Circularly-polarized-wave converter

Abstract

To easily install a dielectric plate into an internal part of a circular wave guide pipe while avoiding deterioration of a characteristic of a circularly-polarized conversion.SOLUTION: A circularly-polarized-wave converter 30 comprises: a dielectric plate 31 that has a flat surface part 312 and projection parts 311 toward a direction along the flat surface part 312; and a pair of circular wave guide pipes 32-1 and 32-2 that serve as a cylinder body and can be bonded so that a cross section 320 in each open part is contacted. In the pair of circular wave guide pipes 32-1 and 32-2, grooves 321 are formed in a long direction in the vicinity of the cross rection 320 in an inner wall, respectively. The pair of circular wave guide pipes 32-1 and 32-2 are bonded so that the grooves 321 are communicated with each other. The dielectric plate 31 is installed in spaces inside the pair of circular wave guide pipes 32-1 and 32-2 in a state where the projection parts 311 are fitted to the grooves 321 in the pair of circular wave guide pipes 32-1 and 32-2.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a circular polarization converter. [Background technology]

[0002] In satellite communications and other applications, circular polarization is often used instead of linear polarization because satellites rotate and the polarization plane cannot be fixed. A circular polarization converter is a device that converts linear polarization into circular polarization, and a configuration that includes an element for phase shift inside the waveguide is widely used. In order to transmit circular polarization, a circular waveguide is required instead of a rectangular waveguide. In this structure, circular polarization is obtained by giving a phase difference of 90 degrees in a direction tilted 45 degrees to the polarization plane of the incident linear polarization.

[0003] One of the simplest methods for generating circularly polarized waves is to insert a dielectric plate that controls the circular polarization conversion into a circular waveguide. This method involves inserting a dielectric plate into the circular waveguide at an angle of 45 degrees to the polarization plane of the linearly polarized wave. In this method, it is essential to fix the dielectric plate inside the circular waveguide so that it maintains a 45-degree angle with respect to the polarization plane.

[0004] In relation to the technique for fixing a dielectric plate in a circular waveguide as described above, Patent Document 1 discloses a structure including a circular waveguide made of a resin material as a hollow cylinder having two opposing guide grooves formed in its inner wall surface in the longitudinal direction from one end opening. This structure includes a dielectric plate inserted into the circular waveguide along the guide grooves, and a fixing means for fixing the dielectric plate at a predetermined position in the guide grooves. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-347801 A Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of Patent Document 1 described above has an advantage in that the dielectric plate can be easily fixed inside the circular waveguide with a small number of parts. However, this technology requires the circular waveguide to have a guide groove for sliding the dielectric plate into the circular waveguide, and the length of the groove is equal to or greater than the width of the dielectric plate in the insertion direction. In this case, there is a concern that the circular polarization conversion characteristics may be significantly deteriorated by forming a long groove in the circular waveguide.

[0007] A primary object of the present invention is to make it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the characteristics of the circular polarization conversion. [Means for solving the problem]

[0008] A circular polarization converter according to one embodiment of the present invention comprises a dielectric plate having a planar portion and a protrusion in a direction along the planar portion, and a pair of cylindrical circular waveguides that can be joined by abutting their cross sections at their openings, each of the pair of circular waveguides having a groove formed in the longitudinal direction near the cross section in the inner wall, the pair of circular waveguides being joined to each other so that the grooves are continuous, and the dielectric plate is placed in the internal space of the pair of circular waveguides with the protrusion fitted into the grooves of the pair of circular waveguides. Effect of the Invention

[0009] The present invention makes it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the characteristics of the circular polarization conversion. [Brief description of the drawings]

