Circular polarizer and its manufacturing method

Abstract

The circularly polarized wave generator comprises a hollow waveguide (10) having a first input / output terminal (11) at one end and a second input / output terminal (12) at the other end, the hollow portion having a circular cross section, and a pair of ridges (20), (30) each having a central axis parallel to the axis of the waveguide (10) and arranged opposite each other on the inner wall surface of the waveguide (10), the pair of ridges (20), (30) each having a first input / output terminal (21), (31) at one end and a second input / output terminal at the other end. (22), (32), and intermediate portions (23), (33) between the first input / output end portions (21), (31) and the second input / output end portions (22), (32), the intermediate portions (23), (33) being periodically provided in the tube axis direction of the waveguide (10), and each of the intermediate portions (23), (33) having a plurality of protrusions (23a1) to (23a2) protruding in a direction along a line perpendicular to a line connecting the central axes of the pair of ridges (20), (30) in a first plane perpendicular to the tube axis of the waveguide (10). N ), (33a1)~(33a N , and a plurality of protrusions (23a1) to (23a N ), (33a1)~(33a N The connecting portions (23b1) to (23b N-1 ), (33b1)~(33b N-1 )

Description

[Technical Field]

[0001] The present disclosure relates to a circular polarizer used primarily in the VHF band, UHF band, microwave band, and millimeter wave band, and a method for manufacturing the same. [Background technology]

[0002] Non-Patent Document 1 discloses a waveguide-based circular polarizer that, when a vertically linearly polarized signal or a horizontally linearly polarized signal is input, outputs a right-handed or left-handed circularly polarized signal depending on the input polarization signal. The circular polarizer shown in Non-Patent Document 1 has 14 corrugations and 5 matching steps in a square waveguide. The 14 corrugations formed within the waveguide are called ridges. The circular polarizer shown in Non-Patent Document 1 is manufactured by using wire discharge milling of an aluminum block. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Angel Mediavilla etal. “Quasi-Octave Bandwidth Phase Matched K / Ka Antenna Feed Subsystem for dual RHCP / LHCP Polarization,” pp719-722, 2012 EuMA. Summary of the Invention [Problem to be solved by the invention]

[0004] When the circular polarizer shown in Non-Patent Document 1 is connected to a horn antenna having a circular waveguide terminal, a converter from a square waveguide to a circular waveguide is required to connect to the horn antenna, which increases the number of components and the length in the tube axial direction.

[0005] The present disclosure has been made in consideration of the above points, and aims to provide a circular polarizer that has good reflection characteristics and axial ratio characteristics and does not increase in length in the tube axial direction even when connected to a horn antenna having a circular waveguide terminal. [Means for solving the problem]

[0006] The circular polarizer according to the present disclosure comprises a hollow waveguide having a hollow portion with a circular cross section, with one end serving as a first input / output terminal and the other end serving as a second input / output terminal, and a pair of ridges, each having a central axis parallel to the tube axis of the waveguide, and arranged opposite each other on the inner wall surface of the waveguide, each of the pair of ridges having a first input / output terminal at one end and a second input / output terminal at the other end, and an intermediate portion between the first input / output terminal and the second input / output terminal, the intermediate portions being periodically arranged in the tube axis direction of the waveguide, and each having a plurality of protrusions that protrude in a direction along a line perpendicular to a line connecting the central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and connecting portions that connect adjacent protrusions among the plurality of protrusions. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to connect to a horn antenna having a circular waveguide terminal while maintaining good reflection characteristics and axial ratio characteristics, without increasing the length in the tube axial direction. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in the circular polarizer according to the first embodiment. FIG. [Figure 2] 1 is a side view of the circular polarizer according to the first embodiment, showing mainly a pair of ridges with the waveguide seen through, viewed from the direction of a line connecting the central axes of the pair of ridges. FIG. [Figure 3]2 is a side view of the circular polarizer according to the first embodiment, seen through the waveguide and mainly showing a pair of ridges, from a direction perpendicular to a line connecting the central axes of the pair of ridges. FIG. [Figure 4] 1 is a perspective view showing a pair of ridges in a circular polarizer according to a first embodiment. FIG. [Figure 5] 1 is a side view showing a pair of ridges in a circular polarizer according to a first embodiment, viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 6] FIG. 2 is a perspective view corresponding to FIG. 1 showing the electric field direction when a horizontal linearly polarized signal (X-polarized signal) and a vertical linearly polarized signal (Y-polarized signal) are input to one of the waveguide input / output terminals in the circular polarizer according to the first embodiment. [Figure 7] 2 is a side view of the circular waveguide polarizer according to the first embodiment, showing a pair of ridges, viewed from the direction of a line connecting the central axes of the pair of ridges and from a direction perpendicular to the line. FIG. [Figure 8] 8 is a cross-sectional view schematically showing the electric field directions of two linearly polarized signals at cross sections AA and BB in FIG. 7 in the circular polarizer according to the first embodiment. [Figure 9] 1 is a perspective view showing a representative structure of a pair of opposing ridges each having one protrusion in the circular polarizer according to the first embodiment. FIG. [Figure 10] FIG. 3 is a diagram showing phase characteristics in the circular polarizer according to the first embodiment. [Figure 11] 4 is a diagram showing reflection characteristics in the circular polarizer according to the first embodiment. FIG. [Figure 12] 10 is a side view of a circular waveguide polarizer according to a reference example, showing a pair of ridges, viewed from the direction of a line connecting the central axes of the pair of ridges and from a direction perpendicular to the line. FIG. [Figure 13] 8A and 8B are cross-sectional views schematically showing the electric field directions of two linearly polarized signals at cross sections AA and BB in FIG. 7 in a circular polarizer according to a reference example. [Figure 14]FIG. 10 is a perspective view showing a representative structure of a pair of opposing ridges each having one protrusion in a circular waveguide polarizer according to a reference example. [Figure 15] FIG. 10 is a diagram showing phase characteristics in a circular polarizer according to a reference example. [Figure 16] FIG. 10 is a diagram showing reflection characteristics in a circular waveguide polarizer according to a reference example. [Figure 17] 10 is a perspective view showing mainly a pair of ridges seen through a waveguide in a circular polarizer according to a second embodiment. FIG. [Figure 18] FIG. 10 is a side view of the circular polarizer according to the second embodiment, seen through the waveguide and mainly showing a pair of ridges, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 19] 10 is a side view of the circular polarizer according to the second embodiment, seen through the waveguide and mainly showing a pair of ridges, as viewed from a direction perpendicular to a line connecting the central axes of the pair of ridges. FIG. [Figure 20] FIG. 10 is a perspective view showing a pair of ridges in a circular polarizer according to a second embodiment. [Figure 21] FIG. 10 is a side view showing a pair of ridges in a circular polarizer according to a second embodiment, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 22] 10 is a perspective view showing mainly a pair of ridges seen through a waveguide in a circular polarizer according to a third embodiment. FIG. [Figure 23] FIG. 11 is a side view of the circular polarizer according to the third embodiment, showing mainly a pair of ridges with the waveguide seen through, viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 24] FIG. 11 is a side view of a circular polarizer according to a third embodiment, seen through a waveguide and mainly showing a pair of ridges, as viewed from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 25] FIG. 11 is a perspective view showing a pair of ridges in a circular polarizer according to a third embodiment. [Figure 26] FIG. 11 is a side view showing a pair of ridges in a circular polarizer according to a third embodiment, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 27] FIG. 10 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in a circular polarizer according to a fourth embodiment. [Figure 28] FIG. 10 is a side view of a circularly polarized wave generator according to a fourth embodiment, showing mainly a pair of ridges with the waveguide seen through, viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 29] FIG. 10 is a side view of a circularly polarized wave generator according to a fourth embodiment, showing mainly a pair of ridges with the waveguide seen through, from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 30] FIG. 10 is a perspective view showing a pair of ridges in a circular polarizer according to a fourth embodiment. [Figure 31] FIG. 10 is a side view showing a pair of ridges in a circular polarizer according to a fourth embodiment, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 32] FIG. 11 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in a circular polarizer according to a fifth embodiment. [Figure 33] FIG. 11 is a side view of a circularly polarized light generator according to a fifth embodiment, showing mainly a pair of ridges with the waveguide seen through, viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 34] FIG. 11 is a side view of a circularly polarized wave generator according to a fifth embodiment, seen through a waveguide and mainly showing a pair of ridges, from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 35] FIG. 13 is a perspective view showing a pair of second ridges in a circular polarizer according to a fifth embodiment. [Figure 36] FIG. 20 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in a circular polarizer according to a sixth embodiment. [Figure 37] FIG. 13 is a side view of a circularly polarized wave generator according to a sixth embodiment, showing mainly a pair of ridges with the waveguide seen through, viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 38]FIG. 13 is a side view of a circularly polarized wave generator according to a sixth embodiment, showing mainly a pair of ridges with the waveguide seen through, from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 39] FIG. 13 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in a circular polarizer according to a seventh embodiment. [Figure 40] FIG. 13 is a side view of the circular polarizer according to the seventh embodiment, seen through the waveguide and mainly showing a pair of ridges, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 41] FIG. 13 is a side view of a circularly polarized wave generator according to a seventh embodiment, showing mainly a pair of ridges with the waveguide seen through, from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 42] FIG. 20 is a perspective view showing mainly a pair of ridges, seen through a waveguide, in a circular polarizer according to an eighth embodiment. [Figure 43] FIG. 20 is a side view of the circular polarizer according to the eighth embodiment, seen through the waveguide and mainly showing a pair of ridges, as viewed from the direction of a line connecting the central axes of the pair of ridges. [Figure 44] FIG. 20 is a side view of a circularly polarized light generator according to an eighth embodiment, showing mainly a pair of ridges with the waveguide seen through, from a direction perpendicular to a line connecting the central axes of the pair of ridges. [Figure 45] FIG. 20 is a perspective view showing a pair of second ridges in a circular polarizer according to an eighth embodiment. [Figure 46] 13 is a side view showing a pair of second ridges in a circular polarizer according to an eighth embodiment, viewed from a direction perpendicular to a line connecting the central axes of the pair of second ridges. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 The circular polarizer according to the first embodiment will be described with reference to FIGS. 1 to 11. FIG. The circular polarizer is used primarily in the VHF, UHF, microwave, and millimeter wave bands and is connected to a horn antenna with a circular waveguide terminal. When two orthogonal linearly polarized signals, i.e., a vertical linearly polarized signal and a horizontal linearly polarized signal, are input to a circular polarizer, a 90-degree phase difference occurs between the two orthogonal linearly polarized signals and they are output.

[0010] Based on this principle, in a circular polarizer comprising a circular waveguide having a first input / output terminal at one end and a second input / output terminal at the other end, and a pair of ridges with a central axis parallel to the axis of the waveguide and arranged opposite each other on the inner wall surface of the waveguide, for example, when a linearly polarized signal tilted 45 degrees to the right with respect to the line segment connecting the pair of ridges is input, a right-handed circularly polarized signal is output from the second input / output terminal, and when a linearly polarized signal tilted 45 degrees to the left with respect to the line segment connecting the pair of ridges is input, a left-handed circularly polarized signal is output from the second input / output terminal.

[0011] The circular polarizer comprises a circular waveguide 10 and a pair of ridges 20, 30. Waveguide 10 is a hollow cylindrical waveguide having a circular first input / output terminal 11 at one end and a circular second input / output terminal 12 at the other end, and having a hollow portion 13 with a circular cross section. In the waveguide 10, the hollow portion 13 forms a waveguide for propagating electromagnetic waves, one end of the waveguide forms a first input / output terminal 11, and the other end of the waveguide forms a second input / output terminal 12.

