Waveguide connection structure and waveguide switch using the same

Abstract

To effectively inhibit leakage of an electromagnetic wave from a clearance in a connection location between a standard waveguide and a gap waveguide.SOLUTION: A waveguide connection structure 100 between a standard waveguide and a gap waveguide comprises: a base block 10 which has a top surface 10a provided with a lower groove 14 including first and second grooves connected to each other and which has a plurality of metal pins 15 periodically arranged on both the sides of the second lower groove; a stationary block 20 which has an undersurface 20c provided with a waveguide formation groove 21 and which has the waveguide formation groove arranged in a facing manner in the first lower groove of the base block so as to form a standard waveguide; and a movable block 30 which has an undersurface 30c covering the second lower groove and the plurality of metal pins in an upper position away from them and which forms the gap waveguide. A third end surface 20a of the stationary block and a fifth end surface 30a of the movable block are arranged in the state of facing each other in parallel at an interval. A partially elliptical choke groove 22 surrounding an opening of the waveguide in an upper part from the top surface of the base block is formed on the third end surface of the stationary block.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a waveguide connection structure and a waveguide switch using the same. [Background technology]

[0002] In order to cope with the expected further increase in mobile traffic in the future, there is a strong demand for the use of millimeter wave and terahertz wave bands for wireless communication, which can achieve transmission speeds of several tens of Gbps. For example, IEEE802.15.3d is considering the use of 252 to 325 GHz.

[0003] For example, a rectangular waveguide with inner dimensions of 0.864 mm × 0.432 mm is used as a propagation path for propagating electromagnetic waves in the WR-3 band (220 to 325 GHz). In various devices using such a rectangular waveguide, a movable part having at least one waveguide is disposed between the input and output waveguides, and the propagation path of the electromagnetic waves is switched by sliding this (for example, see Patent Document 1 and Patent Document 2).

[0004] In the conventional sliding waveguide switch disclosed in Patent Document 1, gaps are provided between the input and output waveguides and the movable part to suppress mechanical wear, and rectangular choke grooves are provided at the openings of the input and output waveguides and the opening of the waveguide in the movable part to reduce leakage of electromagnetic waves from these gaps.

[0005] Furthermore, in the conventional sliding waveguide switch disclosed in Patent Document 2, a so-called gap waveguide in which metal pins are periodically arranged on both sides of the waveguide is adopted as the movable part provided between the input and output waveguides, and a configuration is described that suppresses mechanical wear in the movable part. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6185455 [Patent Document 2] US Patent Application Publication No. 2020 / 0381793 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional sliding waveguide switch disclosed in Patent Document 1, even if a wideband choke groove is provided, if the position of the waveguide of the movable part is deviated from a predetermined stop position, an unintended reflection point occurs due to this deviation. As a result, there was a problem that the reflection characteristics and transmission characteristics change sensitively even with a slight deviation in the position of the waveguide, and for example, a drop occurs in the transmission characteristics, which can significantly impair the wideband characteristics.

[0008] In addition, in the conventional sliding waveguide switch disclosed in Patent Document 2, although a gap waveguide is used in the movable part, it has the same problem as Patent Document 1 in that the waveguide in the movable part may deviate from a predetermined stopping position, and in addition, no consideration is given to effectively suppressing leakage of electromagnetic waves from the connection points between the input / output waveguides and the gap waveguide.

[0009] The present invention has been made to solve such conventional problems, and has an object to provide a waveguide connection structure that can effectively suppress leakage of electromagnetic waves from gaps at the connection points between standard input / output waveguides and the gap waveguide of the movable part, and that has excellent broadband performance, and a waveguide switch using the same. [Means for solving the problem]

[0010] In order to achieve the above object, the waveguide connection structure according to the present invention is a waveguide connection structure (100) between a first waveguide (120) and a second waveguide (130), comprising: a base block (10) having a lower groove (14) formed in an upper surface (10a) from a first end surface (10b) to a second end surface (10c) opposed to the first end surface, the lower groove including a first lower groove (14a) and a second lower groove (14b) connected to each other in a groove longitudinal direction, the base block (10) having a plurality of metal pins (15) periodically arranged on both sides of the second lower groove on either side of the second lower groove on the upper surface; and a waveguide-forming groove (21) formed in a lower surface (20c) from a third end surface (20a) to a fourth end surface (20b) opposed to the third end surface, the base block being disposed on the upper surface so that the waveguide-forming groove faces the first lower groove of the base block. the movable block (30) has a lower surface (30c) spaced apart from upper surfaces of the plurality of metal pins of the base block and covering the upper surface of the second lower groove, and the fixed block (20) forms the second waveguide having a first waveguide (121) on the second lower groove, the third end surface of the fixed block and the fifth end surface (30a) of the movable block being arranged in parallel facing each other with a predetermined gap (G) therebetween, and a partially elliptical choke groove (22) is formed in the third end surface of the fixed block, surrounding an opening of the first waveguide from the upper surface of the base block upward.

[0011] The waveguide connection structure according to the present invention is a connection structure between a standard first waveguide such as a rectangular waveguide and a second waveguide (called a gap waveguide) in which metal pins are periodically arranged on both sides of the waveguide, and a partially elliptical choke groove is formed on the third end face of the fixed block from the upper surface of the base block to the upper part surrounding the opening of the first waveguide. With this configuration, it is possible to effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard waveguide and the gap waveguide.

[0012] Furthermore, in the waveguide connection structure according to the present invention, it is preferable that a configuration be adopted in which an inner-groove protrusion (23) protruding into the choke groove is formed on the side wall surface on the inner periphery of the choke groove in correspondence with a corner (21 c) of an end opening formed by the bottom wall surface and the side wall surface of the waveguide forming groove.

[0013] With this configuration, the waveguide connection structure according to the present invention can eliminate unwanted resonance modes occurring between the first waveguide and the choke groove, and effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard waveguide and the gap waveguide.

[0014] In the waveguide connection structure according to the present invention, the choke groove preferably has a depth (D) equivalent to ¼ of a guide wavelength corresponding to a frequency to be prevented from leaking.

[0015] With this configuration, the waveguide connection structure of the present invention can effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard waveguide and the gap waveguide, by canceling out the electromagnetic waves corresponding to the frequency to be prevented from leaking toward the bottom wall surface of the choke groove and the electromagnetic waves reflected from the bottom wall surface.

[0016] Furthermore, in the waveguide connection structure according to the present invention, a distance (t1) between an end opening of the waveguide formation groove and the choke groove may be set to 1 / 4 of the in-guide wavelength corresponding to the target frequency for leakage prevention at least in the minor axis direction of an ellipse (e1, e2) that is centered on the center of the opening of the first waveguide, has a major axis direction parallel to a long side of the opening, and defines a planar shape of the choke groove.

[0017] With this configuration, the waveguide connection structure of the present invention can effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard waveguide and the gap waveguide, by canceling out the electromagnetic waves corresponding to the frequency to be prevented from leaking from the opening of the first waveguide toward the choke groove and the electromagnetic waves reflected from the side wall surface of the choke groove.

[0018] Furthermore, in the waveguide connection structure according to the present invention, a configuration may be adopted in which a plurality of grooves (22-1, ..., 22-5) of the same width are arranged in parallel at equal intervals on the third end face of the fixed block outside the choke groove with respect to the opening of the first waveguide.

[0019] With this configuration, the waveguide connection structure of the present invention has a multiple cancellation effect of leakage electromagnetic waves, and can effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard waveguide and the gap waveguide.