[0010] [Figure 1] 1 is an external view of a circular polarization converter 10 according to the present disclosure. [Diagram 2] 1 is an external view of a dielectric plate 11 included in a circular polarization converter 10 according to the present disclosure. [Diagram 3]1 is an XY plan view of a circular polarization converter 10 in which a pair of circular waveguides 12 according to the present disclosure are joined at a cross section 120, as viewed in the negative direction of the Z axis. [Figure 4] 1A and 1B are YZ plan views of a circular polarization converter 10A before and after the dielectric plate 11 according to the present disclosure is installed, as viewed in the negative direction of the X axis. [Diagram 5] 1A and 1B are an XY plan view and an XZ plan view, respectively, of a circular polarization converter 10B in which a pair of circular waveguides 12B according to the present disclosure are joined at a cross section 120, viewed in the negative direction of the Z axis, and a positive direction of the Y axis. [Figure 6] 1A is a YZ plan view of a circular waveguide 22 of a circular polarization converter 20 according to the present disclosure as viewed in the negative direction of the X-axis, and a YX plan view of a dielectric plate 21 as viewed in the negative direction of the Z-axis. [Figure 7] 1 is an external view of a circular polarization converter 30 according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0012] <First embodiment> Fig. 1 is an external view of a circular polarization converter 10 according to the present disclosure. The circular polarization converter 10 is a device that converts linearly polarized waves into circularly polarized waves. In this disclosure, for convenience of explanation, each drawing will show an X-axis, a Y-axis, and a Z-axis in a three-dimensional space, and the coordinate system will be common between the drawings. Also, in Fig. 1, for convenience of explanation, a part of the configuration is shown in a see-through manner.

[0013] The circular polarization converter 10 comprises a dielectric plate 11 and a pair of circular waveguides 12-1 and 12-2.

[0014] The dielectric plate 11 includes two protrusions 111 (convex portions) that are, for example, rectangular parallelepipeds, and a flat portion 112 that is, for example, rectangular parallelepipeds. The protrusions 111 and the flat portion 112 are formed in a direction along a plane that is parallel (including approximately parallel) to the XY plane. The shapes of the protrusions 111 and the flat portion 112 are not limited to rectangular parallelepipeds, and may be shapes different from rectangular parallelepipeds. In addition, the number of protrusions 111 included in the dielectric plate 11 is not limited to two, but in order for the dielectric plate 11 to be stably installed inside the circular waveguides 12-1 and 12-2, it is desirable that the number of protrusions 111 be two or more.

[0015] The circular waveguide 12-1 has a groove 121-1 (recess) formed in the longitudinal direction (X-axis direction) on its inner wall surface near its cross section 120-1, and the circular waveguide 12-2 has a groove 121-2 (recess) formed in the longitudinal direction (X-axis direction) on its inner wall surface near its cross section 120-2. Note that in the present disclosure, at least one of the circular waveguides 12-1 and 12-2, or these two together, may be referred to as the circular waveguide 12, at least one of the cross sections 120-1 and 120-2, or these two together, may be referred to as the cross section 120, and at least one of the grooves 121-1 and 121-2, or these two together, may be referred to as the groove 121.

[0016] The circular waveguides 12-1 and 12-2 are cylindrical bodies, and are joined together by abutting the cross sections 120-1 and 120-2 at the openings of each other. The circular waveguides 12-1 and 12-2 are joined together so that the grooves 121-1 and 121-2 are continuous at the cross sections 120-1 and 120-2. The circular waveguides 12-1 and 12-2 may have, for example, a mechanism for screwing the circular waveguides 12-1 and 12-2 together in the vicinity of the cross sections 120-1 and 120-2. Alternatively, the circular waveguides 12-1 and 12-2 may be joined together at the cross section 120 by an adhesive or the like. However, it is preferable that the adhesive is made of a material (substance) whose effect on the characteristics of the circular polarization conversion is negligible. Further, cross section 120 is formed parallel (including approximately parallel) to the YZ plane so as to be perpendicular (including approximately perpendicular) to the propagation direction of the radio waves (the positive direction of the X-axis) that are the subject of circular polarization conversion in circular waveguide 12, and its shape is circular.

[0017] The dielectric plate 11 is placed in the internal space of the circular waveguide 12 with the protrusion 111 fitted into the groove 121 in the pair of circular waveguides 12 joined together such that the grooves 121-1 and 121-2 join in the cross section 120.