[0012] A second input / output terminal 12 is connected to a circular waveguide terminal of a horn antenna (not shown). A circularly polarized signal output from second input / output terminal 12 is propagated to the horn antenna via the circular waveguide terminal of the horn antenna, and an electromagnetic wave signal is radiated from the horn antenna into the air.

[0013] In the following description, an axis parallel to the tube axis of the waveguide 10 is referred to as the Z axis, a horizontal plane perpendicular to the tube axis of the waveguide 10 is referred to as the first plane, and two axes that intersect at right angles on the first plane are referred to as the X axis and Y axis. That is, in the first embodiment, the first plane is an XY plane centered on the tube axis of the waveguide 10.

[0014] The pair of ridges 20, 30 have central axes parallel to the axis of the waveguide 10 and are arranged opposite each other on the inner wall surface of the waveguide 10. The pair of ridges 20 and 30 have a symmetrical structure with respect to a third plane, which is a vertical plane that passes through the tube axis that is the central axis of the waveguide 10 and is parallel to the tube axis of the waveguide 10 .

[0015] In the first embodiment, the third plane is an XZ plane including the tube axis of the waveguide 10 and is a plane perpendicular to the line connecting the central axes of the pair of ridges 20 and 30 . In the first embodiment, a plane including a line connecting the tube axis of the waveguide 10 and the central axes of the pair of ridges 20, 30 is defined as a YZ plane, which is also called a second plane.

[0016] The pair of ridges 20, 30 are integral with the waveguide 10. Each of the pair of ridges 20, 30 has a first input / output end 21, 31 at one end, a second input / output end 22, 32 at the other end, and an intermediate portion 23, 33 between the first input / output end 21, 31 and the second input / output end 22, 32.

[0017] The first input / output end portions 21, 31 have a uniform length along the line connecting the central axes of the pair of ridges 20, 30 (Y-axis direction) over their entire length, and a uniform length along the line perpendicular to the line connecting the central axes of the pair of ridges 20, 30 (X-axis direction) over their entire length. Hereinafter, the length in the X-axis direction will be referred to as the width, the length in the Y-axis direction will be referred to as the height, and the length in the Z-axis direction will be referred to as the length.

[0018] That is, in each of the first input / output ends 21, 31, the width is the same over the entire length in the Z-axis direction, and the height is the same over the entire length in the Z-axis direction. The boundary surface between each of the first input / output ends 21 and 31 and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. The opposing surface of each of the first input / output terminals 21 and 31 that faces the boundary surface is rectangular and is a flat surface parallel to the XZ plane. The first input / output end 21 and the first input / output end 31 have the same size and shape.

[0019] In each of the second input / output ends 22, 32, the width is constant over the entire length in the Z-axis direction, and the height is constant over the entire length in the Z-axis direction. The boundary surface between each of the second input / output end portions 22 and 32 and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. The opposing surfaces of the second input / output terminals 22 and 32 facing the boundary surfaces are rectangular and are planes parallel to the XZ plane. The second input / output end 22 and the second input / output end 32 have the same size and shape.

[0020] In the ridge 20, the opposing surfaces at the first input / output end 21 and the opposing surfaces at the second input / output end 22 are in the same XZ plane. In the ridge 30, the opposing surfaces at the first input / output end 31 and the opposing surfaces at the second input / output end 32 are in the same XZ plane.

[0021] The intermediate portions 23 and 33 are formed by a plurality of protrusions 23a1 to 23a2 that are periodically provided in the axial direction of the waveguide 10, i.e., in the Z-axis direction. N , 33a1~33a N and a plurality of protrusions 23a1 to 23a N , 33a1~33a N The connecting portions 23b1 to 23b connecting adjacent protrusions in N-1 , 33b1~33b N-1 It has. A plurality of protrusions 23a1 to 23a N , 33a1~33a NThe connecting portions 23b1 to 23bb are arranged in a direction perpendicular to the line connecting the central axes of the pair of ridges 20 and 30 in a first plane perpendicular to the tube axis of the waveguide 10, i.e., in the XY plane. N , 33b1~33b N More prominent.

[0022] A plurality of protrusions 23a1 to 23a N , 33a1~33a N Each has a rectangular cross section parallel to a third plane, the XZ plane. A plurality of protrusions 23a1 to 23a N In this case, the length in the direction (X-axis direction) along a line perpendicular to the line connecting the central axes of the pair of ridges 20, 30, i.e., the horizontal width W, becomes progressively shorter from the central protrusion on the central axis of the ridge 20 toward the first input / output end 21 and the second input / output end 22, respectively.

[0023] The central protrusion on the central axis of the ridge 20 is the protrusion 23a when N is an odd number. (N+1) / 2 and for even numbers, 23a N / 2 and 23a (N+2) / 2 is. In the following description, the central protrusion is referred to as protrusion 23a N / 2 It will be explained as follows. A plurality of protrusions 23a1 to 23a N Width W in n (n is 1 to N) have the following relationship in the first embodiment: W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N

[0024] A plurality of protrusions 23a1 to 23a N Width W in n The relationship is shown by the dashed line W in Figure 5. Line As shown in FIG. 1, the central protrusion 23a N / 2 It is preferable that the length of the first input / output terminal 21 and the second input / output terminal 22 become shorter in a trigonometric function fashion from the apex. A plurality of protrusions 23a1 to 23a N Width W in n By changing the shape of the reflector in a trigonometric function manner, the shape changes gradually, thereby achieving better reflection characteristics.

[0025] A plurality of protrusions 23a1 to 23a N In this case, the protrusion 23a at the center of the central axis of the ridge 20 N / 2 The length in the Z-axis direction, that is, the vertical width L, decreases sequentially from the first input / output end 21 to the second input / output end 22. A plurality of protrusions 23a1 to 23a N The vertical width L n In the first embodiment, the following relationship exists: L1 <L2<···<L (N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0026] A plurality of protrusions 23a1 to 23a N , the length in the direction along the line connecting the central axes of the pair of ridges 20, 30 (Y-axis direction), that is, the height H, is the same. A plurality of protrusions 23a1 to 23a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 23a1 to 23a N The opposing surface facing the boundary surface in is rectangular and is a plane parallel to the XZ plane. The ridge 20 has a plurality of protrusions 23a1 to 23a N The opposing surfaces at the first input / output end 21 and the second input / output end 22 are in the same XZ plane.

[0027] A plurality of protrusions 33a1 to 33a N, the width W gradually decreases from the central protrusion on the central axis of the ridge 30 toward the first input / output end 31 and the second input / output end 32, respectively. A plurality of protrusions 33a1 to 33a N Width W in n (n is 1 to N) has the following relationship: W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N

[0028] A plurality of protrusions 33a1 to 33a N Width W in n The relationship is shown by the dashed line W in Figure 5. Line As shown in Fig. 1, the central protrusion 33a N / 2 It is preferable that the length of the first input / output terminal 31 and the second input / output terminal 3 become shorter in a trigonometric function fashion from the apex.

[0029] A plurality of protrusions 33a1 to 33a N In this case, the protrusion 33a at the center of the central axis of the ridge 30 N / 2 The vertical width L gradually decreases from the first input / output end 31 to the second input / output end 32. A plurality of protrusions 33a1 to 33a N The vertical width L n In the first embodiment, the following relationship exists: L1 <L2<···<L (N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0030] A plurality of protrusions 33a1 to 33a N The height H is the same. A plurality of protrusions 33a1 to 33a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 33a1 to 323a N The opposing surface facing the boundary surface in is rectangular and is a plane parallel to the XZ plane. The ridge 30 has a plurality of protrusions 33a1 to 33a N The opposing surfaces at the first input / output end 31 and the second input / output end 32 are in the same XZ plane.

[0031] Connecting parts 23b1~23b N-1 , 33b1~33b N-1 Each has a rectangular cross section parallel to a third plane, the XZ plane. Connecting parts 23b1~23b N-1 The length in the X-axis direction, that is, the width W0, of the protrusions 23a1 to 23a N The minimum widths W1 and W N It is shorter and has the same width as the first input / output end 31 and the second input / output end 32 . Connecting parts 23b1~23b N-1 The lengths in the Z-axis direction, i.e., the vertical widths L0, of the protrusions 23a1 to 23a N are placed at equal intervals.

[0032] Connecting parts 23b1~23b N-1 The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 23b1~23b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0033] In the ridge 20, the connecting portions 23b1 to 23b N-1 The opposing surfaces of the first input / output end 21, the second input / output end 22, and the plurality of protrusions 23a1 to 23a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 20 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface in the XZ plane.

[0034] Connecting parts 33b1~33b N-1 The length in the X-axis direction, that is, the width W0, of the protrusions 33a1 to 33a N The minimum widths W1 and W N It is shorter and has the same width as the first input / output end 31 and the second input / output end 32 . Connecting parts 33b1~33b N-1 The lengths in the Z-axis direction, i.e., the vertical widths L0, of the protrusions 33a1 to 33a N are placed at equal intervals.

[0035] Connecting parts 33b1~33b N-1 The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 33b1~33b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0036] In the ridge 30, the connecting portions 33b1 to 33b N-1 The opposing surfaces of the first input / output end 31, the second input / output end 32, and the plurality of protrusions 33a1 to 33a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 30 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface in the XZ plane. The opposing surface of the ridge 20 and the opposing surface of the ridge 30 face each other.

[0037] Next, we will explain the case in which two orthogonal linearly polarized signals are input to first input / output terminal 11 of waveguide 10 in the circular polarizer according to embodiment 1, as shown by the solid and dashed lines in Figure 6. The linearly polarized signal indicated by the dashed line is a horizontal linearly polarized signal that indicates the direction of the electric field of the electromagnetic wave in the X-axis direction, and the linearly polarized signal indicated by the solid line is a vertical linearly polarized signal that indicates the direction of the electric field of the electromagnetic wave in the Y-axis direction.

[0038] Now, as shown in Figure 7, the width W n The protrusion 23a has n , 33a n The connecting portion 23b has a cross section BB of the XY plane and a width W0 n-1 , 33b n-1 FIG. 8 shows the electric field of the electromagnetic wave at the AA cross section of the XY plane. The ridges 20, 30 in the circular polarizer according to the first embodiment are formed with widths that change periodically in the axial direction of the waveguide 10. For example, the periodic structure in which the width is narrow at the AA cross section and wide at the BB cross section generates a phase difference in the electromagnetic waves propagating through the waveguide.

[0039] Moreover, the ridges 20 and 30 in the circular waveguide polarizer according to the first embodiment have protruding portions 23a1 to 23a2 with different widths. N , 33a1~33a N In order to form a periodic structure in which the protrusions 23a1 to 23a N , 33a1~33a N By appropriately selecting the width W, a desired phase difference can be obtained in a desired frequency band, and a desired axial ratio characteristic can be realized.

[0040] As a result, in the circular waveguide polarizer according to the first embodiment, the plurality of protrusions 23a1 to 23a2 on the ridges 20 and 30 N , 33a1~33a N By appropriately designing the shape of the antenna, particularly the width W, a desired phase difference can be obtained in a selected frequency band, mainly in the VHF band, UHF band, microwave band, and millimeter wave band, and a circularly polarized signal with a desired axial ratio characteristic can be obtained.

[0041] The verification results of the transmission characteristics of linearly polarized signals, that is, the phase characteristics which are the transmission phase difference between two linearly polarized signals, and the reflection characteristics obtained by electromagnetic field analysis of the circular polarizer according to the first embodiment will be described with reference to Figs. 9 to 11. FIG. 9 shows a structure in which one protrusion 23a, 33a is provided on each of a pair of opposing ridges 20A, 30A. In FIG. 9, the direction of the electric field of the electromagnetic wave of the horizontal linearly polarized signal is indicated by a broken line, and the direction of the electric field of the electromagnetic wave of the vertical linearly polarized signal is indicated by a solid line.