[0020] The waveguide connection structure of the present invention, which is appropriately equipped with all or some of the above-mentioned configurations, can suppress electromagnetic wave leakage to -15 dB or less over the entire operating frequency range of a standard rectangular waveguide (fractional bandwidth 40%) for gaps up to about 1 / 20 of the guide wavelength corresponding to the target frequency for leakage prevention.

[0021] Furthermore, a waveguide switch according to the present invention is a waveguide connection structure (100) between a first waveguide (120), a second waveguide (130), and a third waveguide (140), comprising: a base block (10) having an upper surface (10a) provided with a lower groove (14) extending from a first end surface (10b) to a second end surface (10c) opposing the first end surface, the lower groove including a first lower groove (14a), a second lower groove (14b), and a third lower groove (14c) connected in sequence in the groove longitudinal direction, and having a plurality of metal pins (15) periodically arranged on both sides of the second lower groove on either side of the second lower groove on the upper surface; a first fixed block (20) having a first waveguide forming groove (21) extending from a third end face (20a) to a fourth end face (20b) opposed to the third end face, the first fixed block (20) being disposed on the upper surface such that the first waveguide forming groove faces the first lower groove of the base block, and forming the first waveguide having a first waveguide (121); a movable block (30) having a lower surface (30c) spaced apart from upper surfaces of the plurality of metal pins of the base block and covering the plurality of metal pins and the second lower groove, and forming the second waveguide having a second waveguide (131) on the second lower groove; a second fixed block (40) having a third waveguide (141) formed on the upper surface such that the second waveguide forming groove faces the third lower groove of the base block, the second fixed block (40) being provided with a seventh end face (40a) through an eighth end face (40b) opposed to the seventh end face (40a), the second fixed block (40) being disposed on the upper surface such that the second waveguide forming groove faces the third lower groove of the base block, the second fixed block (40) forming the third waveguide having a third waveguide (141); the waveguide connection structure has a sixth end face (30b) disposed opposite the row of the first fixed block, and a partially elliptical choke groove (22) surrounding an opening of the first waveguide or the third waveguide from the top surface of the base block to an upper portion of the third end face (30b) of the second fixed block, and a drive unit (60) that slides and moves the movable block, the lower surface (30c) of the movable block being provided with a protrusion (31) of a size capable of moving between the rows of the plurality of metal pins, and the drive unitthe protrusion of the movable block is located in a storage area outside the plurality of metal pins with respect to the second waveguide; On state and the protrusion of the movable block is located within the second waveguide. Off state The movable block is slidably moved so as to be switchable between the above and the above.

[0022] As described above, the waveguide switch according to the present invention fixes the first and third waveguides corresponding to standard input and output waveguides and the base block constituting the gap waveguide body in a predetermined positional relationship, and allows only the movable block provided with the protrusions to slide. With this configuration, it is possible to arrange the protrusions, which are thinner than the gaps between the periodically arranged metal pins, either in the storage area where no metal pins are provided or in the waveguide of the gap waveguide, and therefore the switch can function as a single-pole single-throw (SPST) switch that switches between transmitting and blocking electromagnetic waves.

[0023] In this way, in the waveguide switch according to the present invention, the position of the gap waveguide connecting the first waveguide and the third waveguide is fixed, so that unintended reflection points caused by misalignment between the waveguides, as seen in conventional sliding waveguide switches, do not occur, and therefore the waveguide switch according to the present invention can function as a waveguide switch with excellent broadband performance.

[0024] Furthermore, by using the above-mentioned waveguide connection structure of the present invention in the movable part of the waveguide switch, the waveguide switch of the present invention can suppress unintended leakage of electromagnetic waves from gaps at the waveguide connection points between input and output ports, and can reduce the transmission loss of the switch over a wide band. Effect of the Invention

[0025] According to the present invention, it is possible to provide a waveguide connection structure that can effectively suppress leakage of electromagnetic waves from the connection points between standard input / output waveguides and a gap waveguide of a movable part and has excellent broadband performance, and a waveguide switch using the same. [Brief description of the drawings]

[0026] [Figure 1] 1 is an exploded perspective view of a waveguide switch and a waveguide connection structure according to an embodiment of the present invention, as viewed obliquely from above. [Diagram 2] 1 is an exploded perspective view of a waveguide switch and a waveguide connection structure according to an embodiment of the present invention, as viewed obliquely from below (a driving device is omitted). [Diagram 3] FIG. 3 is a plan view of the base block of FIG. 1 and FIG. 2. [Figure 4] FIG. 4 is a partial enlarged view showing an example of a configuration of a choke groove according to an embodiment of the present invention. [Diagram 5] 1A, 1B, and 1C are diagrams showing the configuration of a waveguide switch according to an embodiment of the present invention in an ON state, where FIG. 1A is a front view, FIG. 1B is a right side view, and FIG. [Figure 6] 1A, 1B, and 1C are diagrams showing the configuration of a waveguide switch according to an embodiment of the present invention in an OFF state, where FIG. 1A is a front view, FIG. 1B is a right side view, and FIG. [Figure 7] (a) shows a simulation model in which rectangular parallelepiped-shaped metal pins are arranged in an infinite periodic manner on a base block, and (b) shows the size of each rectangular parallelepiped-shaped metal pin in this simulation model. [Figure 8] 8 is a graph showing dispersion characteristics when an electromagnetic wave is irradiated perpendicularly to a side surface of a metal pin in the simulation model shown in FIGS. 7(a) and 7(b). [Figure 9] 1A and 1B are graphs showing simulation results of the reflection and transmission characteristics of a waveguide switch according to an embodiment of the present invention, in which (a) shows the reflection and transmission characteristics in an ON state, and (b) shows the reflection and transmission characteristics in an OFF state. [Figure 10] FIG. 1A is a perspective view showing a comparative example of a waveguide connection structure, and FIG. 1B is a graph showing a simulation result of the in-plane distribution of the electric field in a gap of the waveguide connection structure of FIG. [Figure 11]FIG. 3 is a diagram showing an example of a simulation model of a choke groove in the waveguide connection structure according to the first embodiment of the present invention. [Figure 12] 1 shows the results of a simulation of transmitted and reflected power characteristics in a waveguide connection structure according to a first embodiment of the present invention, where (a) is a graph showing the simulation results of return loss, (b) is a graph showing the simulation results of insertion loss, and (c) is a graph showing the simulation results of electromagnetic wave leakage from gaps in the waveguide connection structure. [Figure 13] 7A and 7B are diagrams illustrating an example of the configuration of a choke groove in a waveguide connection structure according to a second embodiment of the present invention. [Figure 14] FIG. 11 is a diagram showing an example of a simulation model of a choke groove in a waveguide connection structure according to a second embodiment of the present invention. [Figure 15] 13A shows the results of simulating transmitted and reflected power characteristics by changing the number of grooves in a waveguide connection structure according to a second embodiment of the present invention, where (a) is a graph showing the simulation results of return loss, (b) is a graph showing the simulation results of insertion loss, and (c) is a graph showing the simulation results of electromagnetic wave leakage from gaps in the waveguide connection structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a waveguide switch and a waveguide connection structure according to the present invention will be described with reference to the drawings.

[0028] (First embodiment) 1 and 2 are exploded perspective views of a waveguide switch 1 using a waveguide connection structure 100 according to a first embodiment of the present invention. Note that in Fig. 2, the driver 60 is omitted from the illustration.