[0018] In order for the dielectric plate 11 to be firmly fixed inside the circular waveguide 12, it is desirable that the groove 121 and the protrusion 111, which are fitted in the state where the circular waveguides 12-1 and 12-2 are joined, have approximately the same shape and size. That is, the size of the groove 121 is slightly larger than the size of the protrusion 111, and the difference in size is equal to or less than a threshold. The groove 121 formed in the state where the circular waveguide 12 is joined is formed to have a size that satisfies that the degree of deterioration of the circular polarization conversion characteristics caused by the groove 121 is equal to or less than a predetermined standard. The degree of deterioration of the circular polarization conversion characteristics caused by the groove 121 can be calculated from a predetermined calculation formula that calculates the degree of deterioration of the circular polarization conversion characteristics from the shape of the circular waveguide 12 including the size of the groove 121.

[0019] Fig. 2 is an external view of a dielectric plate 11 included in the circular polarization converter 10 according to the present disclosure. Fig. 3 is an XY plan view of the circular polarization converter 10 in which a pair of circular waveguides 12 according to the present disclosure are joined at a cross section 120, as viewed in the negative direction of the Z axis.

[0020] In the case where the protrusions 111 and the flat portion 112 of the dielectric plate 11 are uniformly formed of a dielectric, the width of the dielectric included in the dielectric plate 11 in the Y-axis direction shown in FIGS. 2 and 3 will be different between the portion where the protrusions 111 are formed and the portion where they are not formed. In this case, the characteristics of the circular polarization conversion will deteriorate due to the occurrence of an impedance mismatch. Therefore, it is desirable that the protrusions 111 are formed of a material different from that of the flat portion 112, for example, of a metal, and that the potential of the protrusions 111 is set to the ground level. In this case, the width of the dielectric included in the dielectric plate 11 in the Y-axis direction shown in FIGS. 2 and 3 will be the same between the portion where the protrusions 111 are formed and the portion where they are not formed (i.e., the width of the flat portion 112 in the Y-axis direction), so that the deterioration of the characteristics of the circular polarization conversion due to the impedance mismatch described above can be avoided.

[0021] Furthermore, as the dielectric plate 11 according to the present disclosure, for example, a printed circuit board or a ceramic substrate such as LTCC (Low Temperature Co-fired Ceramics) or HTCC (High Temperature Co-fired Ceramics) can be used. When a printed circuit board or a ceramic substrate is used as the dielectric plate 11, as exemplified in Figures 2 and 3, a through hole 113 is formed in the Z-axis direction in the protruding portion 111, and the potential of the protruding portion 111 is set to the ground level, thereby making it possible to avoid the deterioration of the circular polarization conversion characteristics due to the impedance mismatch described above.

[0022] The circular polarization converter 10 according to the present disclosure makes it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the characteristics of the circular polarization conversion. The reason is that in the circular polarization converter 10, the dielectric plate 11 is installed in the internal space of the circular waveguide 12 with its protrusion 111 fitted into a groove 121 formed in the vicinity of the cross section 120 of a pair of the circular waveguides 12.

[0023] The effects achieved by the circular polarization converter 10 according to the present disclosure will be described in detail below.

[0024] For example, in order to easily fix the dielectric plate inside the circular waveguide with a small number of parts, there is a circular polarization converter in which a guide groove is formed in the circular waveguide for sliding and inserting the dielectric plate into the circular waveguide. In such a circular polarization converter, the length of the guide groove is equal to or greater than the width of the dielectric plate in the insertion direction, and the formation of a long groove in the circular waveguide causes a problem of significant degradation of the circular polarization conversion characteristics.

[0025] In response to such problems, the circular polarization converter 10 according to the present disclosure includes a dielectric plate 11 having a planar portion 112 and a protrusion 111 in a direction along the planar portion 112, and a pair of cylindrical circular waveguides 12 that can be joined by abutting cross sections 120 at the openings of the pair. A groove 121 is formed in the longitudinal direction of each of the pair of circular waveguides 12 near the cross section 120 on the inner wall. The pair of circular waveguides 12 are joined to each other so that the grooves 121 of each of the pair of circular waveguides 12 are continuous. The dielectric plate 11 is placed in the space inside the pair of circular waveguides 12 with the protrusion 111 fitted into the groove 121 of the pair of circular waveguides 12. That is, in the circular polarization converter 10, the length of the groove 121 formed in the circular waveguide 12 is only required to be approximately the width of the protrusion 111 in the insertion direction of the dielectric plate 11, and therefore deterioration of the characteristics of the circular polarization conversion can be avoided.