[0042] FIG. 10 shows the verification results of the phase characteristics, which are the transmission phase difference versus normalized frequency, obtained by electromagnetic field analysis using a structure in which one protrusion 23a, 33a shown in FIG. 9 is formed on each of a pair of ridges 20A, 30A. FIG. 11 shows the verification results of the reflection characteristics, which are the transmission line characteristics versus normalized frequency, obtained by electromagnetic field analysis. In FIG. 10, the horizontal axis represents the normalized frequency, and the vertical axis represents the phase difference. In FIG. 11, the horizontal axis represents normalized frequency, the vertical axis represents reflection coefficient, the dashed line represents reflection characteristics due to horizontal linearly polarized signals, and the solid line represents reflection characteristics due to vertical linearly polarized signals.

[0043] When the phase difference between two orthogonal linearly polarized signals is set to approximately 10 degrees as shown in Figure 10 using a structure in which one protrusion 23a, 33a is formed on each of a pair of opposing ridges 20A, 30A, the reflection characteristics of the two orthogonal linearly polarized signals are approximately the same level as shown in Figure 11. Therefore, the difference in transmission loss between two orthogonal linearly polarized signals is reduced.

[0044] By connecting a plurality of protrusions 23a and 33a to each of the pair of ridges 20A and 30A, a phase difference of 90 degrees between the two orthogonal linearly polarized signals can be achieved. Even when the phase difference between two orthogonal linearly polarized signals is set to 90° by connecting multiple protrusions 23a, 33a, as can be seen from the reflection characteristics shown in Figure 1, the reflection characteristics for each of the two orthogonal linearly polarized signals are approximately the same level, and the difference in transmission loss between the two orthogonal linearly polarized signals is reduced.

[0045] To achieve good axial ratio characteristics, it is desirable that the passing amplitudes of the two orthogonal linearly polarized signals are the same and that the passing phase difference is a desired value. As can be seen from Figures 10 and 11, the circular polarizer according to embodiment 1 achieves good axial ratio characteristics.

[0046] For comparison with the circularly polarized wave generator according to the first embodiment, the following description will discuss a case where a pair of opposing ridges 20', 30' each has a groove extending from the opposing surface toward the inner wall surface of the waveguide. 23´a 1 ~23´a N 、33´a 1 ~33´a N A circular polarizer having a comb-like shape in which a circular polarizer having ... has a comb-like shape in which a circular polarizer has a comb-like shape in which a circular polarizer has a comb-like shape in which a circular polarizer has a comb-like shape in which a circular polarizer has a comb-like shape in which a circular polarizer has a comb-like shape

[0047] As shown in FIG. 12, the pair of ridges 20′ and 30′ in the reference example have a structure in which the opposing surfaces of the pair of ridges 20′ and 30′ are located on a plane parallel to the XZ plane, and grooves 23′a1 to 23′a2 extend from the opposing surfaces toward the inner wall surface of the waveguide. N , 33´a1~33´a N The shape is a comb-like shape. Depth D shown in Figure 12 n Groove 23´a n , 33´a n The cross section BB of the XY plane and the groove 23'a having a height H n , 33´a n The opposing surface 23'b adjacent to n-1 , 33´b n-1 FIG. 13 shows the electric field of the electromagnetic wave at the AA cross section of the XY plane. In FIG. 13, the direction of the electric field of the electromagnetic wave of the horizontal linearly polarized signal is indicated by a broken line, and the direction of the electric field of the electromagnetic wave of the vertical linearly polarized signal is indicated by a solid line.

[0048] In the circularly polarized wave generator according to the reference example, the ridges 20' and 30' are formed in the waveguide 10 in the axial direction by grooves 23'a. n , 33´a n Depth D nBy periodically changing the phase, for example, the phase is low at the BB cross section and high at the AA cross section, which creates a phase difference in the electromagnetic waves propagating through the waveguide.

[0049] FIG. 14 shows the structure of one comb in which a pair of opposing ridges 20'A, 30'A each have one groove 23'a, 33'a. In FIG. 14, the direction of the electric field of the electromagnetic wave of the horizontal linearly polarized signal is indicated by a broken line, and the direction of the electric field of the electromagnetic wave of the vertical linearly polarized signal is indicated by a solid line.

[0050] Figure 15 shows the verification results of the phase characteristics, which are the transmission phase difference against the normalized frequency obtained by electromagnetic field analysis for a structure in which one groove 23'a, 33'a shown in Figure 14 is formed in each of a pair of opposing ridges 20'A, 30'A, and Figure 16 shows the verification results of the reflection characteristics, which are the transmission line characteristics against the normalized frequency obtained by electromagnetic field analysis. In FIG. 15, the horizontal axis represents the normalized frequency, and the vertical axis represents the phase difference. In FIG. 16, the horizontal axis represents normalized frequency, the vertical axis represents reflection coefficient, the dashed line represents reflection characteristics due to horizontal linearly polarized signals, and the solid line represents reflection characteristics due to vertical linearly polarized signals.

[0051] When the phase difference between two orthogonal linearly polarized signals obtained by a structure in which one groove 23'a, 33'a is formed on each of a pair of ridges 20'A, 30'A is set to approximately 10 degrees as shown in Figure 15, similar to the phase difference between two orthogonal linearly polarized signals obtained by a structure in which one protrusion 23a, 33a is formed on each of a pair of ridges 20A, 30A as shown in Figure 9, the reflection characteristics of the two orthogonal linearly polarized signals show significantly different reflection characteristics as shown in Figure 16.

[0052] As is clear from the reflection characteristics of the structure in which one protrusion 23a, 33a is formed on each of a pair of ridges 20A, 30A for the circular polarizer according to embodiment 1 shown in Figure 11 and the reflection characteristics of the structure in which one groove 23'a, 33'a is formed on each of a pair of ridges 20'A, 30'A for the circular polarizer according to the reference example shown in Figure 16, the circular polarizer according to embodiment 1 achieves better axial ratio characteristics than the circular polarizer according to the reference example.

[0053] A method for manufacturing the circular polarizer according to the first embodiment will be described. The circular polarizer according to the first embodiment is manufactured by molding the waveguide 10 and the pair of ridges 20, 30 into two integral components separated by the XZ plane including the axis of the waveguide 10, for example, by aluminum die casting using an upper mold and a lower mold, and then joining the two integral components together.

[0054] The circular polarizer according to embodiment 1 may also be manufactured by additively manufacturing a tubular body by resin injection molding, integrating the waveguide 10 and the pair of ridges 20, 30, and then metal plating the entire inner surface of the tubular body to form a plating layer.

[0055] Furthermore, the circular polarizer according to embodiment 1 may be manufactured by additive manufacturing using a metal 3D printer with additive manufacturing technology to integrate the waveguide 10 and the pair of ridges 20, 30 from the second input / output terminal 12 toward the first input / output terminal 11. When manufacturing using a metal 3D printer with additive manufacturing technology, additive manufacturing is preferably performed with the modeling direction tilted 45 degrees from the axial direction of the waveguide 10. By performing additive manufacturing with the modeling direction tilted 45 degrees from the axial direction of the waveguide 10, the connecting portions 23b1 to 23b N-1 , 33b1~33b N-1 The protrusions 23a1 to 23a N , 33a1~33a N This can prevent the protruding parts from collapsing during additive manufacturing.

[0056] Furthermore, the circular polarizer according to embodiment 1 may be manufactured by additive manufacturing using a resin 3D printer with additive manufacturing technology, similar to additive manufacturing using a metal 3D printer, by integrating the waveguide 10 and the pair of ridges 20, 30 from the second input / output terminal 12 toward the first input / output terminal 11 to form a tube body, and then metal plating the entire inner surface of the tube body to form a plating layer.

[0057] The circular polarizer according to the first embodiment has a pair of ridges 20, 30 arranged opposite each other on the inner wall surface of a hollow waveguide 10 having a hollow portion with a circular cross section, and intermediate portions 23, 33 of each of the pair of ridges 20, 30 are periodically provided in the tube axis direction of the waveguide 10, and each of the intermediate portions 23, 33 has a plurality of protrusions 23a1 to 23a2 protruding in a direction along a line (line in the X direction) perpendicular to a line (line in the Y direction) connecting the central axes of the pair of ridges 20, 30 in a first plane (XY plane) perpendicular to the tube axis of the waveguide 10. N , 33a1~323a N , and a plurality of protrusions 23a1 to 23a N , 33a1~323a N The connecting portions 23b1 to 23b connecting adjacent protrusions in N-1 , 33b1~33b N-1 Therefore, good reflection characteristics and axial ratio characteristics can be obtained.

[0058] Furthermore, when connecting to a horn antenna having a circular waveguide terminal, a converter from a square waveguide to a circular waveguide is not required to connect to the horn antenna, and the length in the tube axial direction does not become long. Furthermore, the plurality of protrusions 23a1 to 23a N , 33a1~323a N By configuring the ridges 20, 30 so that their length (width) along a line perpendicular to the line connecting the central axes of the pair of ridges 20, 30 shortens in a trigonometric function fashion from the central protrusion at the center of the central axis of the ridges 20, 30 as the apex toward the first input / output end 21, 31 and the second input / output end 22, 32, the shape changes gradually, thereby achieving better reflection characteristics.

[0059] Embodiment 2 A circular polarizer according to the second embodiment will be described with reference to FIGS. The circular polarizer according to the second embodiment differs from the circular polarizer according to the first embodiment in that the plurality of protrusions 23a1 to 23aa at the intermediate portions 23 and 33 of the pair of ridges 20 and 30 are N , 33a1~33a N The cross section of each of the ridges 201 and 301 parallel to the third plane, which is the XZ plane, is rectangular, whereas the plurality of protrusions 231a1 to 231a2 at the intermediate portions 231 and 331 of the pair of ridges 201 and 301 are rectangular. N , 331a1-331a N The difference is that each cross section parallel to the third plane, which is the XZ plane, is a trapezoid, but otherwise they are the same. 17 to 21, the same reference numerals as those in FIGS. 1 to 5 indicate the same or corresponding parts.

[0060] The circular polarizer according to the second embodiment comprises a circular waveguide 10 and a pair of ridges 201 and 301. The pair of ridges 201 and 301 have central axes parallel to the axis of the waveguide 10 and are arranged opposite each other on the inner wall surface of the waveguide 10 . The pair of ridges 201 and 301 have a symmetrical structure with respect to a third plane passing through the axis of the waveguide 10 . The waveguide 10 and the pair of ridges 201, 301 are integrally formed.

[0061] Each of the pair of ridges 201, 301 has a first input / output end 211, 311 at one end, a second input / output end 221, 321 at the other end, and an intermediate portion 231, 331 between the first input / output end 211, 311 and the second input / output end 221, 321. The first input / output terminals 211 and 311 are the same as the first input / output terminals 21 and 31 in the circular polarizer according to the first embodiment. The second input / output terminals 221 and 321 are the same as the second input / output terminals 22 and 32 in the circular polarizer according to the first embodiment.

[0062] The intermediate portions 231 and 331 are made up of a plurality of protrusions 231a1 to 231a2 that are periodically provided in the axial direction of the waveguide 10, i.e., in the Z-axis direction. N , 331a1-331a N and a plurality of protrusions 231a1 to 231a N , 331a1-331a N The connecting portions 231b1 to 231b connecting the adjacent protrusions N-1 , 331b1-331b N-1 It has. A plurality of protrusions 231a1 to 231a N , 331a1-331a N The connecting portions 231b1 to 231b2 are arranged in a direction perpendicular to the central axis of the pair of ridges 201 and 301 in a first plane perpendicular to the tube axis of the waveguide 10, i.e., in the XY plane. N , 331b1-331b N More prominent.

