movement of a stepping motor into a linear movement and transmitting the linear movement to a support member which supports the movable waveguide block 50 from a lower surface side of the base portion 21. In this case, a position and a movement distance of the movable waveguide block 50 are detected by a sensor, an encoder, or the like, and the movable waveguide block 50 may be controlled so as to be selectively movable between at least the first position of
(35) In the waveguide switch 20 of the embodiment, since the movable waveguide block 50 slides with respect to the first fixing waveguide block 30 and the second fixing waveguide block 40 and switching of propagation paths is performed, even when the number of times of switching in the propagation paths increases, it is possible to cope with the increase of the number of times of switching by simply increasing the number of the transmission lines in the slide direction (Y direction) of the movable waveguide block 50, that is, by increasing a size only in one direction. Accordingly, it is possible to decrease the size of the waveguide switch, and since the input port and the output port does not approach each other, there is less possibility of isolation deteriorating.
(36) However, since the gap g between each of both fixing waveguide blocks 30 and 40 and the movable waveguide block needs to exist, leakage of electromagnetic waves through the gap g occurs. Particularly, when the electromagnetic waves have short wavelengths such as a millimeter wave band, considerable leakage occurs even in the slight gap of approximately 30 μm as described above, and for example, in the state of
(37) In order to solve this problem, in the waveguide switch 20 of the embodiment, as shown in
(38) Each of the grooves 35A, 35B, 36A and 36B has a function which combines electromagnetic waves which are leaked from each opening of the transmission lines 31 and 32 to the gap between the blocks and reach the inlet of the groove, and electromagnetic waves which reciprocate in the groove, return to the inlet, and have inverted phases so as to cancel each other out. Accordingly, according to this function, it is possible to prevent the electromagnetic waves from being leaked outside the groove. In addition, here, two grooves are concentrically provided in each transmission line so as to increase leakage prevention effects. However, one groove may be provided. Moreover, conversely, when three grooves or four grooves are concentrically provided, it is possible to further increase leakage prevention effects. In addition, when the plurality of grooves are concentrically provided in each transmission line, if a depth of each groove is slightly changed, it is possible to prevent leakage of the electromagnetic waves over a wide frequency band.
(39) Moreover, as shown in
(40) In addition, as shown in
(41) Moreover, here, all distances from the openings of the transmission lines to the inner grooves 35A, 36A, 45A, 55A, 56A, 57A, and 58A are the same as one another, and distances from the inner grooves 35A, 36A, 45A, 55A, 56A, 57A, and 58A to the outer grooves 35B, 36B, 45B, 55B, 56B, 57B, and 58B are the same as each other.
(42) In a numerical example, when a transmission center frequency of a transmission line is 115 GHz, the depth of each groove is (300×10.sup.6/115×10.sup.9)/4=0.65 mm.
(43) In addition, the distance from the opening of each transmission line to the inner groove is set to ¼ (for example, 1 mm) of the guide wavelength of a frequency (for example, 75 GHz) in a region sufficiently lower than a lower limit of a transmission frequency region (for example, 90 GHz to 140 GHz) of the transmission line, and reflection generated due to the section from the opening of the transmission line to the inner groove functioning as a band rejection filter is not generated within the transmission frequency region.
(44) Moreover, the distance from the inner groove to the outer groove is set to an odd number multiple of ¼ (for example, 0.65 mm) of a guide wavelength of a transmission center frequency (for example, 115 GHz), the portion between the inner groove and the outer groove functions as the band rejection filter, and leakage prevention effects of electromagnetic waves increase.
(45) In this way, in the waveguide switch 20 of the embodiment, since grooves for preventing leakage of electromagnetic waves are provided on the end surfaces facing each other with the gap between the blocks at positions surrounding the openings of the transmission lines, even when the gap is provided between the blocks, it is possible to prevent leakage of the electromagnetic waves and deterioration of isolation. In addition, unlike a contact type waveguide switch, a decrease in durability due to abrasion does not occur, and it is possible to obtain high durability.
(46) Moreover, the upper surface, the side surfaces, and the lower surface of the waveguide switch 20 are covered with a metal case (not shown), and the upper surface and the side surfaces of the movable waveguide block 50 are in a non-contact state with the inner walls of the metal case.