[0026] Furthermore, in the circular polarization converter 10 according to the present disclosure, the groove 121 formed when the pair of circular waveguides 12 are joined is formed to a size that satisfies the degree of deterioration of the circular polarization conversion characteristics caused by the groove 121 being equal to or less than a standard. This allows the circular polarization converter 10 to reliably avoid deterioration of the circular polarization conversion characteristics.

[0027] Furthermore, in the circular polarization converter 10 according to the present disclosure, the protrusion 111 and the flat portion 112, which is the dielectric plate 11 excluding the protrusion 111, are made of different materials, for example, the protrusion 111 is made of a metal. This makes it possible for the circular polarization converter 10 to avoid deterioration of the circular polarization conversion characteristics due to impedance mismatch that occurs when the protrusion 111 is made of a dielectric material like the flat portion 112, by setting the potential of the protrusion 111 to the ground level.

[0028] Furthermore, in the circular polarization converter 10 according to the present disclosure, the dielectric plate 11 is formed of a printed circuit board or a ceramic board, and a through hole 113 is formed in the protrusion 111. This allows the circular polarization converter 10 to easily avoid deterioration of the circular polarization conversion characteristics due to impedance mismatch by setting the potential of the protrusion 111 in which the through hole 113 is formed to the ground level.

[0029] Furthermore, in the circular polarization converter 10 according to the present disclosure, the cross section 120 is formed (parallel to the YZ plane) so as to be perpendicular (including approximately perpendicular) to the traveling direction of the radio wave in the circular waveguide 12 (positive direction of the X-axis), but the direction in which the cross section 120 is formed may be different from this. For example, the cross section 120 may be formed so as to be parallel (including approximately parallel) to the XY plane. In this case, it is expected that the degree of deterioration of the characteristics of the circular polarization conversion will increase due to the wider cross-sectional area of ​​the cross section 120 compared to the case in which the cross section 120 is formed so as to be parallel to the above-mentioned YZ plane, but it is also possible to form the cross section 120 so as to be parallel to the XY plane as long as the degree of deterioration of the characteristics is within a standard range.

[0030] <First Modification of the First Embodiment> FIG. 4 is a YZ plan view of the circular polarization converter 10A before and after the dielectric plate 11 according to the present disclosure is installed, as viewed in the negative direction of the X axis.

[0031] Circular polarization converter 10A includes dielectric plate 11, a pair of circular waveguides 12A, and a protection section 13. Note that components having the same functions as those in the above-described circular polarization converter 10 are given the same reference numbers as those in the circular polarization converter 10, and detailed descriptions thereof will be omitted.

[0032] Protective parts 13 are attached to the two protruding parts 111 of the dielectric plate 11 to protect the protruding parts 111 from damage. In the example shown in Fig. 4, the shape of the tip part of the protective part 13 in the YZ plane view is a sector shape, but the shape of the protective part 13 may be different from the shape exemplified in Fig. 4.

[0033] A groove 121A having the same shape as protective portion 13 is formed on the inner wall surface of the pair of circular waveguides 12A near cross section 120A. Then, dielectric plate 11 with protective portion 13 attached to protrusion 111 is placed in the internal space of circular waveguide 12A with protective portion 13 fitted into groove 121A in the pair of circular waveguides 12A joined together such that groove 121A joins together at cross section 120A.

[0034] The circular polarization converter 10A according to the present disclosure makes it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the circular polarization conversion characteristics, for the reasons described above in relation to the first embodiment.

[0035] Moreover, the circular polarization converter 10A according to the present disclosure further includes a protective portion 13 that can be attached to the protrusion 111. In the circular polarization converter 10A, the protective portion 13 and the groove 121A are formed into shapes that allow them to fit into each other. In the circular polarization converter 10A, the dielectric plate 11 is placed in the space inside the pair of circular waveguides 12A with the protective portion 13 attached to the protrusion 111 fitted into the groove 121A. This makes it possible to prevent the protrusion 111 from being damaged when the dielectric plate 11 is placed inside the circular waveguide 12A, thereby improving the reliability of the circular polarization converter 10A.