[0063] A plurality of protrusions 231a1 to 231a N , 331a1-331a N Each has a trapezoidal cross section parallel to a third plane, the XZ plane. A plurality of protrusions 231a1 to 231a N In the trapezoidal cross section parallel to the third plane, the length of the lower base is N-1 The length of the upper base, i.e., the width W, is longer than the length of the lower base W0, and the lengths of the upper base and lower base become shorter from the central protrusion on the central axis of the ridge 201 toward the first input / output end 211 and the second input / output end 221, respectively.

[0064] A plurality of protrusions 231a1 to 231a N Width W in n (n is 1 to N, and corresponds to the length W of the upper base) has the following relationship in the second embodiment, as in the first embodiment. W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N A plurality of protrusions 231a1 to 231a N Width W in n The relationship is shown by the dashed line W in Figure 21. Line As shown in FIG. 1, the central protrusion 231a N / 2 It is preferable that the length of the first input / output terminal 211 and the second input / output terminal 221 become shorter in a trigonometric function fashion from the apex. A plurality of protrusions 231a1 to 231a N In the embodiment, the angle formed between the bottom and the legs is θ as shown in Fig. 21. θ is preferably equal to or greater than 45 degrees and less than 90 degrees. In the second embodiment, it is set to 45 degrees.

[0065] , A plurality of protrusions 231a1 to 231a N In this case, the protrusion 231a at the center of the central axis of the ridge 201 N / 2 The length in the Z-axis direction, that is, the vertical width L, decreases sequentially from the first input / output end 211 to the second input / output end 221. A plurality of protrusions 231a1 to 231a N The vertical width L n In the second embodiment, the following relationship exists, similar to the first embodiment. L1 <L2<···<L (N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0066] A plurality of protrusions 231a1 to 231a N The height H is the same. A plurality of protrusions 231a1 to 231a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 231a1 to 231a N The opposing surface opposite to the boundary surface in is an isosceles trapezoid and is a plane parallel to the XZ plane. The ridge 201 has a plurality of protrusions 231a1 to 231a N The opposing surfaces at the first input / output end 211 and the second input / output end 221 are in the same XZ plane.

[0067] A plurality of protrusions 331a1 to 331a N In the trapezoidal cross section parallel to the third plane, the length of the lower base is N-1 The length of the upper base, i.e., the width W, is longer than the length of the lower base W0, and the widths gradually decrease from the central protrusion on the central axis of the ridge 301 toward the first input / output end 311 and the second input / output end 322, respectively.

[0068] A plurality of protrusions 331a1 to 332a N Width W in n (n is 1 to N, and corresponds to the length W of the upper base) has the following relationship in the second embodiment, as in the first embodiment. W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N A plurality of protrusions 331a1 to 331a N Width W in n The relationship is shown by the dashed line W in Figure 21. Line As shown in FIG. 1, the central protrusion 331a N / 2 It is preferable that the length of the first input / output terminal 311 and the second input / output terminal 321 become shorter in a trigonometric function fashion from the apex. A plurality of protrusions 331a1 to 331a N In the embodiment, the angle between the bottom and the legs is θ as shown in Fig. 21. θ is preferably equal to or greater than 45 degrees and less than 90 degrees. In the second embodiment, it is set to 45 degrees.

[0069] A plurality of protrusions 331a1 to 331a N In this case, the protrusion 331a at the center of the central axis of the ridge 301 N / 2The length in the Z-axis direction, that is, the vertical width L, decreases sequentially from the first input / output end 311 to the second input / output end 321. A plurality of protrusions 331a1 to 331a N The vertical width L n In the second embodiment, the following relationship exists, similar to the first embodiment. L1 <L2<···<L (N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0070] A plurality of protrusions 331a1 to 331a N The height H is the same. A plurality of protrusions 331a1 to 331a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 331a1 to 331a N The opposing surface opposite to the boundary surface in is an isosceles trapezoid and is a plane parallel to the XZ plane. The ridge 301 has a plurality of protrusions 331a1 to 331a N The opposing surfaces at the first input / output end 311 and the second input / output end 321 are in the same XZ plane.

[0071] Connecting parts 231b1~231b N-1 , 331b1-331b N-1 Each has a rectangular cross section parallel to a third plane, the XZ plane. Connecting parts 231b1~231b N-1 All have the same width W0. Connecting parts 231b1~231b N-1 The vertical width L0 of each of the protrusions 231a1 to 231a N are placed at equal intervals.

[0072] Connecting parts 231b1~231b N-1The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 231b1~231b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0073] In the ridge 201, the connecting portions 231b1 to 231b N-1 The opposing surfaces of the first input / output end 211, the second input / output end 221, and the plurality of protrusions 231a1 to 231a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 201 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface in the XZ plane.

[0074] Connecting parts 331b1~331b N-1 All have the same width W0. Connecting parts 331b1~331b N-1 The vertical width L0 of each of the protrusions 331a1 to 331a N are placed at equal intervals. Connecting parts 331b1~331b N-1 The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 331b1~331b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0075] In the ridge 301, the connecting portions 331b1 to 331b N-1 The opposing surfaces of the first input / output end portion 311, the second input / output end portion 321, and the plurality of protrusions 331a1 to 331a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 301 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface in the XZ plane. The opposing surface of the ridge 201 and the opposing surface of the ridge 301 face each other.

[0076] The ridges 201 and 301 in the circular waveguide polarizer according to the second embodiment are made up of protrusions 231a1 to 231a2 that have different upper base lengths, i.e., different widths. N , 331a1-331a N In order to form a periodic structure in which the protrusions 231a1 to 231a N , 331a1-331a N By appropriately selecting the width W, a desired phase difference can be obtained in a desired frequency band, and a desired axial ratio characteristic can be realized.

[0077] As a result, in the circular waveguide polarizer according to the second embodiment, the plurality of protrusions 231a1 to 231a2 on the ridges 201 and 301 N , 331a1-331a N By appropriately designing the shape of the antenna, particularly the width W, a desired phase difference can be obtained in a selected frequency band, mainly in the VHF band, UHF band, microwave band, and millimeter wave band, and a circularly polarized signal with a desired axial ratio characteristic can be obtained.

[0078] A method for manufacturing the circular polarizer according to the second embodiment will be described. The circular polarizer of embodiment 2 is manufactured by additive manufacturing using a metal 3D printer with additive manufacturing technology to integrate the waveguide 10 and the pair of ridges 20, 30 along the tube axis of the waveguide 10 from the second input / output terminal 12 toward the first input / output terminal 11.

[0079] A plurality of protrusions 231a1 to 231a2 on each of a pair of ridges 201 and 301 in the circular waveguide polarizer according to the second embodiment N , 331a1-331a N Each of the connecting portions 231b1 to 231b2 has an isosceles trapezoidal cross section parallel to the third plane, which is the XZ plane, and the length of the lower base is equal to that of the connecting portion 231b1 to 231b2. N-1 , 331b1-331b N-1 The width W0 of the connecting portion 23b1 to 23b2 is the same as the width W0 of the connecting portion 23b1 to 23b2, and the angle between the bottom and the legs is θ (45≦θ<90). N-1 , 33b1~33b N-1The protrusions 23a1 to 23a N , 33a1~33a N The structure does not have a flat ceiling in the protruding part.

[0080] Therefore, even if metal powder is laid and solidified one layer at a time using a metal 3D printer to be sequentially layer-by-layer manufactured in the axial direction of the waveguide 10, the metal powder is layered at an angle θ in the axial direction of the waveguide 10 on the side surface formed by the upper and lower bases, so that the connecting portions 231b1 to 231b N-1 , 331b1-331b N-1 The protrusions 231a1 to 231a N , 331a1-331a N The protruding portion does not collapse, and the accuracy of the circular shape of the waveguide 10 is not impaired, thereby improving the molding accuracy.

[0081] The circular polarizer according to embodiment 2 may be manufactured by additive manufacturing using a metal 3D printer, using a resin 3D printer to integrate the waveguide 10 and the pair of ridges 201, 301 along the axis of the waveguide 10 from the second input / output terminal 12 toward the first input / output terminal 11 to form an additive manufacturing tube body, and then metal plating the entire inner surface of the tube body to form a plating layer, similar to manufacturing using additive manufacturing using a metal 3D printer.

[0082] Furthermore, the circular polarizer according to embodiment 2 may be manufactured by die molding in the same manner as in the manufacture of the circular polarizer according to embodiment 1, by producing two separate integrated components for waveguide 10 and pair of ridges 201, 301 by aluminum die casting using upper and lower molds, and then joining the two separate integrated components. Furthermore, the circular polarizer according to the second embodiment may be manufactured by additively manufacturing a tubular body by resin injection molding, integrating the waveguide 10 and the pair of ridges 201, 301, and then metal plating the entire inner surface of the tubular body to form a plating layer.

[0083] The circular polarizer according to the second embodiment has the same effects as the circular polarizer according to the first embodiment. Furthermore, in the circular waveguide polarizer according to the second embodiment, the protrusions 231a1 to 231a2 on the ridges 201 and 301 are N , 331a1-331a N Using a 3D printer with additive manufacturing technology, the waveguide 10 can be sequentially manufactured with high manufacturing accuracy in the axial direction without destroying the structure.

[0084] Embodiment 3 A circular polarizer according to the third embodiment will be described with reference to FIGS. 22 to 26. FIG. The circular polarizer according to the third embodiment differs from the circular polarizer according to the first embodiment in that the plurality of protrusions 23a1 to 23aa at the intermediate portions 23 and 33 of the pair of ridges 20 and 30 are N , 33a1~33a N Each of the ridges 202 and 302 has a rectangular cross section parallel to a third plane, which is an XZ plane, and a plurality of protrusions 232a1 to 232a2 at the intermediate portions 232 and 332 of the pair of ridges 202 and 302. N , 332a1-332a N The difference is that each has a hexagonal cross section parallel to the third plane, which is the XZ plane, but otherwise they are the same. 22 to 26, the same reference numerals as those in FIGS. 1 to 5 indicate the same or corresponding parts.

[0085] The circular polarizer according to the third embodiment comprises a circular waveguide 10 and a pair of ridges 202 and 302 . The pair of ridges 202 and 302 have central axes parallel to the axis of the waveguide 10 and are disposed opposite each other on the inner wall surface of the waveguide 10 . The pair of ridges 202 and 302 have a symmetrical structure with respect to a third plane passing through the axis of the waveguide 10 . The waveguide 10 and the pair of ridges 202, 302 are integrally formed.

[0086] Each of the pair of ridges 202, 302 has a first input / output end 212, 312 at one end, a second input / output end 222, 322 at the other end, and an intermediate portion 232, 332 between the first input / output end 212, 312 and the second input / output end 222, 322. The first input / output terminals 212 and 312 are the same as the first input / output terminals 21 and 31 in the circular polarizer according to the first embodiment. The second input / output terminals 222 and 322 are the same as the second input / output terminals 22 and 32 in the circular polarizer according to the first embodiment.

[0087] The intermediate portions 232 and 332 are formed by a plurality of protrusions 232a1 to 232a2 that are periodically provided in the axial direction of the waveguide 10, i.e., in the Z-axis direction. N , 332a1-332a N and a plurality of protrusions 232a1 to 232a N , 332a1-332a N The connecting portions 232b1 to 232b connecting adjacent protrusions in N-1 , 332b1-332b N-1 It has. A plurality of protrusions 232a1 to 232a N , 332a1-332a N The connecting portions 232b1 to 232b2 are arranged in a direction perpendicular to the line connecting the central axes of the pair of ridges 202 and 302 in a first plane perpendicular to the tube axis of the waveguide 10, i.e., in the XY plane. N , 332b1-332b N More prominent.