[0029] 1 and 2, the waveguide switch 1 according to this embodiment includes a base block 10, a first fixed block 20, a movable block 30, a second fixed block 40, and a drive unit 60. The base block 10, the first fixed block 20, the movable block 30, and the second fixed block 40 are made of metal materials such as brass, aluminum, copper, and gold. Of these metal materials, aluminum is particularly preferable because it is easy to process, is inexpensive, and can have a small surface roughness.

[0030] Waveguide switch 1 is an SPST switch for switching between transmitting and blocking electromagnetic waves between first waveguide 121 and third waveguide 141. For example, first waveguide 121 and third waveguide 141 have inner dimensions of 0.864 mm×0.432 mm and constitute a WR-3 waveguide that transmits the WR-3 band (220 to 325 GHz).

[0031] <Base block> The base block 10 is formed in a rectangular plate shape or a rectangular parallelepiped shape in plan view seen from above in the Y-axis direction, with a first fixed block 20 fixed to one end of its top surface 10a and a second fixed block 40 fixed to the other end. Between the first fixed block 20 and the second fixed block 40, a movable block 30 is slidably disposed.

[0032] FIG. 3 is a plan view of the base block 10. The base block 10 has a first area 11, a second area 12, and a third area 13, each of which is rectangular in plan view, arranged in this order on the upper surface 10a. In addition, a lower groove 14 is formed on the upper surface 10a, which intersects the first area 11, the second area 12, and the third area 13 in order at approximately the center thereof. Specifically, the lower groove 14 is provided on the upper surface 10a in a direction perpendicular to the opposing first end surface 10b and second end surface 10c, from the first end surface 10b to the second end surface 10c, and the lower groove 14 includes a first lower groove 14a, a second lower groove 14b, and a third lower groove 14c, which are connected in order in the groove longitudinal direction (Z-axis direction), and a plurality of metal pins 15 are periodically arranged on both sides of the second lower groove 14b in the second area 12 of the upper surface 10a, sandwiching the second lower groove 14b. The lower groove 14 is a shallow groove, but may be flush with the upper surface 10a. In the first area 11, the first lower groove 14a has flat surfaces on both sides, and in the third area 13, the third lower groove 14c has flat surfaces on both sides.

[0033] In this embodiment, a plurality of metal pins 15 are arranged in three rows and three columns at equal pitch p on both sides of the second lower groove 14b, but the number of columns and the number of rows are not limited to this. The pitch p between the metal pins 15 is equal on both sides of the second lower groove 14b. No metal pins 15 are provided in the second lower groove 14b in the second area 12. A flat storage area 17 is provided between the plurality of metal pins 15 and the protrusion 16 on the outer side of the plurality of metal pins 15 in the second area 12.

[0034] The metal pins 15 are made of a metal material such as brass, aluminum, copper, or gold. The metal pins 15 may be attached to the second area 12 of the upper surface 10a of the base block 10 by, for example, soldering or bonding with a conductive adhesive. Alternatively, the metal pins 15 may be integrally formed as a part of the base block 10. The shape of the metal pins 15 may be any columnar shape, for example, a rectangular parallelepiped shape, a cylindrical shape, or a polygonal column shape such as a hexagonal column.

[0035] The first area 11 of the base block 10, together with the first fixed block 20, forms a first waveguide 120 having a first waveguide 121 (see also Figs. 5(b) and (c)). The second area 12 of the base block 10, together with the movable block 30, forms a gap waveguide 130 having a gap waveguide 131. The second area 12 of the base block 10 is also referred to as a gap waveguide body 12a. The third area 13 of the base block 10, together with the second fixed block 40, forms a third waveguide 140 having a third waveguide 141.

[0036] <First fixed block> As shown in FIG. 1 and FIG. 2, the first fixing block 20 is formed in a rectangular parallelepiped shape having a third end face 20a, a fourth end face 20b, and a lower face 20c that face each other. The lower face 20c is provided with a waveguide forming groove 21 that extends from the third end face 20a to the fourth end face 20b in a direction perpendicular to the third end face 20a and the fourth end face 20b. The waveguide forming groove 21 is a groove whose end opening at the third end face 20a has a width wa and a depth wb. The first fixing block 20 is disposed in the first area 11 of the upper face 10a of the base block 10 so that the waveguide forming groove 21 faces the first lower groove 14a in the first area 11 of the base block 10, forming a first waveguide 120 having a first waveguide 121 (see also FIG. 5(b) and (c)). The first waveguide 121 is a standard rectangular waveguide with a rectangular cross section in which the inside of the waveguide is surrounded by a metal wall.

[0037] 4, a partially elliptical choke groove 22 is formed in the third end face 20a of the first fixing block, surrounding the opening of the first waveguide 121 from the upper surface 10a of the base block 10 upward. An inner groove protrusion 23 of width w3 is formed in the side wall surface 22a on the inner periphery of the choke groove 22, protruding into the choke groove 22 at an angle θ (angle with respect to the long side of the end opening) in correspondence with a corner 21c of the end opening formed by the bottom wall surface 21b and side wall surface 21a of the waveguide forming groove 21. The choke groove 22 has a depth D equivalent to ¼ of the guide wavelength corresponding to the frequency to be prevented from leaking.

[0038] As will be described later with reference to FIG. 11, the interval between the end opening of the waveguide formation groove 21 and the choke groove 22 is set to an interval t1 equivalent to ¼ of the in-guide wavelength corresponding to the target frequency for leakage prevention, at least in the minor axis direction of the inner ellipse e1 and the outer ellipse e2 which define the planar view shape of the choke groove 22.

[0039] <Second fixed block> As shown in FIG. 1 and FIG. 2, the second fixed block 40, like the first fixed block 20, is formed in a rectangular parallelepiped shape having a seventh end face 40a, an eighth end face 40b, and a lower face 40c that face each other. The lower face 40c is provided with a waveguide forming groove 41 extending from the seventh end face 40a to the eighth end face 40b in a direction perpendicular to the seventh end face 40a and the eighth end face 40b. The second fixed block 40 is disposed in the third area 13 of the upper face 10a of the base block 10 so that the waveguide forming groove 41 faces the third lower groove 14c in the third area 13 of the base block 10, forming a third waveguide 140 having a third waveguide 141 (see also FIG. 5(b) and (c)). The third waveguide 141 has the same cross-sectional shape and cross-sectional size as the first waveguide 121. The third waveguide 141 is formed on a line that passes through the center of the first waveguide 121. The third waveguide 141 is a standard rectangular waveguide with a rectangular cross section, the inside of which is surrounded by a metal wall.

[0040] The seventh end face 40a of the second fixed block 40 is also provided with the same choke structure (that is, the choke groove and the protrusion in the groove) as the first fixed block 20, but may be configured without providing the choke structure.

[0041] <Movable block> 1 and 2, the movable block 30 is formed in a rectangular parallelepiped shape having a fifth end face 30a and a sixth end face 30b facing each other and a bottom face 30c. Specifically, the movable block 30 has a fifth end face 30a arranged to face the third end face 20a of the first fixed block 20 with a predetermined gap G therebetween, a sixth end face 30b arranged to face the seventh end face 40a of the second fixed block 40 with a predetermined gap G therebetween, and a bottom face 30c that is spaced apart from the top face 15a of the plurality of metal pins 15 in the second area 12 of the base block 10 and covers the top of the plurality of metal pins 15 and the second lower groove 14b, and forms a second waveguide having a second waveguide 131 on the second lower groove 14b (see also FIG. 5). The movable block 30 is configured to be slidable in parallel with respect to the second area 12 of the base block 10, the third end face 20a of the first fixed block 20, and the seventh end face 40a of the second fixed block 40.