[0036] <Second Modification of the First Embodiment> 5 is an XY plan view, seen in the negative direction of the Z axis, and an XZ plan view, seen in the positive direction of the Y axis, of a circular polarization converter 10B in which a pair of circular waveguides 12B according to the present disclosure are joined at a cross section 120B. Note that components having the same functions as those in the above-mentioned circular polarization converter 10 are given the same numbers as those in the circular polarization converter 10, and detailed descriptions thereof will be omitted.

[0037] The pair of circular waveguides 12B-1 and 12B-2 are formed with guide grooves 122 for the protective portion 13B, which will be described later, to slide in the X-axis direction and fit into. The length of the guide grooves 122 in the X-axis direction of each of the circular waveguides 12B-1 and 12B-2 is preferably, for example, about half the length of the protective portion 13B in the X-axis direction. In this case, by inserting half of the protective portion 13B into each of the circular waveguides 12B-1 and 12B-2, not only the fixing of the dielectric plate 11 by the protective portion 13B but also the fixing of the two circular waveguides 12B-1 and 12B-2 can be realized at the same time. Furthermore, the above-mentioned structure prevents the circular waveguide 12B from shifting laterally and can be fixed more firmly, so that the deterioration of the circular polarization conversion characteristics can be more reliably suppressed. 5, the length in the X-axis direction of the guide groove 122 and the protective portion 13B is equal to the length in the X-axis direction of the dielectric plate 11, but the length in the X-axis direction of the guide groove 122 and the protective portion 13B may be different from the length in the X-axis direction of the dielectric plate 11. A protective portion groove 121B is formed in the protective portion 13B, and the protrusion portion 111 of the dielectric plate 11 fits into the protective portion groove 121B. The cross-sectional shape of the tip portion of the guide groove 122 and the protective portion 13B in the YZ plane may be, for example, a sector shape similar to that of the groove 121A and the protective portion 13 illustrated in FIG. 4, or may be a different shape.

[0038] The dielectric plate 11 with the protective portion 13B attached by fitting the protrusion 111 into the groove 121B of the protective portion is inserted into the inside of the circular waveguide 12B by the protective portion 13B sliding in the X-axis direction and fitting into the guide groove 122. The pair of circular waveguides 12B-1 and 12B-2 are then joined to each other at the cross section 120B, and the dielectric plate 11 with the two protective portions 13B attached and inserted into the inside of the circular waveguide 12B as described above is placed in the space inside the circular waveguide 12B.

[0039] The circular polarization converter 10B according to the present disclosure makes it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the circular polarization conversion characteristics, for the reasons described above in relation to the first embodiment.

[0040] In addition, in the circular polarization converter 10B according to the present disclosure, the circular waveguide 12B is formed with a guide groove 122 into which the protective portion 13B slides in the X-axis direction and fits. In order to avoid deterioration of the characteristics of the circular polarization conversion, it is preferable that the circular waveguide 12B and the protective portion 13B are made of the same material. In that case, in the example shown in FIG. 5, the circular waveguide 12B is formed with a groove-formed portion including the protective portion groove 121B (the protective portion 13B fitted into the guide groove 122) and a portion other than the groove-formed portion as separate bodies, and the groove-formed portion can be considered to be attached to the portion other than the groove-formed portion. In this way, the circular polarization converter 10B has a structure in which the two protective portions 13B are slidably inserted into the circular waveguide 12B in a state where they are attached to the protrusions 111 of the dielectric plate 11. In this case, for example, the state of engagement between the protrusion 111 and the groove 121B of the protective part can be adjusted before the protective part 13B with the dielectric plate 11 attached is inserted into the circular waveguide 12B via the guide groove 122. Then, the protective part 13B functions as a part for fixing the dielectric plate 11 inside the circular waveguide 12B. This enables the circular polarization converter 10B to more firmly fix the dielectric plate 11 at a predetermined position inside the circular waveguide 12B.

[0041] <Second embodiment> 6 is a YZ plan view of the circular waveguide 22 of the circular polarization converter 20 according to the present disclosure viewed in the negative direction of the X axis, and a YX plan view of the dielectric plate 21 of the circular polarization converter 20 viewed in the negative direction of the Z axis. The circular polarization converter 20 is an application of array antenna technology, in which multiple antennas are evenly arranged to operate as a single antenna, to the circular polarization converter.