(47) Next, simulation results with respect to transmission characteristics of the waveguide switch 20 having the above-described configuration will be described. Conditions of simulation are as follows. The sectional section of each of the transmission lines 31, 32, 41, 51, and 52 is 2.032 mm×1.016 mm, the interval (a distance between side surfaces closer to each other) between the transmission lines 31 and 32 is 5 mm, the gap g between the blocks is 30 μm, the length (a length in the Z direction) of the movable waveguide block 50 is 10.0 mm, the width of each groove for preventing leakage of electromagnetic waves is 0.2 mm, the depth of each groove is 0.7 mm, the distance from the inner wall of each transmission line to the inner groove is 0.95 mm, and the distance between the inner groove and the outer groove is 0.65 mm.
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(49) As it is clear from
(50) Next, results of changes of characteristics with respect to position deviation of the movable waveguide block 50 will be described.
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(52) As it is clear from the results, even when the position of the movable waveguide block 50 (the position of the transmission line 51) is deviated by approximately 0.1 mm in the width direction or the height direction with respect to the normal position, the isolation slightly deteriorates (approximately 70 dB), and there is little loss or deterioration in the characteristics of the reflection. In an actual drive control, it is considered that accuracy of several μm is obtained even when the control is performed by a simple motor drive which does not have an encoder. Accordingly, it is possible to accurately perform switching of propagation paths of a millimeter wave band by a simple and inexpensive mechanism.
(53) The above-described embodiment is a configuration example of a one-circuit and two-contact point type waveguide switch. However, in order to obtain a large number of times of switching, the number of transmission lines of the first fixing waveguide block 30 may be set to 3 or more, and according to this, the number of transmission lines of the movable waveguide block 50 may increase.
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(55) In this case, as shown in
(56) In this reference position, the transmission line 32 and the transmission line 41 are connected to each other via the transmission line 52. Moreover, as shown in
(57) In the example, the number of contact points increases. However, as shown in
(58) Moreover, although it is not shown in the drawings, if there are set to be three pairs of the transmission lines of each of the first fixing waveguide block 30 and the movable waveguide block 50 of the waveguide switch shown in
(59) In addition, in this embodiment, the first end surface 30b of the first fixing waveguide block 30 and the second end surface 40a of the second fixing waveguide block 40 face each other so as to be parallel to each other with a predetermined distance therebetween, and the movable waveguide block 50 is disposed therebetween. However, as shown in
(60) Moreover, in this structure example, when the movable waveguide block 50 is positioned at the position of
(61) Although it is not shown in the drawings, the structure example shown in
(62) In addition, in each embodiment, outlines of the fixing waveguide blocks 30 and 40 and the movable waveguide block 50 are formed in rectangular parallelepiped shapes. However, the outline of each waveguide block may be arbitrarily adopted and is not limited to the rectangular parallelepiped shape. In addition, two end surfaces formed on the openings of both ends of each transmission line are not limited to surfaces opposite to each other. That is, two end surfaces may be side surfaces adjacent to each other or may be combinations of the side surfaces and the upper surface. Moreover, the base portion 21 and the fixing waveguide blocks 30 and 40 may be formed so as to be integrated with each other.
(63) In addition, even when reference numerals are omitted in each embodiment shown in
DESCRIPTION OF REFERENCE NUMERALS AND SIGNS
(64) 20 . . . waveguide switch, 21 . . . base portion, 30 . . . first fixing waveguide block, 30a and 30b . . . end surface, 31 to 33, 31A, 31B, 32A, and 32B . . . transmission line, 35A, 35B, 36A, and 36B . . . groove, 40 . . . second fixing waveguide block, 40a and 40b . . . end surface, 41, 41A, and 41B . . . transmission line, 45A and 45B . . . groove, 50 . . . movable waveguide block, 50a and 50b . . . end surface, 51 to 53, 51A, 51B, 52A, and 52B . . . transmission line, 55A, 55B, 56A, 56B, 57A, 57B, 58A, and 58B . . . groove, 60 . . . drive device