[0042] The lower surface 30c of the movable block 30 is provided with a protrusion 31 having a size that allows the protrusion 31 to move between the rows of the metal pins 15 in a direction perpendicular to the longitudinal direction of the second waveguide 131. Specifically, the movable block 30 has the protrusion 31 on the lower surface 30c, the protrusion 31 having a thickness smaller than the gap between the metal pins 15 adjacent to each other in the propagation direction of the electromagnetic wave (Z-axis direction). Here, the "thickness of the protrusion 31" refers to the thickness of the waveguide switch 1 in the propagation direction of the electromagnetic wave (Z-axis direction). The protrusion 31 is made of a metal material such as brass, aluminum, copper, or gold. The protrusion 31 may be disposed on the lower surface 30c by, for example, soldering or bonding with a conductive adhesive. Alternatively, the protrusion 31 may be disposed on the lower surface 30c by being integrally formed as a part of the movable block 30.

[0043] The protrusion 31 has, for example, a rectangular parallelepiped shape, and the width w4 and height h4 of the surface perpendicular to the propagation direction of the electromagnetic wave in the waveguide switch 1 (Z-axis direction) and the thickness t4 in the propagation direction of the electromagnetic wave (z-axis direction) can be appropriately set to values ​​that do not generate unnecessary resonance modes in the waveguide switch 1.

[0044] Next, a simulation result of the propagation characteristic distribution of electromagnetic waves in a gap waveguide in which metal pins 15 are provided on both sides of the waveguide will be described. Fig. 7(a) shows a simulation model in which rectangular parallelepiped metal pins 15 are arranged at an infinite period on a base block 10. Fig. 7(b) shows the size of each rectangular parallelepiped metal pin 15 in the simulation model of Fig. 7(a).

[0045] The gap width g between the lower surface 30c of the movable block 30 and the upper surface 15a of the metal pin 15, the pitch p of the metal pins 15, the height h of the metal pins 15, and the width w of the metal pins 15 are, for example, as follows. Gap width g=λ c / 20=0.06245mm Metal pin pitch p=λ c / 3=0.4163mm Metal pin height h=λ c / 4=0.3123mm Metal pin width w=λ c / 6=0.2082mm Here, λ c is the free space wavelength corresponding to the center frequency of the ideal propagation stop band. For example, when the center frequency is 240 GHz, λ c =1.249mm.

[0046] Fig. 8 shows the dispersion characteristics when an electromagnetic wave is irradiated perpendicularly to the side surface of the metal pin 15 using the parameters related to the metal pin 15 in the simulation model shown in Figs. 7(a) and (b). This simulation result shows that no propagation mode occurs in the propagation stop band of 146 to 366 GHz, and the propagation of the electromagnetic wave is blocked. Since the WR-3 band falls within this propagation stop band, it can be seen that by using the parameters related to the metal pin 15 described above, a gap waveguide that functions as a WR-3 waveguide can be configured.

[0047] In this embodiment, the base block 10 and the movable block 30 form a gap waveguide (second waveguide) 130. The gap waveguide 130 has a gap waveguide (second waveguide) 131 formed by being surrounded by a plurality of metal pins 15, the second lower groove 14b of the second area 12 of the base block 10, and the lower surface 30c of the movable block 30. In the region where the plurality of metal pins 15 are periodically arranged, the propagation of electromagnetic waves is blocked and electromagnetic field energy is trapped, whereas in the gap waveguide 131 where the plurality of metal pins 15 are not arranged, the electromagnetic waves can propagate.

[0048] The cross-sectional shape and size of the gap waveguide 131 are the same as those of the first waveguide 121 and the third waveguide 141. The gap waveguide 131 is formed on a line passing through the centers of the first waveguide 121 and the third waveguide 141. That is, the distance between the bottom surface of the second lower groove 14b of the second area 12 of the base block 10 and the lower surface 30c of the movable block 30 is equal to the width of the short side direction of the rectangular opening of the first waveguide 121 and the third waveguide 141. Moreover, the width of the second lower groove 14b of the second area 12 where the multiple metal pins 15 are not provided is equal to the width of the long side direction of the rectangular opening of the first waveguide 121 and the third waveguide 141. For example, the first waveguide 121 and the third waveguide 141 have an inner dimension of 0.864 mm×0.432 mm and constitute a WR-3 waveguide that has a transmission band in the WR-3 band (220 to 325 GHz).

[0049] The gap waveguide 130 in this embodiment has a structure in which the side portion of the waveguide of a standard metal waveguide is replaced with a conductive wall, but with a number of periodically arranged metal pins 15. As with the upper portion of the gap waveguide 131, the upper surface 15a of the metal pin 15 faces the lower surface 30c of the movable block 30 with an air gap between them, so there is no metal contact between the base block 10 and the movable block 30.

[0050] That is, the waveguide switch 1 of this embodiment has a feature that it does not require metallic contact between the base block 10 and the movable block 30. Therefore, it is possible to fix the first waveguide 120 and the third waveguide 140, which are normal input / output waveguides, and the gap waveguide 130 in a predetermined positional relationship, and to slide only the movable block 30 without mechanical wear.

[0051] In addition, the portion of the gap waveguide 131 that corresponds to the tube wall along the electromagnetic wave propagation direction (Z-axis direction) has a structure in which a plurality of metal pins 15 are periodically arranged, so that the protrusion portion 31, which is a structure thinner than the gap between adjacent metal pins 15, can be inserted and removed through that gap.

[0052] <Drive unit> Next, the driving device 60 for sliding the movable block 30 will be described.

[0053] 5(a) to (c) show a state in which the protrusion 31 of the movable block 30 is disposed in a storage region 58 sandwiched between a storage area 17 in which no metal pin 15 is provided in the second area 12 of the base block 10 and the lower surface 30c of the movable block 30. FIG. 5(a) is a front view seen with the second fixed block 40 removed, FIG. 5(b) is a right side view, and FIG. 5(c) is a plan view. The states shown in FIGS. 5(a) to (c) are a connection state in which the waveguide switch 1 allows transmission of electromagnetic waves between the first waveguide 121 and the third waveguide 141 (hereinafter also referred to as an "ON state" or "ON state").

[0054] 6(a) to (c) show a state in which the protrusion 31 is disposed at the position of the gap waveguide 131, and an electromagnetic wave input from the first waveguide 121 or the third waveguide 141 is reflected by the protrusion 31. FIG. 6(a) is a front view with the second fixing block 40 removed, FIG. 6(b) is a right side view, and FIG. 6(c) is a plan view. That is, the states shown in FIGS. 6(a) to (c) are a non-connected state (hereinafter also referred to as an "OFF state") in which the waveguide switch 1 can block the propagation of electromagnetic waves between the first waveguide 121 and the third waveguide 141.

[0055] In the driving device 60 shown in FIG. 1, the protrusion 31 of the movable block 30 is located in the storage area 58 outside the plurality of metal pins 15 with respect to the second waveguide 131. On state Then, the protrusion 31 of the movable block 30 is positioned within the second waveguide 131. Off state The movable block 30 is slidably moved so that the position can be switched between the above and the below.