[0042] The circular polarization converter 20 includes a plurality of dielectric plates 21 and a plurality of circular waveguides 22. The plurality of circular waveguides 22 are divided into one group and another group (not shown) of the same number as the one group. The plurality of circular waveguides 22 are arranged parallel to and close to each other in the longitudinal direction (X-axis direction) so that each cross section 220 in the one group is included in a predetermined plane parallel to (including approximately parallel to) the YZ plane.

[0043] A notch 221 extending from the opening in the longitudinal direction (X-axis direction) is formed in each of the circular waveguides 22. Adjacent circular waveguides 22 in the circular polarization converter 20 are connected to each other via a connection portion 222 formed to include the notch 221.

[0044] In addition, although FIG. 6 shows one row each of the multiple dielectric plates 21 and the multiple circular waveguides 22, the circular polarization converter 20 may have a configuration in which the multiple dielectric plates 21 and the multiple circular waveguides 22 are each arranged in multiple rows (i.e., in an array).

[0045] The dielectric plate 21 has two protrusions 211 and a flat portion 212, similar to the dielectric plate 11 of the circular polarization converter 10. The multiple dielectric plates 21 are arranged such that the individual protrusions 211 are aligned on a straight line parallel (including approximately parallel) to the Y axis. The individual protrusions 211 of adjacent dielectric plates 21 are connected to each other. Then, each of the multiple dielectric plates 21 is inserted collectively into the circular waveguide 22 in the X-axis direction with the protrusions 211 fitted into the notches 221 formed in the circular waveguides 22 of one group and the notches 221 formed in the circular waveguides 22 of the other group, and is placed in the space inside each circular waveguide 22.

[0046] The circular polarization converter 20 according to the present disclosure makes it possible to easily install a dielectric plate inside a circular waveguide while avoiding deterioration of the characteristics of the circular polarization conversion, for the reasons described above in relation to the first embodiment.

[0047] The circular polarization converter 20 according to the present disclosure includes a plurality of dielectric plates 21 and a plurality of circular waveguides 22, and the plurality of circular waveguides 22 are divided into one group and another group having the same number as the one group. The plurality of circular waveguides 22 are arranged in parallel and close to each other in the longitudinal direction so that each cross section 220 in the one group is included in a predetermined plane. The plurality of dielectric plates 21 are each connected to each other at their respective protrusions 211 so as to form a straight line, and the circular waveguides 22 are each formed with a cut 221 oriented in the longitudinal direction from the opening instead of a groove. Each of the plurality of dielectric plates 21 is installed in the internal space of each of the circular waveguides 22 with the protrusion 211 fitted into the cut 221 formed in the circular waveguides 22 of the one group and the cut 221 formed in the circular waveguides 22 of the other group. As a result, in the circular polarization converter 20, a plurality of dielectric plates 21 can be placed in the internal space of the circular waveguide 22 all at once, so that the production cost of the circular polarization converter 20 can be reduced.

[0048] <Third embodiment> FIG. 7 is an external view of a circular polarization converter 30 according to the present disclosure.

[0049] The circular polarization converter 30 according to the present disclosure comprises a dielectric plate 31 having a planar portion 312 and a protrusion portion 311 in a direction along the planar portion 312, and a pair of cylindrical circular waveguides 32-1 and 32-2 which can be joined by abutting cross sections 320 at each opening.

[0050] The pair of circular waveguides 32-1 and 32-2 each have a groove 321 formed in the longitudinal direction near a cross section 320 on the inner wall. The pair of circular waveguides 32-1 and 32-2 are joined to each other so that the grooves 321 are continuous. The groove 321 has a structure similar to that of the groove 121 in the circular polarization converter 10, for example. The pair of circular waveguides 32-1 and 32-2 each have a structure similar to that of the circular waveguides 12-2 and 12-2 in the circular polarization converter 10, for example.

[0051] The dielectric plate 31 is placed in the space inside the pair of circular waveguides 32-1 and 32-2 with the protrusions 311 fitted into the grooves 321 in the pair of circular waveguides 32-1 and 32-2. The protrusions 311 have a structure similar to that of the protrusions 111 in the circular polarization converter 10, for example. The dielectric plate 31 has a structure similar to that of the dielectric plate 11 in the circular polarization converter 10, for example.