[0088] A plurality of protrusions 232a1 to 232a N , 332a1-332a N Each has a hexagonal cross section parallel to a third plane, the XZ plane. A plurality of protrusions 232a1 to 232a N In the hexagonal cross section parallel to the third plane, the lengths of a pair of opposite sides are N-1 and is symmetrical with respect to the YZ plane passing through the central axis of the ridge 202.

[0089] A plurality of protrusions 232a1 to 232a N In this case, it is vertically symmetrical with respect to the XY plane passing through the line connecting the left and right vertices of the hexagon. A plurality of protrusions 232a1 to 232a NIn the hexagon, the length connecting the left and right vertices, i.e., the width W, is longer than the length W0 of the opposite side, and is successively shorter from the central protrusion on the central axis of the ridge 202 toward the first input / output end 212 and the second input / output end 222, respectively.

[0090] A plurality of protrusions 232a1 to 232a N Width W in n In the third embodiment, (n is 1 to N) has the following relationship, similar to the first embodiment. W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N A plurality of protrusions 232a1 to 232a N Width W in n The relationship is shown by the dashed line W in Figure 26. Line As shown in FIG. 1, the central protrusion 232a N / 2 It is preferable that the length of the first input / output end 212 and the second input / output end 222 become shorter in a trigonometric function shape from the apex.

[0091] A plurality of protrusions 232a1 to 232a N 26, the angle formed between each opposite side and the oblique side on both sides of the central axis of the ridge 202 is θ. θ is preferably 45 degrees or more and less than 90 degrees. If the cross section of the protrusions 232a1 to 232a parallel to the XZ plane is a regular hexagon, θ is 60 degrees.

[0092] , A plurality of protrusions 232a1 to 232a N In this case, the protrusion 232a at the center of the central axis of the ridge 202 N / 2 The length in the Z-axis direction, that is, the vertical width L, decreases sequentially from the first input / output end 212 to the second input / output end 222. A plurality of protrusions 232a1 to 232a N The vertical width L n In the third embodiment, the following relationship exists, similar to the first embodiment. L1 <L2<···<L(N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0093] A plurality of protrusions 232a1 to 232a N The height H is the same. A plurality of protrusions 232a1 to 232a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 232a1 to 232a N The opposing surface facing the boundary surface in is a hexagon and is a plane parallel to the XZ plane. The ridge 202 has a plurality of protrusions 232a1 to 232a N The opposing surfaces at the first input / output end 212 and the second input / output end 222 are in the same XZ plane.

[0094] A plurality of protrusions 332a1 to 332a N In the hexagonal cross section parallel to the third plane, the lengths of a pair of opposite sides are N-1 and is symmetrical with respect to the YZ plane passing through the central axis of the ridge 302. A plurality of protrusions 332a1 to 332a N In this case, it is vertically symmetrical with respect to the XY plane passing through the line connecting the left and right vertices of the hexagon. A plurality of protrusions 332a1 to 332a N In the hexagon, the length connecting the left and right vertices, i.e., the width W, is longer than the length W0 of the opposite side, and is successively shorter from the central protrusion on the central axis of the ridge 302 toward the first input / output end 312 and the second input / output end 322, respectively.

[0095] A plurality of protrusions 332a1 to 332a N Width W in nIn the third embodiment, (n is 1 to N) has the following relationship, similar to the first embodiment. W1 <W2<···<W (N-2) / 2 <W N / 2 >W (N+2) / 2 >···>W N-1 >W N A plurality of protrusions 332a1 to 332a N Width W in n The relationship is shown by the dashed line W in Figure 26. Line As shown in FIG. 1, the central protrusion 332a N / 2 It is preferable that the length of the first input / output end 312 and the second input / output end 322 become shorter in a trigonometric function fashion from the apex.

[0096] A plurality of protrusions 332a1 to 332a N 26, the angle formed between each opposite side and the oblique side on both sides of the central axis of the ridge 302 is θ. It is preferable that θ is 45 degrees or more and less than 90 degrees. N If the cross section parallel to the XZ plane is a regular hexagon, then θ is 60 degrees.

[0097] , A plurality of protrusions 332a1 to 332a N In this case, the protrusion 332a at the center of the central axis of the ridge 302 N / 2 The length in the Z-axis direction, that is, the vertical width L, decreases sequentially from the first input / output end 312 to the second input / output end 322. A plurality of protrusions 332a1 to 332a N The vertical width L n In the third embodiment, the following relationship exists, similar to the first embodiment. L1 <L2<···<L (N-2) / 2 <L N / 2 >L (N+2) / 2 >···>L N-1 >L N In addition, the vertical width L n may all be the same length.

[0098] A plurality of protrusions 332a1 to 332aN The height H is the same. A plurality of protrusions 332a1 to 332a N The boundary surface with the inner wall surface of the waveguide 10 at this point is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. A plurality of protrusions 332a1 to 332a N The opposing surface facing the boundary surface in is a hexagon and is a plane parallel to the XZ plane. The ridge 302 has a plurality of protrusions 332a1 to 332a N The opposing surfaces at the first input / output end 312 and the second input / output end 322 are in the same XZ plane.

[0099] Connecting parts 232b1~232b N-1 , 332b1-332b N-1 Each has a rectangular cross section parallel to a third plane, the XZ plane. Connecting parts 232b1~232b N-1 All have the same width W0. Connecting parts 232b1~232b N-1 The vertical width L0 of each of the protrusions 232a1 to 232a N are placed at equal intervals.

[0100] Connecting parts 232b1~232b N-1 The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 232b1~232b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0101] In the ridge 202, the connecting portions 232b1 to 232b N-1 The opposing surfaces at the first input / output end 212, the second input / output end 222, and the plurality of protrusions 232a1 to 232a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 202 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface in the XZ plane. Central protrusion 232a N / 2 The ridge 202 is vertically symmetrical with respect to the XY plane passing through the line connecting the left and right vertices of the hexagon.

[0102] Connecting parts 332b1~332b N-1 All have the same width W0. Connecting parts 332b1~332b N-1 The vertical width L0 of each of the protrusions 332a1 to 332a N are placed at equal intervals. Connecting parts 332b1~332b N-1 The boundary surface between each of the waveguides and the inner wall surface of the waveguide 10 is an arcuate surface that follows the inner wall surface of the waveguide 10 relative to the XZ plane. Connecting parts 332b1~332b N-1 The opposing surface facing the boundary surface in each case is rectangular and is a plane parallel to the XZ plane.

[0103] In the ridge 302, the connecting portions 332b1 to 332b N-1 The opposing surfaces of the first input / output end 312, the second input / output end 322, and the plurality of protrusions 332a1 to 332a N It is in the same XZ plane as the opposing surface in That is, the surface of the ridge 302 that faces the arcuate surface along the inner wall surface of the waveguide 10 is a flat surface that lies in the XZ plane. Central protrusion 332a N / 2 The ridge 302 is vertically symmetrical with respect to the XY plane passing through the line connecting the left and right vertices of the hexagon. The opposing surface of the ridge 202 and the opposing surface of the ridge 302 face each other.

[0104] The ridges 202 and 302 in the circular waveguide polarizer according to the third embodiment are formed by protruding portions 232a1 to 232a2 that have different lengths connecting the left and right vertices of a hexagon, i.e., different widths. N , 332a1-332a NIn order to form a periodic structure in which the protrusions 232a1 to 232a N , 332a1-332a N By appropriately selecting the width W, a desired phase difference can be obtained in a desired frequency band, and a desired axial ratio characteristic can be realized.

[0105] As a result, the circular waveguide polarizer according to the third embodiment has a plurality of protrusions 232a1 to 232a2 on the ridges 202 and 302. N , 332a1-332a N By appropriately designing the shape of the antenna, particularly the width W, a desired phase difference can be obtained in a selected frequency band, mainly in the VHF band, UHF band, microwave band, and millimeter wave band, and a circularly polarized signal with a desired axial ratio characteristic can be obtained.

[0106] As with the circular polarizer according to embodiment 2, the circular polarizer according to embodiment 3 is manufactured by additive manufacturing using a metal 3D printer with additive manufacturing technology to integrate the waveguide 10 and the pair of ridges 20, 30 along the tube axis of the waveguide 10 from the second input / output terminal 12 toward the first input / output terminal 11.

[0107] A plurality of protrusions 232a1 to 232a on each of a pair of ridges 202 and 302 in the circular waveguide polarizer according to the third embodiment N , 332a1-332a N Each of the connecting portions 232b1 to 232b2 has a hexagonal cross section parallel to the third plane, which is the XZ plane, and the lengths of a pair of opposite sides are equal to each other. N-1 , 332b1-332b N-1 The angle between the opposite side and the oblique side is θ (45≦θ<90). N-1 , 331b1-331b N-1 The protrusions 231a1 to 231a N , 331a1-331a N The structure does not have a flat ceiling in the protruding part.

[0108] Therefore, even if metal powder is laid and solidified one layer at a time using a metal 3D printer to be sequentially layer-by-layer manufactured in the axial direction of the waveguide 10, the metal powder is layered in the axial direction of the waveguide 10 at an angle θ on the side formed by the opposite side and the oblique side located on the lower side. N-1 , 331b1-331b N-1 The protrusions 231a1 to 231a N , 331a1-331a N The protruding portion does not collapse, and the accuracy of the circular shape of the waveguide 10 is not impaired, thereby improving the molding accuracy.

[0109] The circular polarizer according to embodiment 3 may be manufactured by additive manufacturing using a resin 3D printer, similar to manufacturing using additive manufacturing with a resin 3D printer, by integrating the waveguide 10 and the pair of ridges 202, 302 along the tube axis of the waveguide 10 from the second input / output terminal 12 toward the first input / output terminal 11 to form an additive manufacturing tube body, and then metal plating the entire inner surface of the tube body to form a plating layer.

[0110] Furthermore, the circular polarizer according to embodiment 3 may be manufactured in the same manner as the circular polarizer according to embodiment 1 by molding a mold to produce two separate integral components for the waveguide 10 and the pair of ridges 202, 302 by aluminum die casting using an upper mold and a lower mold, and then joining the two separate integral components. Furthermore, the circular polarizer according to the third embodiment may be manufactured by additively manufacturing a tubular body by resin injection molding, integrating the waveguide 10 and the pair of ridges 202, 302, and then metal plating the entire inner surface of the tubular body to form a plating layer.

[0111] The circular polarizer according to the third embodiment has the same effects as the circular polarizer according to the first embodiment. Moreover, in each of the ridges 202 and 302, the central protrusion 232a N / 2 , 332a N / 2Since the ridges 202 and 302 are vertically symmetrical with respect to the XY plane passing through the line connecting the left and right vertices of the hexagon in FIG. 1, the symmetry in the tube axis direction is improved, and better reflection characteristics and axial ratio characteristics can be realized.

[0112] Furthermore, in the circular waveguide polarizer according to the third embodiment, the protrusions 231a1 to 231a2 on the ridges 202 and 302 are N , 331a1-331a N Using a 3D printer with additive manufacturing technology, the waveguide 10 can be sequentially manufactured with high manufacturing accuracy in the axial direction without destroying the structure.

[0113] Embodiment 4 A circular polarizer according to a fourth embodiment will be described with reference to FIGS. 27 to 31. FIG. In the circular polarizer according to embodiment 1, the first input / output end portions 21, 31 and the second input / output end portions 22, 32 of the pair of ridges 20, 30 have a uniform length along the line connecting the central axes of the pair of ridges 20, 30 over their entire length, and a uniform length along the line perpendicular to the line connecting the central axes of the pair of ridges 20, 30 over their entire length.

[0114] In contrast, the circular polarizer according to embodiment 4 differs from the circular polarizer according to embodiment 1 in that the first input / output end portions 21A, 31A of each of the pair of ridges 20A, 30A are tapered in length toward the first input / output terminal 11 in a second plane including the central axes of the pair of ridges 20A, 30A, and the second input / output end portions 22A, 32A of each of the pair of ridges 20A, 30A are tapered in length toward the second input / output terminal 12 in a second plane including the central axes of the pair of ridges 20A, 30A, but is otherwise the same. In Figures 27 to 31, the same reference numerals as those in Figures 1 to 5 indicate the same or corresponding parts.