[0056] The movable block 30 is supported by the driving device 60 so as to be slidable relative to the base block 10. The structure of the driving device 60 is arbitrary, but it may be configured so as to detect the position and movement distance of the movable block 30 by a sensor, an encoder, or the like, and selectively move the movable block 30 to a position that realizes the ON state or the OFF state. In this way, the waveguide switch 1 according to this embodiment functions as an SPST switch for switching between transmitting and blocking the electromagnetic wave between the first waveguide 121 and the third waveguide 141.

[0057] <Waveguide connection structure> Next, a waveguide connection structure 100 used in the waveguide switch 1 will be described.

[0058] The waveguide connection structure 100 is a structure for connecting the first waveguide 120 and the gap waveguide 130, or a structure for connecting the third waveguide 140 and the gap waveguide 130. For simplicity, the structure for connecting the first waveguide 120 and the gap waveguide 130 will be described below, but the same applies to the structure for connecting the third waveguide 140 and the gap waveguide 130.

[0059] As shown in Figures 1 to 6, a waveguide connection structure 100 according to an embodiment of the present invention has a structure in which a third end face 20a of a first fixed block 20, which forms a standard first waveguide 120 together with a base block 10, and a fifth end face 30a of a movable block 30, which forms a gap waveguide 130 together with the base block 10, face each other in parallel with a predetermined gap G therebetween.

[0060] The third end face 20a of the first fixed block 20, which constitutes the first waveguide 120 together with the base block 10, is provided with a choke groove 22 at a position surrounding the periphery of the rectangular end opening of the waveguide forming groove 21 to prevent electromagnetic wave leakage from the gap G between the third end face 20a and the fifth end face 30a.

[0061] (Comparative Example) Fig. 10(a) shows a simulation model of a comparative example, and is a perspective view showing a waveguide connection structure in which a standard waveguide 70 without a choke groove and a gap waveguide 80 are arranged in parallel facing each other with a predetermined gap G. The waveguide 70 and the gap waveguide 80 correspond to WR-3 waveguides that have a transmission band in the WR-3 band. Fig. 10(b) shows a simulation result of the in-plane distribution of the electric field in the simulation model of Fig. 10(a) when the operating frequency is 280 GHz and the gap G is 300 μm.

[0062] 10(b), it was found that the wavefront (constant phase line) at 280 GHz of the electromagnetic wave radiated from waveguide 70 without a choke groove into gap G has a phase shift of approximately 180° between the gap side region (the region above the part where the metal pins and waveguides are aligned horizontally at the center in the figure) and the pin side region (the region below the part where the metal pins and waveguides are aligned horizontally at the center in the figure) due to the presence of gap waveguide 80. The shape of the wavefront is flatter in the gap side region than in the pin side region, and both the gap side region and the pin side region are approximately circular at a distance of one wavelength or more from waveguide 70, but is close to an ellipse near waveguide 70.

[0063] From the simulation results in FIG. 10(b), it is inferred that the presence of gap waveguide 80 causes a phase shift of approximately 180° between the gap side region and the pin side region, and that the shapes are slightly different, so that it is preferable to have different choke structures for the gap side region and the pin side region.

[0064] (Study of waveguide connection structure) In response to the simulation results of the comparative example, in order to consider a simpler choke structure, a model in which the pin side region is a conductor wall and a choke structure is provided in the gap side region is considered.

[0065] FIG. 11 shows a simulation model in which an elliptical choke structure is provided only in the gap side region. In the simulation model of FIG. 11, the choke groove 22 is formed in a band-like region bounded by an inner ellipse e1 and an outer ellipse e2 whose major axis direction is parallel to the long side of the rectangular opening of the first waveguide 121 and whose center is the center O of the rectangular opening of the first waveguide 121 in a plan view. The choke groove 22 is a partial ellipse surrounding the opening of the first waveguide 121, and the "partial ellipse" means that the inner ellipse e1 and the outer ellipse e2 that define the boundary of the choke groove 22 are not the entire ellipse, but are a part of an ellipse limited to the range up to the bottom surface 20c of the first fixing block 20. Thus, the choke groove 22 is formed in the third end surface 20a of the first fixing block 20 so that one end side starts from the bottom surface 20c and the other end side ends at the bottom surface 20c. Since leakage of electromagnetic waves below the upper surface 10a of the base block 10 is suppressed by the base block 10, leakage of electromagnetic waves can be effectively suppressed by the partially elliptical choke groove 22 provided above the upper surface 10a of the base block 10.

[0066] 4 and 11, the side wall surface of the choke groove 22 is perpendicular to the third end face 20a. The depth D of the choke groove 22 is set to a value equal to the guide wavelength λ corresponding to the target frequency for leakage prevention. g In this embodiment, the leakage prevention target frequency is 272.5 GHz, which is the center frequency of the WR-3 band (220 to 325 GHz). At this time, the guide wavelength λ g is approximately 1.43 mm. Here, the wavelength in the tube, λ g The depth equivalent to 1 / 4 of the wavelength in the tube, λ g In this specification and claims, the term "tube wavelength λ" refers to a depth in the range of ±20% of 1 / 4 of the g When we say "1 / 4 of the wavelength," we mean the wavelength in the tube, λ gThe leakage prevention target frequency is not limited to the above-mentioned value, but may be any frequency within the WR-3 band or any other desired frequency band according to the sizes of the first waveguide 120 and the second waveguide 130.

[0067] The width w2 of the choke groove 22 is set to be equal to the wavelength λ g Here, the wavelength in the tube, λ g The width equivalent to 1 / 4 of the wavelength in the tube, λ g The width of the choke groove 22 is equal to the difference between the minor radius of the outer ellipse e2 and the minor radius of the inner ellipse e1, and the difference between the major radius of the outer ellipse e2 and the major radius of the inner ellipse e1.

[0068] In terms of geometrical optics, if a curved mirror aligned with the equiphase surface of the electromagnetic wave is placed on the propagation path of the electromagnetic wave, the reflected wave of the electromagnetic wave reflected by the curved mirror will travel in the opposite direction to the propagation direction of the incident wave of the electromagnetic wave that is incident on the curved mirror. For this reason, if an elliptical curved mirror (choke groove 22) is formed that is aligned with the equiphase surface of the radiation wave that leaks from first waveguide 121 into gap G and does not directly enter first waveguide 121, the reflected wave of the radiation wave at choke groove 22 will be in opposite phase to the incident wave of the radiation wave, and they will cancel each other out. In other words, it is presumed that the choke groove 22 can suppress unnecessary radiation waves.

[0069] A partition portion 24 is provided on the third end face 20a of the first fixed block 20 to separate the first waveguide 121 and the choke groove 22, and the partition portion 24 has an end face 24a that is flush with the third end face 20a. Two in-groove protrusions 23, 23 are formed on the outer peripheral side wall surface of the partition portion 24 (i.e., the inner peripheral side wall surface 22a of the choke groove 22) extending in a direction away from the opening of the first waveguide 121 along the diagonal direction of the opening of the first waveguide 121. The angles θ that the extension directions of the two in-groove protrusions 23, 23 make with the major axes of the inner peripheral ellipse e1 and the outer peripheral ellipse e2 are the same. The width w3 in the direction perpendicular to the extension direction of the in-groove protrusion 23 is set to be equal to the in-guide wavelength λ corresponding to the target frequency for leakage prevention. g Here, the wavelength in the tube, λ gThe width equivalent to 1 / 4 of the wavelength in the tube, λ g This refers to a range of ±20% of 1 / 4 of the standard deviation.