[0052] The circular polarization converter 30 according to the present disclosure makes it possible to easily install the dielectric plate inside the circular waveguide while avoiding deterioration of the characteristics of the circular polarization conversion. The reason is that in the circular polarization converter 30, the dielectric plate 31 is installed in the space inside the circular waveguides 32-1 and 32-2 with the protrusions 311 thereof fitted into the grooves 321 formed in the vicinity of the cross sections 120 of the pair of circular waveguides 32-1 and 32-2.

[0053] The present invention has been described above by taking the above-mentioned embodiment as an exemplary example. However, the present invention is not limited to the above-mentioned embodiment. That is, the present invention can be applied in various aspects that can be understood by a person skilled in the art within the scope of the present invention. [Explanation of symbols]

[0054] 10 Circular polarization converter 10A Circular Polarization Converter 10B Circular polarization converter 11 Dielectric plate 111 Protrusion 112 Plane section 113 Through Hole 12 Circular Waveguide 12A Circular Waveguide 12B Circular Waveguide 120 Section 120A cross section 120B cross section 121 Groove 121A Groove 121B Groove of protective part 122 Guide groove 13 Protection part 13B Protective part 20 Circular polarization converter 21 Dielectric plate 211 Protrusion 212 Plane section 22 Circular Waveguide 220 Section 221 Cut 222 Connection 30 Circular polarization converter 31 Dielectric plate 311 Protrusion 312 Plane section 32-1 and 32-2 Circular Waveguides 320 Section 321 Groove

Claims

1. a dielectric plate having a flat portion and a protrusion extending along the flat portion; a pair of cylindrical circular waveguides that are joinable by abutting each other at cross sections at their openings; Equipped with A groove is formed in each of the pair of circular waveguides in the longitudinal direction near the cross section on the inner wall, The pair of circular waveguides are joined to each other so that the grooves of each of the circular waveguides are continuous with each other, the dielectric plate is placed in an internal space of the pair of the circular waveguides with the protrusions fitted into the grooves of the pair of the circular waveguides; Circular polarization converter.

2. the groove formed when the pair of circular waveguides are joined is formed to a size satisfying that a degree of deterioration of the characteristics of the circular polarization conversion caused by the groove is equal to or less than a standard.

2. The circular polarization converter according to claim 1.

3. the protrusion and the dielectric plate excluding the protrusion are formed of different materials.

3. The circular polarization converter according to claim 1 or 2.

4. the dielectric plate is formed of a printed circuit board or a ceramic board, A through hole is formed in the protrusion.

4. The circular polarization converter according to claim 3.

5. The protrusion is formed of a metal.

4. The circular polarization converter according to claim 3.

6. A plurality of the dielectric plates and a plurality of the circular waveguides are provided, the plurality of circular waveguides are divided into one group and another group having the same number as the one group; the plurality of circular waveguides in the one group are arranged parallel to each other in close proximity to each other in a longitudinal direction such that each of the cross sections is included in a predetermined plane; Each of the plurality of dielectric plates has the projections connected to each other so as to form a straight line, In the circular waveguide, cuts are formed in place of the grooves and extending in a longitudinal direction from the opening, each of the plurality of dielectric plates is disposed in an internal space of each of the circular waveguides with the protrusions fitted into the notches formed in the circular waveguides of the one group and the circular waveguides of the other group; 3. The circular polarization converter according to claim 1 or 2.

7. Further comprising a protective part that can be attached to the protrusion, The protective portion and the groove are formed into shapes that can be fitted into each other, the dielectric plate is installed in the space inside the pair of circular waveguides with the protective portion attached to the protrusion fitted into the groove; 3. The circular polarization converter according to claim 1 or 2.

8. a groove-forming portion including the groove and a portion other than the groove-forming portion of the circular waveguide are formed as separate bodies, and the groove-forming portion is attached to the portion other than the groove-forming portion; 3. The circular polarization converter according to claim 1 or 2.

9. The cross section is formed so as to be perpendicular to the propagation direction of the radio wave in the circular waveguide.

3. The circular polarization converter according to claim 1 or 2.

10. a difference in size between the groove and the protrusion formed when the pair of circular waveguides are joined is equal to or smaller than a threshold value; 3. The circular polarization converter according to claim 1 or 2.

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