[0115] Therefore, the following description will focus on the differences between the pair of ridges 20A and 30A, particularly the first input / output end portions 21A and 31A and the second input / output end portions 22A and 32A. The circular polarizer according to the fourth embodiment comprises a circular waveguide 10 and a pair of ridges 20A, 30A, and is integrally configured. The circular waveguide 10 is the same as the circular waveguide 10 in the circular polarizer according to the first embodiment, and therefore a description thereof will be omitted.

[0116] Each of the pair of ridges 20A, 30A has a first input / output end 21A, 31A at one end, a second input / output end 221, 321 at the other end, and an intermediate portion 23, 33 between the first input / output end 21A, 31A and the second input / output end 22A, 32A. Intermediate sections 23 and 33 are the same as intermediate sections 23 and 33 in the circular polarizer according to the first embodiment, and therefore a description thereof will be omitted.

[0117] The height (length in the Y-axis direction) of the first input / output end portions 21A, 31A gradually decreases from the protruding portions 23a1, 33a1 of the intermediate portions 23, 33 toward the first input / output terminal 11. The height of the first input / output terminals 21A and 31A preferably decreases in a trigonometric function manner, but may also decrease linearly. The width (length in the X-axis direction) of the first input / output end portions 21A and 31A is uniform over the entire length in the Z-axis direction, and the connecting portions 23b1 to 23b of the intermediate portions 23 and 33 N-1 , 33b1~33b N-1 The width is the same as W0.

[0118] The boundary surface between the first input / output end portions 21A and 31A and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. The opposing surface of the first input / output end portions 21A and 31A that faces the boundary surface is rectangular and is a flat surface that is inclined with respect to the XZ plane. The first input / output end portion 21A and the first input / output end portion 31A have the same size and shape.

[0119] The height of the second input / output end portions 22A and 32A is equal to the height of the protrusions 23a of the intermediate portions 23 and 33. N , 33a N The length gradually decreases from the first terminal 11 to the second input / output terminal 12. The height of the second input / output end portions 22A, 32A preferably decreases in a trigonometric function manner, but may also decrease linearly. The width of the second input / output end portions 22A and 32A is uniform over the entire length in the Z-axis direction, and the connecting portions 23b1 to 23b2 of the intermediate portions 23 and 33 N-1 , 33b1~33b N-1 The width is the same as W0.

[0120] The boundary surface between the second input / output end portions 22A and 32A and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the XZ plane. The opposing surface of the second input / output end portions 22A and 32A that faces the boundary surface is rectangular and is a flat surface that is inclined relative to the XZ plane. The second input / output end 22A and the second input / output end 32A have the same size and shape.

[0121] The circular polarizer according to the fourth embodiment is manufactured by die molding in the same manner as the circular polarizer according to the first embodiment. The circular optical polarizer according to embodiment 4 may be manufactured using a metal 3D printer with additive manufacturing technology, a resin 3D printer with additive manufacturing technology and metal plating, or resin injection molding and metal plating, as described for the circular optical polarizer according to embodiment 1.

[0122] The circular polarizer of embodiment 4 has the same effect as the circular polarizer of embodiment 1, and in addition, when viewed from the first input / output terminal 11 and the second input / output terminal 12, the heights of the ridges 20A and 30A change gradually, resulting in better reflection characteristics.

[0123] In the circular polarizer according to embodiment 2, the first input / output terminals 211 and 311 of the ridges 201 and 301, respectively, may have the same shapes as the first input / output terminals 21A and 31A of the ridges 20A and 30A, respectively, shown in the circular polarizer according to embodiment 4, and the second input / output terminals 221 and 321 of the ridges 201 and 301, respectively, may have the same shapes as the second input / output terminals 22A and 32A of the ridges 20A and 30A, respectively, shown in the circular polarizer according to embodiment 4.

[0124] That is, in the circularly polarized light generator according to the second embodiment, the height of each of the first input / output terminals 211 and 311 is gradually reduced from the protrusions 231a1 and 331a1 of the intermediate portions 231 and 331 toward the first input / output terminal 11, and the height of each of the second input / output terminals 221 and 321 is gradually reduced from the protrusions 231a1 and 331a1 of the intermediate portions 231 and 331 toward the first input / output terminal 11. N , 331a N Alternatively, the shape may be such that the length gradually decreases from the first input / output terminal 11 to the second input / output terminal 12.

[0125] In the circular polarizer according to embodiment 2, a circular polarizer in which the first input / output terminals 21A, 31A and the second input / output terminals 22A, 32A shown in the circular polarizer according to embodiment 4 are changed can also be manufactured using a metal 3D printer with additive manufacturing technology, as in the case of the circular polarizer according to embodiment 2, or can be manufactured using a resin 3D printer with additive manufacturing technology and metal plating, mold forming processing, or resin injection molding and metal plating.

[0126] Furthermore, in the circular polarizer according to embodiment 3, the first input / output terminals 212, 312 of the ridges 202, 302, respectively, may have the same shape as the first input / output terminals 21A, 31A of the ridges 20A, 30A, respectively, shown in the circular polarizer according to embodiment 4, and the second input / output terminals 222, 322 of the ridges 202, 302, respectively, may have the same shape as the second input / output terminals 22A, 32A of the ridges 20A, 30A, respectively, shown in the circular polarizer according to embodiment 4.

[0127] That is, in the circular waveguide polarizer according to the third embodiment, the height of each of the first input / output terminals 212 and 312 is gradually reduced from the protrusions 232a1 and 332a1 of the intermediate portions 232 and 332 toward the first input / output terminal 11, and the height of each of the second input / output terminals 222 and 322 is gradually reduced from the protrusions 232a1 and 332a1 of the intermediate portions 232 and 332 toward the first input / output terminal 11. N , 3321a N Alternatively, the shape may be such that the length gradually decreases from the first input / output terminal 11 to the second input / output terminal 12.

[0128] In the circular polarizer according to embodiment 3, a circular polarizer in which the first input / output terminals 21A, 31A and the second input / output terminals 22A, 32A shown in the circular polarizer according to embodiment 4 are changed can also be manufactured using a metal 3D printer with additive manufacturing technology, as in the manufacture of the circular polarizer according to embodiment 3, or can be manufactured using a resin 3D printer with additive manufacturing technology and metal plating, mold forming processing, or resin injection molding and metal plating.

[0129] Embodiment 5. A circular polarizer according to the fifth embodiment will be described with reference to FIGS. 32 to 35. FIG. The circular polarizer according to the fifth embodiment differs from the circular polarizer according to the first embodiment in that it has a pair of second ridges 40, 50, but is otherwise the same. In Figures 32 to 35, the same reference numerals as those in Figures 1 to 5 indicate the same or corresponding parts.

[0130] Therefore, the following description will focus on the pair of second ridges 40, 50, which are the difference. The circular polarizer according to the fifth embodiment comprises a circular waveguide 10, a pair of first ridges 20, 30, and a pair of second ridges 40, 50, and the waveguide 10, the pair of first ridges 20, 30, and the pair of second ridges 40, 50 are integrally configured. Each of the pair of second ridges 40, 50 has a central axis parallel to the tube axis of the waveguide 10, and is arranged opposite each other on the inner wall surface of the waveguide 10 rotated 90 degrees around the tube axis of the waveguide 10 relative to the pair of first ridges 20, 30.

[0131] The pair of second ridges 40 and 50 have a symmetrical structure with respect to a second plane (YZ plane) passing through the tube axis, which is the central axis of the waveguide 10. Each of the pair of second ridges 40, 50 has a length along a line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length, and a length along a line perpendicular to the line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length. Hereinafter, in the second ridges 40, 50, the length in the X-axis direction will be referred to as the height, the length in the Y-axis direction as the width, and the length in the Z-axis direction as the vertical width.

[0132] That is, in each of the second ridges 40, 50, as shown in FIG. 35, the width is constant over the entire length in the Z-axis direction, and the height is constant over the entire length in the Z-axis direction. The boundary surface between each of the second ridges 40 and 50 and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the YZ plane. The opposing surface of each of the second ridges 40, 50 that faces the boundary surface is rectangular and is a flat surface parallel to the YZ plane. The second ridge 40 and the second ridge 50 have the same size and shape.

[0133] From a design parameter perspective, it is preferable that the width of each of the second ridges 40, 50 is the same as the width of the first input / output end portions 21, 31 and the width of the second input / output end portions 22, 32, but they may be different widths. Furthermore, it is preferable that the heights of the second ridges 40, 50 are the same as the heights of the first input / output terminals 21, 31 and the second input / output terminals 22, 32 in terms of design parameters, but they may be different heights. Different widths and heights provide additional design parameters or better axial ratio and reflection characteristics.

[0134] The circular polarizer according to the fifth embodiment is manufactured by die molding, similar to the manufacturing method of the circular polarizer according to the first embodiment. The circular optical polarizer according to embodiment 5 may be manufactured using a metal 3D printer with additive manufacturing technology, a resin 3D printer with additive manufacturing technology and metal plating, or resin injection molding and metal plating, as described for the circular optical polarizer according to embodiment 1.

[0135] The circular polarizer according to embodiment 5 has the same effects as the circular polarizer according to embodiment 1, and in addition improves the symmetry of the cross section parallel to the XY plane (first plane) of waveguide 13, makes it easier to achieve a desired phase difference between two orthogonal linearly polarized signals, and obtains better axial ratio characteristics.

[0136] The pair of second ridges 40, 50 in the circular polarizer according to embodiment 5 may have the following shapes, similar to the pair of ridges 20, 30 in the circular polarizer according to embodiment 1. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0137] The intermediate portions of each of the pair of second ridges 40, 50 are arranged periodically in the tube axis direction of the waveguide 10, similar to the intermediate portions of each of the pair of ridges 20, 30 in the circular polarizer according to embodiment 1, and each has a plurality of protrusions that protrude in the XY plane (first plane) in a direction along a line connecting the central axes of the pair of first ridges 20, 30, and connecting portions that connect adjacent protrusions among the plurality of protrusions.

[0138] Furthermore, the pair of second ridges 40, 50 in the circular polarizer according to embodiment 5 may have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0139] One end of each of the pair of second ridges 40, 50 is tapered in length toward the first input / output terminal 11 in the XZ plane (third plane) including the central axis of the pair of second ridges 40, 50, similar to the first input / output ends 21A, 31A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. Furthermore, the other end of each of the pair of second ridges 40, 50 is tapered in length toward the second input / output terminal 12 in the XZ plane including the central axis of the pair of second ridges 40, 50, similar to the second input / output ends 22A, 32A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0140] Furthermore, the pair of first ridges 20, 30 in the circular polarizer according to embodiment 5 may each have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0141] That is, the first input / output terminals 21, 31 of the first ridges 20, 30, respectively, are made to have the same shape as the first input / output terminals 21A, 31A of the ridges 20A, 30A, respectively, shown in the circular polarizer according to embodiment 4, that is, the height gradually decreases from the protrusions 231a1, 331a1 of the intermediate portions 231, 331 toward the first input / output terminal 11. Furthermore, the second input / output terminals 22 and 32 of the first ridges 20 and 30, respectively, are provided with projections 231a having intermediate portions 231 and 331 in height, respectively, which are similar in shape to the second input / output terminals 22A and 32A of the ridges 20A and 30A shown in the circularly polarized wave generator according to the fourth embodiment. N , 331a N The shape of the terminal gradually becomes shorter from the first terminal to the second input / output terminal 12.