[0070] Further, the interval t1 between the end opening of the waveguide formation groove 21 and the choke groove 22 is set to be equal to or smaller than the in-guide wavelength λ corresponding to the target frequency for leakage prevention in at least the minor axis direction of an ellipse (i.e., the inner peripheral ellipse e1 and the outer peripheral ellipse e2) that is centered on the center O of the opening of the first waveguide 121, has its major axis direction parallel to the long side of the opening, and defines the planar shape of the choke groove 22. g The wavelength in the tube is set to approximately 1 / 4 of the wavelength. g The interval equivalent to 1 / 4 of the tube wavelength λ g The distance t2 between the short side of the end opening of the waveguide groove 21 and the choke groove 22 is within the range of 1 / 4 of the guide wavelength λ g The wavelength in the tube is 1 / 8 of the wavelength λ g The interval equivalent to 1 / 8 of the tube wavelength λ g This refers to an interval in the range of ±20% of 1 / 8 of the normal.

[0071] An example of the dimensions of the choke groove 22 in the waveguide connection structure 100 of this embodiment is as follows (see FIGS. 4 and 11). Width of choke groove 22 (w2): 0.3617mm Depth of choke groove 22 (D): 0.286mm Distance between the end opening of the waveguide forming groove 21 and the choke groove 22 (t1): 0.286 mm Distance between the end opening of the waveguide forming groove 21 and the choke groove 22 (t2): 0.1415 mm - Minor radius of inner ellipse e1 (r1): 0.502 mm · The semimajor axis of the inner ellipse e1 (r2): 0.5735 mm - Minor radius of outer ellipse e2 (r3): 0.8637 mm · Major axis of outer ellipse e2 (r4): 0.9352 mm Width of groove protrusion 23 (w3): ​​0.312 mm Angle (θ) between the extension direction of the inner groove protrusion 23 and the major axis of the inner ellipse e1: 20° Gap (G) between the third end surface 20a and the fifth end surface 30a: 0.05 mm

[0072] FIG. 12 is a graph showing the reflection characteristic S between the first waveguide 121 and the second waveguide 131 in the waveguide connection structure 100, which is calculated using the simulation model shown in FIG. 11 , transmission characteristic S 21 1 shows the simulation results of the leakage rate of electromagnetic waves, and the gap G between the standard first waveguide 120 and the gap waveguide 130 is set to 0.05 mm (50 μm).

[0073] In this simulation, an electromagnetic wave is assumed to be incident from the gap waveguide 130 on the port P1 side toward the first waveguide 120 on the port P2 side shown in Fig. 10. Here, leakage is expressed by the following formula (1).

[0074] Leak (dB) = 10log{1-(|S 11 | 2 +|S 21 | 2 )} ···(1)

[0075] As shown in Fig. 12(a), the return loss S 11 It was confirmed that the insertion loss S 21 It was confirmed that, over the WR-3 band, the leakage of electromagnetic waves from between the first waveguide 121 and the gap waveguide 131 was suppressed to less than -15 dB.

[0076] In addition, even if the port P1 side is the first waveguide 120 and the port P2 side is the gap waveguide 130, the reflection loss S between the first waveguide 121 and the gap waveguide 131 is 11 , insertion loss S 21 There was no change in the values ​​of , and leakage.

[0077] As described above, the waveguide connection structure 100 according to this embodiment has a guide wavelength λ 2 corresponding to a frequency to be prevented from leaking. g For a given gap G of up to about 1 / 20 of the WR-3 waveguide, the return loss S 11 to less than -15 dB, and the insertion loss S 21 The absolute value of the interference can be kept below 0.25 dB, and the electromagnetic wave leakage can be kept below -15 dB.

[0078] <Switch operation simulation> Next, a simulation result of the switching operation of the waveguide switch 1 using the waveguide connection structure 100 according to this embodiment will be described.

[0079] FIG. 9(a) shows the reflection characteristic S between the first waveguide 121 and the gap waveguide 131 in the ON state configuration shown in FIGS. 5(a) to 5(c). 11 and transmission characteristic S 21 9(b) shows the simulation result of the reflection characteristic S between the first waveguide 121 and the gap waveguide 131 in the OFF state configuration shown in FIGS. 11 and transmission characteristic S 21 In these simulations, it is assumed that an electromagnetic wave propagates from the first waveguide 121 to the gap waveguide 131.

[0080] The simulation conditions are as follows. The size of the metal pin 15 is the same as that in the simulation model shown in Figures 7(a) and (b). The size of the choke groove 22 is the same as that described above with reference to Figure 11. Width of protrusion 31 (w4): 0.4 mm Height of protrusion 31 (h4): 0.3 mm Thickness of protrusion 31 (t4): 0.1 mm Distance (g4) between the upper surface 31a of the protrusion 31 and the bottom surface 17 of the housing: 0.0747 mm Width (a) of the first waveguide 121: 0.864 mm Height (b) of the first waveguide 121: 0.432 mm Distance (g) between the upper surface 15a of the metal pin 15 and the lower surface 30c of the movable block 30: 0.06245 mm Distance (g2) between the upper surface 16a of the protrusion 16 and the lower surface 30c of the movable block 30: 0.06245 mm Length of storage area 17 in the X-axis direction (L): 0.6872 mm Distance (g3) between the bottom surface 17 of the storage compartment and the bottom surface 30c of the movable block 30: 0.3747 mm Gap (G) between the third end face 20a and the fifth end face 30a: 0.05 mm

[0081] As shown in Fig. 9(a) and (b), in the WR-3 band (220 to 325 GHz), the transmission characteristic S 21 In contrast, in the OFF state, the transmission characteristic S 21 On the other hand, the reflection characteristic S 11 In contrast, in the OFF state, the reflection characteristic S 11 9(a) and 9(b), it was confirmed that the waveguide switch 1 of this embodiment functions as an SPST switch that can switch between transmitting and blocking electromagnetic waves between an ON state and an OFF state.

[0082] <Action and effect> As described above, in the waveguide connection structure 100 according to this embodiment, in a connection structure between a standard first waveguide 120 such as a rectangular waveguide and a gap waveguide 130 having a plurality of metal pins 15 periodically arranged on both sides of the waveguide, a partially elliptical choke groove 22 is formed in the third end face 20a of the first fixing block 20, surrounding the opening of the first waveguide 121 from the upper face 10a of the base block 10 upward. With this configuration, leakage of electromagnetic waves from the gap G at the connection point between the standard first waveguide 120 and the gap waveguide 130 can be effectively suppressed.

[0083] Furthermore, in the waveguide connection structure 100 according to this embodiment, an in-groove protrusion 23 that protrudes into the choke groove 22 is formed on the side wall surface 22a on the inner periphery of the choke groove 22 in correspondence with a corner 21c of an end opening formed by the bottom wall surface 21b and side wall surface 21a of the waveguide forming groove 21. With this configuration, it is possible to remove an unnecessary resonance mode that occurs between the first waveguide 121 and the choke groove 22, and effectively suppress leakage of electromagnetic waves from the gap G at the connection point between the standard waveguide 120 and the gap waveguide 130.

[0084] In the waveguide connection structure 100 according to this embodiment, the choke groove 22 has a guide wavelength λ 2 corresponding to the target frequency for leakage prevention. g With this configuration, the electromagnetic waves corresponding to the frequency to be prevented from leaking toward bottom wall surface 22c of choke groove 22 and the electromagnetic waves reflected from bottom wall surface 22c cancel each other out, so that leakage of the electromagnetic waves from gap G at the connection point between standard waveguide 120 and gap waveguide 130 can be effectively suppressed.

[0085] In the waveguide connection structure 100 according to this embodiment, the distance t1 between the end opening of the waveguide formation groove 21 and the choke groove 22 is set to be equal to or smaller than the guide wavelength λ corresponding to the target frequency for leakage prevention in the minor axis direction of an ellipse e1, e2 that is centered on the center O of the opening of the first waveguide 121, has its major axis direction parallel to the long side of the opening, and defines the planar shape of the choke groove 22. g With this configuration, the electromagnetic wave corresponding to the frequency to be prevented from leaking, traveling from the opening of first waveguide 121 toward choke groove 22, and the electromagnetic wave reflected from choke groove 22 cancel each other out, so that leakage of the electromagnetic wave from gap G at the connection point between standard waveguide 120 and gap waveguide 130 can be effectively suppressed.

[0086] The waveguide connection structure 100 according to this embodiment has a guide wavelength λ 2 corresponding to a frequency to be prevented from leaking. g For a gap G of up to about 1 / 20 of the gap, the leakage of electromagnetic waves can be suppressed to -15 dB or less over the entire operating frequency range of a standard rectangular waveguide (40% of the relative bandwidth).

[0087] The waveguide switch 1 of this embodiment uses the above-mentioned waveguide connection structure 100 in the movable part of the waveguide switch 1, thereby making it possible to suppress unintended leakage of electromagnetic waves from the gap G at the waveguide connection point between the input and output ports, and to reduce the transmission loss of the switch over a wide band.

[0088] The waveguide switch 1 according to the present embodiment uses the waveguide connection structure 100 according to the present embodiment as the movable part of the waveguide switch 1, and fixes the first waveguide 120 and the third waveguide 140 corresponding to standard input / output waveguides and the base block 10 constituting the gap waveguide body (i.e., the second area 12) in a predetermined positional relationship, and allows only the movable block 30 provided with the protrusions 31 to slide. With this configuration, the protrusions 31, which are thinner than the gaps between the periodically arranged metal pins 15, can be disposed in either the storage area 58 where the metal pins 15 are not provided or in the gap waveguide 131 of the gap waveguide 130, and therefore the waveguide switch can function as an SPST switch that switches between transmission (ON state) and blocking (OFF state) of electromagnetic waves.

[0089] In this way, in the waveguide switch 1 according to this embodiment, the position of the gap waveguide 131 of the gap waveguide 130 connecting the first waveguide 121 and the third waveguide 141 is fixed, and therefore, unlike the conventional sliding waveguide switch, unintended reflection points caused by misalignment between the waveguides do not occur. This allows the waveguide switch 1 according to this embodiment to function as a waveguide switch with excellent broadband performance.

[0090] Second embodiment Next, a waveguide connection structure used in a waveguide switch according to a second embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the first embodiment are denoted by the same reference numerals and will not be described as necessary.

[0091] 13 is a partial perspective view showing the configuration of multiple elliptical choke grooves 22 provided in the third end face 20a of the first fixing block 20 in the waveguide connection structure according to this embodiment. In the third end face 20a of the fixing block 20, the choke grooves 22 are arranged in parallel at predetermined equal intervals t3 on the outside of the choke groove 22-1 with reference to the opening of the first waveguide 121. The depth D of each of the choke grooves 22-1, 22-2, 22-3, 22-4, 22-5 is set to a value equal to the in-guide wavelength λ corresponding to the target frequency for leakage prevention. g It is 1 / 4 of that.

[0092] Specifically, the choke groove 22 has a configuration in which four choke grooves 22-2, 22-3, 22-4, and 22-5 are provided in order from the inside to the outside of the choke groove 22-1, which is the same as the elliptical choke groove 22 of the first embodiment. A partition wall portion 24-1 is provided between the waveguide forming groove 21 and the choke groove 22-1, a partition wall portion 24-2 is provided between the choke grooves 22-1 and 22-2, a partition wall portion 24-3 is provided between the choke grooves 22-2 and 22-3, a partition wall portion 24-4 is provided between the choke grooves 22-3 and 22-4, and a partition wall portion 24-5 is provided between the choke grooves 22-4 and 22-5. The partition wall portions 24-2, 24-3, 24-4, and 24-5 have the same thickness.

[0093] The partition wall 24-1 separating the waveguide groove 21 and the choke groove 22-1 is the same as that in the first embodiment, and as shown in Fig. 4, the inner peripheral side wall surface 22a is provided with groove protrusions 23, 23 corresponding to the corners 21c of the waveguide groove 21. The width w3 of both of the groove protrusions 23, 23 is 1 / 2 the wavelength λ in the guide corresponding to the target frequency for leakage prevention. g It is 1 / 4 of that.

[0094] FIG. 14 is a diagram showing a simulation model. In the choke groove 22 according to this embodiment, the boundary of the choke groove 22-1 is defined by the inner ellipse e1-1 and the outer ellipse e2-1 in plan view, the boundary of the choke groove 22-2 is defined by the inner ellipse e1-2 and the outer ellipse e2-2, the boundary of the choke groove 22-3 is defined by the inner ellipse e1-3 and the outer ellipse e2-3, the boundary of the choke groove 22-4 is defined by the inner ellipse e1-4 and the outer ellipse e2-4, and the boundary of the choke groove 22-5 is defined by the inner ellipse e1-5 and the outer ellipse e2-5, similar to the inner ellipse e1 and the outer ellipse e2-1 that define the planar shape of the choke groove 22 in FIG. 4. The center of each of the inner ellipse and the outer ellipse coincides with the center O of the rectangular opening of the first waveguide 121. Therefore, the ellipticity of each of the inner ellipse and the outer ellipse approaches 1 from the innermost inner ellipse to the outermost outer ellipse.

[0095] In the simulation model shown in FIG. 14, the dimensions of the multiple elliptical choke groove 22 are as follows (see also FIG. 4): The metal pin 15 had the same dimensions as in the model described in FIG. Choke groove width (w2): 0.3617mm Choke groove spacing (t3): 0.12mm Width of groove protrusion 23 (w3): ​​0.312 mm Choke groove depth (D): 0.286mm Gap (G) between the third end surface 20a and the fifth end surface 30a: 0.05 mm

[0096] FIG. 15 shows the reflection characteristic S between the first waveguide 121 and the gap waveguide 131 in the waveguide connection structure 100, which was calculated using the simulation model of FIG. 11 , transmission characteristic S 21The figures show the results of simulations for the number of grooves and the leakage rate. Although the band itself does not change much due to multiplexing, a tendency for the drop to become sharper was observed (see Figs. 15(a) and (b)). Furthermore, when the leakage rate was calculated, it was confirmed that, despite the standard gap G between the first waveguide 120 and the gap waveguide 130 being set at 50 μm, the five-layer structure can achieve a leakage rate of less than -50 dB over the entire band of WR-3 (see Fig. 15(c)).

[0097] In the above description, the third end face 20a of the first fixing block 20 in the waveguide connection structure 100 includes five choke grooves 22, but the present invention is not limited to this and may include six or more or four or less elliptical choke grooves.