[0142] Embodiment 6 A circular polarizer according to the sixth embodiment will be described with reference to FIGS. The circular polarizer according to the sixth embodiment differs from the circular polarizer according to the second embodiment in that it has a pair of second ridges 40, 50, but is otherwise the same. 36 to 38, the same reference numerals as those in FIGS. 1 to 5 and 17 to 21 indicate the same or corresponding parts.

[0143] Therefore, the following description will focus on the pair of second ridges 40, 50, which are the difference. The circular polarizer according to the sixth embodiment comprises a circular waveguide 10, a pair of first ridges 201, 301, and a pair of second ridges 40, 50, and the waveguide 10, the pair of first ridges 201, 301, and the pair of second ridges 40, 50 are integrally configured. Each of the pair of second ridges 40, 50 has a central axis parallel to the tube axis of the waveguide 10, and is arranged opposite each other on the inner wall surface of the waveguide 10 rotated 90 degrees around the tube axis of the waveguide 10 relative to the pair of first ridges 201, 301.

[0144] The pair of second ridges 40 and 50 have a symmetrical structure with respect to a second plane (YZ plane) passing through the tube axis, which is the central axis of the waveguide 10. Each of the pair of second ridges 40, 50 has a length along a line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length, and a length along a line perpendicular to the line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length. Hereinafter, in the second ridges 40, 50, the length in the X-axis direction will be referred to as the height, the length in the Y-axis direction as the width, and the length in the Z-axis direction as the vertical width.

[0145] That is, in each of the second ridges 40, 50, the width is constant over the entire length in the Z axis direction, and the height is constant over the entire length in the Z axis direction, similar to the fifth embodiment shown in FIG. The boundary surface between each of the second ridges 40 and 50 and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the YZ plane. The opposing surface of each of the second ridges 40, 50 that faces the boundary surface is rectangular and is a flat surface parallel to the YZ plane. The second ridge 40 and the second ridge 50 have the same size and shape.

[0146] The width of each of the second ridges 40, 50 is preferably the same as the width of the first input / output end portions 211, 311 and the width of the second input / output end portions 221, 321 in terms of design parameters, but may be different widths. Furthermore, it is preferable from a design parameter standpoint that the heights of the second ridges 40, 50 are the same as the heights of the first input / output ends 211, 311 and the second input / output ends 221, 321, but they may be different heights. Different widths and heights provide additional design parameters or better axial ratio and reflection characteristics.

[0147] The circular optical polarizer according to embodiment 6 may be manufactured using a metal 3D printer with additive manufacturing technology, a resin 3D printer with additive manufacturing technology and metal plating, mold forming processing, or resin injection molding and metal plating, as in the case of the circular optical polarizer according to embodiment 2.

[0148] The circular polarizer according to the sixth embodiment has the same effects as the circular polarizer according to the second embodiment, and in addition, it improves the symmetry of the cross section parallel to the XY plane (first plane) of the waveguide 13, and it is easier to achieve a desired phase difference between two orthogonal linearly polarized signals, resulting in better axial ratio characteristics.

[0149] The pair of second ridges 40, 50 in the circular polarizer according to embodiment 6 may have the following shapes, similar to the pair of ridges 201, 301 in the circular polarizer according to embodiment 2. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0150] The intermediate portions of each of the pair of second ridges 40, 50 are arranged periodically in the tube axis direction of the waveguide 10, similar to the intermediate portions of each of the pair of ridges 201, 301 in the circular polarizer according to embodiment 2, and each has a plurality of protrusions that protrude in the XY plane (first plane) in a direction along a line connecting the central axes of the pair of first ridges 201, 301, and connecting portions that connect adjacent protrusions among the plurality of protrusions.

[0151] Furthermore, the pair of second ridges 40, 50 in the circular polarizer according to embodiment 6 may have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0152] One end of each of the pair of second ridges 40, 50 is tapered in length toward the first input / output terminal 11 in the XZ plane (third plane) including the central axis of the pair of second ridges 40, 50, similar to the first input / output ends 21A, 31A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. Furthermore, the other end of each of the pair of second ridges 40, 50 is tapered in length toward the second input / output terminal 12 in the XZ plane including the central axis of the pair of second ridges 40, 50, similar to the second input / output ends 22A, 32A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0153] Furthermore, the pair of first ridges 201, 301 in the circular polarizer according to embodiment 6 may each have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0154] That is, the first input / output terminals 211, 311 of the first ridges 201, 301, respectively, are made to have the same shape as the first input / output terminals 21A, 31A of the ridges 20A, 30A, respectively, shown in the circularly polarized wave generator of embodiment 4, that is, the height gradually decreases from the protrusions 231a1, 331a1 of the intermediate portions 231, 331 toward the first input / output terminal 11. Furthermore, the second input / output end portions 221 and 321 of the first ridges 201 and 301, respectively, are formed to have the same shape as the second input / output end portions 22A and 32A of the ridges 20A and 30A shown in the circularly polarized wave generator according to the fourth embodiment, that is, the projections 231a having intermediate portions 231 and 331 in height. N , 331a N The shape of the terminal gradually becomes shorter from the first terminal to the second input / output terminal 12.

[0155] Embodiment 7 A circular polarizer according to the seventh embodiment will be described with reference to FIGS. The circular polarizer according to the seventh embodiment differs from the circular polarizer according to the third embodiment in that it has a pair of second ridges 40, 50, but is otherwise the same. In Figures 39 to 41, the same reference numerals as those in Figures 1 to 5 and Figures 22 to 26 indicate the same or corresponding parts.

[0156] Therefore, the following description will focus on the pair of second ridges 40, 50, which are the difference. The circular polarizer according to the seventh embodiment comprises a circular waveguide 10, a pair of first ridges 202, 302, and a pair of second ridges 40, 50, and the waveguide 10, the pair of first ridges 202, 302, and the pair of second ridges 40, 50 are integrally configured. Each of the pair of second ridges 40, 50 has a central axis parallel to the tube axis of the waveguide 10, and is arranged opposite each other on the inner wall surface of the waveguide 10 rotated 90 degrees around the tube axis of the waveguide 10 relative to the pair of first ridges 202, 302.

[0157] The pair of second ridges 40 and 50 have a symmetrical structure with respect to a second plane (YZ plane) passing through the tube axis, which is the central axis of the waveguide 10. Each of the pair of second ridges 40, 50 has a length along a line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length, and a length along a line perpendicular to the line connecting the central axes of the pair of second ridges 40, 50 that is uniform over its entire length. Hereinafter, in the second ridges 40, 50, the length in the X-axis direction will be referred to as the height, the length in the Y-axis direction as the width, and the length in the Z-axis direction as the vertical width.

[0158] That is, in each of the second ridges 40, 50, the width is constant over the entire length in the Z axis direction, and the height is constant over the entire length in the Z axis direction, similar to the fifth embodiment shown in FIG. The boundary surface between each of the second ridges 40 and 50 and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the YZ plane. The opposing surface of each of the second ridges 40, 50 that faces the boundary surface is rectangular and is a flat surface parallel to the YZ plane. The second ridge 40 and the second ridge 50 have the same size and shape.

[0159] The lateral width of each of the second ridges 40, 50 is preferably the same as the lateral width of the first input / output end portions 212, 312 and the lateral width of the second input / output end portions 222, 322 in terms of design parameters, but may be different widths. Furthermore, it is preferable that the heights of the second ridges 40, 50 are the same as the heights of the first input / output ends 212, 312 and the second input / output ends 222, 322 in terms of design parameters, but they may be different heights. Different widths and heights provide additional design parameters or better axial ratio and reflection characteristics.

[0160] The circular optical polarizer according to embodiment 7 may be manufactured using a metal 3D printer with additive manufacturing technology, a resin 3D printer with additive manufacturing technology and metal plating, mold forming processing, or resin injection molding and metal plating, as in the case of the circular optical polarizer according to embodiment 3.

[0161] The circular polarizer according to the seventh embodiment has the same effects as the circular polarizer according to the third embodiment, and in addition, it improves the symmetry of the cross section parallel to the XY plane (first plane) of the waveguide 13, and it is easier to achieve a desired phase difference between two orthogonal linearly polarized signals, resulting in better axial ratio characteristics.

[0162] The pair of second ridges 40, 50 in the circular polarizer according to embodiment 7 may have the following shapes, similar to the pair of ridges 202, 302 in the circular polarizer according to embodiment 3. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0163] The intermediate portions of each of the pair of second ridges 40, 50 are arranged periodically in the tube axis direction of the waveguide 10, similar to the intermediate portions of each of the pair of ridges 202, 302 in the circular polarizer according to embodiment 3, and each has a plurality of protrusions that protrude in the XY plane (first plane) in a direction along a line connecting the central axes of the pair of first ridges 202, 302, and connecting portions that connect adjacent protrusions among the plurality of protrusions.

[0164] Furthermore, the pair of second ridges 40, 50 in the circular polarizer according to embodiment 7 may have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. That is, the pair of second ridges 40, 50 have one end, the other end, and an intermediate portion between the one end and the other end.

[0165] One end of each of the pair of second ridges 40, 50 is tapered in length toward the first input / output terminal 11 in the XZ plane (third plane) including the central axis of the pair of second ridges 40, 50, similar to the first input / output ends 21A, 31A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4. Furthermore, the other end of each of the pair of second ridges 40, 50 is tapered in length toward the second input / output terminal 12 in the XZ plane including the central axis of the pair of second ridges 40, 50, similar to the second input / output ends 22A, 32A of each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0166] Furthermore, the pair of first ridges 202, 302 in the circular polarizer according to embodiment 7 may each have the following shapes, similar to the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0167] That is, the first input / output ends 212, 312 of the first ridges 202, 302, respectively, are shaped similarly to the first input / output ends 21A, 31A of the ridges 20A, 30A, respectively, shown in the circular polarizer according to embodiment 4, that is, the height gradually decreases from the protrusions 231a1, 331a1 of the intermediate portions 231, 331 toward the first input / output terminal 11. Furthermore, the second input / output end portions 222 and 322 of the first ridges 202 and 302, respectively, are formed to have the same shape as the second input / output end portions 22A and 32A of the ridges 20A and 30A shown in the circularly polarized wave generator according to the fourth embodiment, that is, the projections 231a having intermediate portions 231 and 331 in height. N , 331a N The shape of the terminal gradually becomes shorter from the first terminal to the second input / output terminal 12.

[0168] Embodiment 8 A circular polarizer according to the eighth embodiment will be described with reference to FIGS. The circular polarizer according to the eighth embodiment differs from the circular polarizer according to the fourth embodiment in that it includes a pair of second ridges 40A, 50A, but is otherwise the same. 42 to 46, the same reference numerals as those in FIGS. 1 to 5 and 27 to 31 indicate the same or corresponding parts.

[0169] Therefore, the following description will focus on the pair of second ridges 40A, 50A, which are the difference. The circular polarizer according to the eighth embodiment comprises a circular waveguide 10, a pair of first ridges 20A, 30A, and a pair of second ridges 40A, 50A, and the waveguide 10, the pair of first ridges 20A, 30A, and the pair of second ridges 40A, 50A are integrally configured. Each of the pair of second ridges 40A, 50A has a central axis parallel to the tube axis of the waveguide 10, and is arranged opposite each other on the inner wall surface of the waveguide 10 rotated 90 degrees around the tube axis of the waveguide 10 relative to the pair of first ridges 20A, 30A.

[0170] The pair of second ridges 40A and 50A have a symmetrical structure with respect to a second plane (YZ plane) passing through the tube axis, which is the central axis of the waveguide 10. Each of the pair of second ridges 40A, 50A has one end 41A, 51A, the other end 42A, 52A, and an intermediate portion 43A, 53A between the one end 41A, 51A and the other end 42A, 52A. In each of the pair of second ridges 40A, 50A, one end 41A, 51A serves as a first input / output end, and the other end 42A, 52A serves as a 21st input / output end. Hereinafter, in the second ridges 40A and 50A, the length in the X-axis direction is referred to as the height, the length in the Y-axis direction as the width, and the length in the Z-axis direction as the vertical width.