[0098] As described above, in the waveguide connection structure 100 according to this embodiment, the third end face 20a of the first fixed block 20 has multiple partially elliptical choke grooves surrounding the opening of the first waveguide 121 from the upper face 10a of the base block 10 upward. This configuration can effectively suppress leakage of electromagnetic waves from the connection point between the standard first waveguide 120 and the gap waveguide 130. This is because the choke groove 22 has a structure that follows the change in the equiphase surface of the electromagnetic waves leaking into the gap G in the gap side region (upper region) shown in FIG. 10(b). As a result, the waveguide connection structure 100 according to this embodiment can suppress leakage of electromagnetic waves from the gap G at the connection point between the first waveguide 120 and the gap waveguide 130 more effectively than the waveguide connection structure of the first embodiment.

[0099] Generally, a gap is always necessary in a movable part such as a waveguide switch, but there is a lower limit to the gap allowed due to restrictions on machining accuracy. The gap may also widen due to wear of the sliding parts of the mechanism supporting the movable part. The higher the frequency (shorter the wavelength), the wider the gap becomes relative to the wavelength even for the same gap, and the greater the leakage of electromagnetic waves. Therefore, the waveguide connection structure 100 and the waveguide switch 1 according to the present invention are particularly useful for preventing leakage in the high frequency band, and since the gap allowed for the movable part can be made wider, the machining accuracy is relaxed and resistance to aging is also increased. [Industrial Applicability]

[0100] As described above, the present invention has the effect of being able to effectively suppress leakage of electromagnetic waves from the gap at the connection point between the standard input / output waveguides and the gap waveguide of the movable part, and has excellent broadband performance, and is useful for the entire waveguide connection structure and the waveguide switch using the same. [Explanation of symbols]

[0101] 1 Waveguide Switch 10 Base Block 10a top surface 10b 1st end surface 10c 2nd end face 11 Area 1 12 Area 2 13 Third Area 14 Bottom groove 14a First Lower Groove 14b 2nd bottom groove 14c 3rd bottom groove 15 Metal Pin 15a Top side 16 Convex part 16a Top side 17 Storage area (bottom of hangar) 20 First Fixed Block (Fixed Block) 20a 3rd end face 20b 4th end face 20c,30c,40c bottom surface 21 Waveguide forming groove (first waveguide forming groove) 21a Side wall 21b Bottom wall surface 21c Corner 22,22-1,22-2,22-3,22-4,22-5 Choke groove 22a Inner side wall surface 23 Groove inner protrusion 24,24-1,24-2,24-3,24-4,24-5 Bulkhead part 24a End face 30 Movable Block 30a 5th end face 30b 6th end face 31 Protrusion 31a Top surface 40 Second Fixed Block 40a 7th end face 40b 8th end face 41 Waveguide forming groove (second waveguide forming groove) 58 Storage Area 60 Drive unit 70 Waveguide 80 Gap Waveguide 100 Waveguide connection structure 120 First Waveguide 121 First Waveguide 130 Second Waveguide (Gap Waveguide) 131 Second Waveguide (Gap Waveguide) 140 3rd Waveguide 141 Third Waveguide

Claims

1. A waveguide connection structure (100) between a first waveguide (120) and a second waveguide (130), a base block (10) having a lower groove (14) formed on an upper surface (10a) from a first end surface (10b) to a second end surface (10c) opposite the first end surface, the lower groove including a first lower groove (14a) and a second lower groove (14b) connected to each other in a groove longitudinal direction, and a plurality of metal pins (15) periodically arranged on both sides of the second lower groove on both sides of the second lower groove on the upper surface; a fixed block (20) having a lower surface (20c) provided with a waveguide forming groove (21) extending from a third end surface (20a) to a fourth end surface (20b) opposite the third end surface, the fixed block (20) being disposed on the upper surface such that the waveguide forming groove faces the first lower groove of the base block, thereby forming the first waveguide having a first waveguide (121); a movable block (30) having a fifth end surface (30a) facing the third end surface of the fixed block, and a lower surface (30c) spaced apart from upper surfaces of the metal pins of the base block and covering the metal pins and the second lower groove, and forming the second waveguide having a second waveguide (131) on the second lower groove; The third end surface (30a) of the fixed block and the fifth end surface (30a) of the movable block are arranged in parallel to face each other with a predetermined gap (G) therebetween, a partially elliptical choke groove (22) surrounding an opening of the first waveguide from the top surface of the base block upward is formed on the third end face of the fixed block.

2. 2. The waveguide connection structure according to claim 1, wherein an inner groove protrusion (23) protruding into the choke groove is formed on an inner peripheral side wall surface of the choke groove in correspondence with a corner (21 c) of an end opening formed by a bottom wall surface and a side wall surface of the waveguide forming groove.

3. 3. The waveguide connection structure according to claim 2, wherein the choke groove has a depth (D) equivalent to 1 / 4 of a guide wavelength corresponding to a frequency to be prevented from leaking.

4. 4. The waveguide connection structure according to claim 3, wherein a distance (t1) between an end opening of the waveguide formation groove and the choke groove is set to ¼ of the in-guide wavelength corresponding to the target frequency for leakage prevention in at least a minor axis direction of an ellipse (e1, e2) that is centered at a center of the opening of the first waveguide, has a major axis direction parallel to a long side of the opening, and defines a planar shape of the choke groove.

5. 2. The waveguide connection structure according to claim 1, wherein a plurality of grooves (22-1, ..., 22-5) having the same width are arranged in parallel at equal intervals on the outside of the choke groove with respect to the opening of the first waveguide on the third end face of the fixed block.

6. A waveguide connection structure (100) between a first waveguide (120), a second waveguide (130), and a third waveguide (140), comprising: a base block (10) having a lower groove (14) formed in an upper surface (10a) from a first end surface (10b) to a second end surface (10c) opposite the first end surface, the lower groove including a first lower groove (14a), a second lower groove (14b), and a third lower groove (14c) connected in sequence in the groove longitudinal direction, and a plurality of metal pins (15) periodically arranged on both sides of the second lower groove on either side of the second lower groove on the upper surface; a first fixed block (20) having a first waveguide forming groove (21) formed in a lower surface (20c) from a third end surface (20a) to a fourth end surface (20b) opposite the third end surface, and disposed on the upper surface such that the first waveguide forming groove faces the first lower groove of the base block, to form the first waveguide having a first waveguide (121); a movable block (30) having a lower surface (30c) spaced apart from upper surfaces of the plurality of metal pins of the base block and covering the plurality of metal pins and the second lower groove, and forming the second waveguide having a second waveguide (131) on the second lower groove; a second fixed block (40) having a second waveguide forming groove (41) formed in a lower surface (40c) from a seventh end surface (40a) to an eighth end surface (40b) opposite the seventh end surface, and disposed on the upper surface such that the second waveguide forming groove faces the third lower groove of the base block, to form the third waveguide having a third waveguide (141); the movable block has a fifth end surface (30a) arranged in parallel to face the third end surface of the first fixed block with a predetermined gap (G) therebetween, and a sixth end surface (30b) arranged in parallel to face the seventh end surface of the second fixed block with a predetermined gap (G) therebetween, the waveguide connection structure, in which a partially elliptical choke groove (22) is formed in at least one of the third end face of the first fixing block and the seventh end face of the second fixing block, surrounding an opening of the first waveguide or the third waveguide from the top face of the base block upward; A drive device (60) for sliding the movable block; Equipped with A protrusion (31) having a size capable of moving between the rows of the plurality of metal pins is provided on the lower surface (30c) of the movable block, The driving device slides the movable block so that the movable block can be switched between an ON state in which the protrusion of the movable block is located in a storage area outside the multiple metal pins with respect to the second waveguide, and an OFF state in which the protrusion of the movable block is located within the second waveguide.

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