[0171] As shown in particular in FIGS. 45 and 46, each of the second ridges 40A, 50A has the following shape. That is, one end portion 41A, 51A of each second ridge 40A, 50A is tapered in a third plane (XZ plane) including the central axes of the pair of second ridges 40A, 50A, with a length, i.e., height, that is short from one end of the intermediate portion 43A, 53A toward the first input / output terminal 11, and has a uniform length, i.e., horizontal width, in the direction along the line connecting the central axes of the pair of second ridges 40A, 50A.

[0172] The other end portions 42A, 52A of the second ridges 40A, 50A are tapered from the other ends of the intermediate portions 43A, 53A toward the second input / output terminals 12, and have a uniform width. The width of the intermediate portions 43A and 53A of the second ridges 40A and 50A is constant over the entire length in the Z-axis direction, and the height is constant over the entire length in the Z-axis direction.

[0173] The boundary surface between each of the second ridges 40A and 50A and the inner wall surface of the waveguide 10 is an arc surface that follows the inner wall surface of the waveguide 10 with respect to the YZ plane. The opposing surface of each of the second ridges 40A, 50A facing the boundary surface is rectangular and is a plane that continues from one end 41A, 51A to the middle portion 43A, 53A and the other end 42A, 52A.

[0174] The widths of the one end portions 41A, 51A, the middle portions 43A, 53A, and the other end portions 42A, 52A are the same. The second ridge 40A and the second ridge 50A have the same size and shape. The heights of the second ridges 40A and 50A change gradually when viewed from the first input / output terminal 11 and the second input / output terminal 12, thereby achieving better reflection characteristics.

[0175] From a design parameter perspective, it is preferable that the lateral width of each of the second ridges 40A and 50A be the same as the lateral width of the first input / output ends 21A and 31A and the lateral width of the second input / output ends 22A and 32A of the first ridges 20A and 30A, respectively, but they may be different widths. Furthermore, from a design parameter perspective, it is preferable that the height of the intermediate portions 43A and 53A in the second ridges 40A and 50A, respectively, be the same as the height of the first input / output ends 21A and 31A and the height of the second input / output ends 22A2 and 32A in the first ridges 20A and 30A, respectively, but they may also be different heights. Different widths and heights provide additional design parameters or better axial ratio and reflection characteristics.

[0176] The circular polarizer according to the eighth embodiment is manufactured by die molding in the same manner as the circular polarizer according to the fourth embodiment. The circular optical polarizer according to embodiment 8 may be manufactured using a metal 3D printer with additive manufacturing technology, a resin 3D printer with additive manufacturing technology and metal plating, or resin injection molding and metal plating, as described for the circular optical polarizer according to embodiment 4.

[0177] The circular polarizer according to the eighth embodiment has the same effects as the circular polarizer according to the fourth embodiment. In addition, by tapering one end 41A, 51A and the other end 42A, 52A of each of the second ridges 40A, 50A, the height changes gradually when viewed from each of the first input / output terminal 11 and the second input / output terminal 12. This improves the symmetry of the cross section parallel to the XY plane (first plane) of the waveguide 13, makes it easier to achieve a desired phase difference between two orthogonal linearly polarized signals, and results in better axial ratio characteristics.

[0178] In addition, the intermediate portions 43A, 53A of the pair of second ridges 40A, 50A in the circular polarizer according to embodiment 8 may have the following shapes, similar to those described for the intermediate portions 23, 33 of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4.

[0179] That is, the intermediate portions 43A, 53A in each of the pair of second ridges 40A, 50A are arranged periodically in the tube axis direction of the waveguide 10, similar to the intermediate portions 23, 33 in each of the pair of ridges 20A, 30A in the circular polarizer according to embodiment 4, and each has a plurality of protrusions that protrude in the XY plane (first plane) in a direction along a line connecting the central axes of the pair of first ridges 20A, 30A, and connecting portions that connect adjacent protrusions among the plurality of protrusions.

[0180] Furthermore, in the circular waveguide polarizer according to the eighth embodiment, the pair of first ridges 20A and 30A each have a plurality of protrusions 23a1 to 23a2 at their intermediate portions 23 and 33. N , 33a1~33a N The plurality of protrusions 231a1 to 231a2 at the intermediate portions 231 and 331 of the pair of ridges 201 and 301 in the circular waveguide polarizer according to the second embodiment are respectively N , 331a1-331a N Similarly, the cross section parallel to the third plane (XZ plane) may be trapezoidal.

[0181] Furthermore, the plurality of protrusions 23a1 to 23a2 in the intermediate portions 23 and 33 of the pair of first ridges 20A and 30A in the circular waveguide polarizer according to the eighth embodiment N , 33a1~33a N The plurality of protrusions 232a1 to 232a at the intermediate portions 232, 332 of the pair of ridges 202, 302 in the circular waveguide polarizer according to the third embodiment are N , 332a1-332a N Similarly, the cross section parallel to the XZ plane may be hexagonal.

[0182] It should be noted that the embodiments may be freely combined, or any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted. [Industrial Applicability]

[0183] The circular polarizer according to the present disclosure is primarily applicable to circular polarizers used in the VHF band, UHF band, microwave band, and millimeter wave band, and is suitable for use as a circular polarizer connected to a horn antenna having a circular waveguide terminal. [Explanation of symbols]

[0184] 10 Waveguide, 11 First input / output terminal, 12 Second input / output terminal, 13 Hollow portion, 20, 201 to 203, 30, 301 to 303, 20A, 30A Ridge, 21, 211 to 213, 31, 311 to 313, 21A, 31A First input / output end portion, 22, 221 to 223, 32, 321 to 323, 22A, 32A Second input / output end portion, 23, 231 to 233, 33, 331 to 333 Intermediate portion, 23a1 to 23a N , 231a1-231a N ~233a1~233a N , 33a1~33a N , 331a1-331a N ~333a1~333a N Projection, 23b1~23b N-1 , 231b1-231b N-1 ~233b1~233b N-1 , 33b1~33b N-1, 331b1-331b N-1 ~33b1~333b N-1 Connection, 40, 50, 40A, 50A Second ridge.

Claims

1. A hollow waveguide having a first input / output terminal at one end and a second input / output terminal at the other end, the hollow portion having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; each of the plurality of protrusions has a rectangular cross section parallel to a third plane perpendicular to a second plane including central axes of the pair of ridges; Circularly polarized wave generator.

2. A hollow waveguide having a first input / output terminal at one end and a second input / output terminal at the other end, the hollow portion having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; each of the plurality of protrusions has a trapezoidal cross section parallel to a third plane perpendicular to a second plane including central axes of the pair of ridges; Circularly polarized wave generator.

3. A hollow waveguide having one end as a first input / output terminal and the other end as a second input / output terminal, the hollow waveguide having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; each of the plurality of protrusions has a hexagonal cross section parallel to a third plane perpendicular to a second plane including central axes of the pair of ridges; Circularly polarized wave generator.

4. A hollow waveguide having one end serving as a first input / output terminal and the other end serving as a second input / output terminal, the hollow waveguide having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; the plurality of protrusions have short lengths along a line perpendicular to a line connecting the central axes of the pair of ridges from a central protrusion on the central axis of the ridge toward the first input / output end portion and the second input / output end portion, respectively; Circularly polarized wave generator.

5. 4. The circular polarizer according to claim 1, wherein the plurality of protrusions have short lengths along a line perpendicular to a line connecting the central axes of the pair of ridges from a central protrusion on the central axis of the ridge toward the first input / output end and the second input / output end, respectively.

6. A hollow waveguide having one end serving as a first input / output terminal and the other end serving as a second input / output terminal, the hollow waveguide having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; the lengths of the plurality of protrusions in a direction perpendicular to a line connecting the central axes of the pair of ridges decrease in a trigonometric function pattern from a central protrusion on the central axis of the ridge as an apex toward the first input / output end and the second input / output end; Circularly polarized wave generator.

7. 4. The circular waveguide polarizer according to claim 1, wherein the lengths of the plurality of protrusions in a direction perpendicular to a line connecting the central axes of the pair of ridges decrease in a trigonometric function pattern from a central protrusion on the central axis of the ridge as an apex toward the first input / output end and the second input / output end.

8. A hollow waveguide having one end serving as a first input / output terminal and the other end serving as a second input / output terminal, the hollow waveguide having a circular cross section; a pair of ridges each having a central axis parallel to the axis of the waveguide and disposed opposite to each other on the inner wall surface of the waveguide; each of the pair of ridges has a first input / output end at one end, a second input / output end at the other end, and an intermediate portion between the first input / output end and the second input / output end; the intermediate portion is periodically provided in the tube axis direction of the waveguide, and each intermediate portion has a plurality of protrusions that protrude in a direction along a line orthogonal to a line connecting central axes of the pair of ridges in a first plane perpendicular to the tube axis of the waveguide, and a connecting portion that connects adjacent protrusions among the plurality of protrusions; the plurality of protrusions have a length along the central axis of the ridge that is shorter from a central protrusion along the central axis of the ridge toward the first input / output end and the second input / output end; Circularly polarized wave generator.

9. 4. The circular waveguide polarizer according to claim 1, wherein the plurality of protrusions have a length along the central axis of the ridge that is shorter from a central protrusion on the central axis of the ridge toward the first input / output end and the second input / output end.

10. a first input / output end portion of each of the pair of ridges has a length that is shorter toward the first input / output terminal in a second plane including a central axis of the pair of ridges; a second input / output end portion of each of the pair of ridges has a length that is shorter toward the second input / output terminal in a second plane that includes a central axis of the pair of ridges; 4. The circular polarizer according to claim 1, wherein the circular polarizer is a waveguide.

11. 4. The circular polarizer according to claim 1, further comprising a pair of second ridges, each having a central axis parallel to the tube axis of the waveguide, and arranged opposite each other on the inner wall surface of the waveguide rotated 90 degrees around the tube axis of the waveguide with respect to the pair of ridges.

12. 12. The circular polarizer according to claim 11, wherein each of the pair of second ridges has a uniform length along a line connecting the central axes of the pair of second ridges, and a uniform length along a line perpendicular to the line connecting the central axes of the pair of second ridges.

13. each of the pair of second ridges has one end, another end, and an intermediate portion between the one end and the other end; the intermediate portions of each of the pair of second ridges are periodically arranged in the axial direction of the waveguide, and each of the pair of second ridges has a plurality of protrusions protruding in the first plane in a direction along a line connecting the central axes of the pair of ridges, and a connecting portion connecting adjacent protrusions among the plurality of protrusions; 12. A circular polarizer according to claim 11.

14. each of the pair of second ridges has one end, another end, and an intermediate portion between the one end and the other end; the intermediate portion has a uniform length along a line connecting the central axes of the pair of second ridges over the entire length, and a uniform length along a line perpendicular to the line connecting the central axes of the pair of second ridges, the one end has a length along a line perpendicular to a line connecting the central axes of the pair of second ridges that becomes shorter toward the first input / output terminal, and a length along the line connecting the central axes of the pair of second ridges that is uniform; the other end has a length along a line perpendicular to a line connecting the central axes of the pair of second ridges that becomes shorter toward the second input / output terminal, and a length along the line connecting the central axes of the pair of second ridges that is uniform.

12. A circular polarizer according to claim 11.

15. A method for manufacturing the circular waveguide polarizer according to any one of claims 1 to 3, comprising the steps of: A method for manufacturing a circularly polarized wave generator in which the second input / output terminal is integrally formed toward the first input / output terminal using a 3D printer.

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