Rotary Coupler

Abstract

The rotary coupler is a rotary coupler that uses electromagnetic coupling to transmit and receive signals between a fixed part (10A) and a rotating part (20A) that is rotatably supported on the fixed part (10A). The fixed part (10A) has waveguides (12a, 12b) that have the same diameter, are arc-shaped, and are arranged facing each other about a central axis (O), a lossy medium (11) to which one end of the waveguide (12a) and one end of the waveguide (12b) are connected, and a transmission / reception circuit (13) to which the other end of the waveguide (12a) and the other end of the waveguide (12b) are connected. The rotating part (20A) rotates about a central axis (O) as a center of rotation and has a coupling part (21) that is electromagnetically coupled with at least one of the waveguides (12a, 12b), and a transmitting / receiving circuit (22) that is connected to the coupling part (21) and transmits and receives signals with the transmitting / receiving circuit (13).

Description

[Technical field]

[0001] The present disclosure relates to rotary couplers. [Background technology]

[0002] Conventionally, a rotary coupler has been provided that includes a fixed part and a rotating part that rotates relative to the fixed part. This rotary coupler enables signals to be transmitted and received between the fixed part and the rotating part. For example, Patent Document 1 discloses such a conventional rotary coupler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2008-533786 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotary coupler disclosed in Patent Document 1 includes microstrip lines in both a fixed portion and a rotating portion. The microstrip lines provided in the fixed portion and the microstrip lines provided in the rotating portion have different lengths, are formed in an arc shape, and are arranged opposite each other. The rotary coupler disclosed in Patent Document 1 enables transmission and reception of signals between the two microstrip lines by electromagnetically coupling the microstrip lines of the fixed portion and the microstrip lines of the rotating portion while rotating the rotating portion relative to the fixed portion.

[0005] Here, when the microstrip line of the rotating part passes (rotates) a position facing the terminal end of the microstrip line of the fixed part, the microstrip line of the fixed part corresponding to the microstrip line of the rotating part temporarily disappears. Therefore, the electromagnetic coupling force between the two microstrip lines becomes very small, and the gain decreases. As a result, the rotary coupler disclosed in Patent Document 1 may not be able to transmit and receive signals at all rotation angles of the rotating part.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a rotary coupler that can transmit and receive signals between a fixed part and a rotating part at all rotational angle positions of the rotating part. [Means for solving the problem]

[0007] A rotary coupler according to the present disclosure is a rotary coupler that uses electromagnetic coupling to transmit and receive signals between a fixed part and a rotating part that is rotatably supported relative to the fixed part, Between the fixed section and the rotating section, a first waveguide and a second waveguide are provided, which have the same diameter, are arc-shaped, and are arranged to face each other with a central axis as a center. The fixed section includes a first fixed-side half-waveguide constituting the first waveguide, a second fixed-side half-waveguide constituting the second waveguide, a lossy medium to which one end of the first fixed-side half-waveguide and one end of the second fixed-side half-waveguide are connected, and a fixed-side transmitting / receiving waveguide to which the other end of the first fixed-side half-waveguide and the other end of the second fixed-side half-waveguide are connected. the rotating section has a first rotating-side half-waveguide constituting the first waveguide, a second rotating-side half-waveguide constituting the second waveguide, a coupling section to which one end of the first rotating-side half-waveguide and one end of the second rotating-side half-waveguide are connected and which rotates about a central axis as a rotation center and which electromagnetically couples with at least one of the first fixed-side half-waveguide and the second fixed-side half-waveguide, and a rotating-side transmitting / receiving circuit which is connected to the coupling section and transmits / receives signals to / from the fixed-side transmitting / receiving circuit. It is something. Effect of the Invention

[0008] According to the present disclosure, signals can be transmitted and received between the fixed part and the rotating part at all rotation angle positions of the rotating part. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a rotary coupler according to a first embodiment. [Diagram 2] 2A and 2B are diagrams showing configurations of a fixed section and a rotating section according to embodiment 1. Fig. 2A is a schematic configuration diagram of the fixed section, and Fig. 2B is a schematic configuration diagram of the rotating section. [Diagram 3] 3A and 3B are diagrams illustrating the operation of the rotary coupler according to the first embodiment, in which Fig. 3A illustrates a state in which the coupling portion of the rotary portion does not face the lossy medium of the fixed portion, and Fig. 3B illustrates a state in which the coupling portion of the rotary portion faces the lossy medium of the fixed portion. [Figure 4] 4A and 4B are diagrams showing configurations of a fixed section and a rotating section in a rotary coupler according to embodiment 2. Fig. 4A is a schematic configuration diagram of the fixed section, and Fig. 4B is a schematic configuration diagram of the rotating section. [Diagram 5] FIG. 11 is an exploded perspective view of a rotary coupler according to a third embodiment. [Figure 6] 6A and 6B are diagrams illustrating a configuration of a rotary coupler according to an embodiment 3. Fig. 6A is a plan view of the rotary coupler. Fig. 6B is a cross-sectional view taken along line VI-VI in Fig. 6A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In order to describe the present disclosure in more detail, embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0011] Embodiment 1 The rotary coupler according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0012] First, the configuration of a rotary coupler according to the first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic diagram of the rotary coupler according to the first embodiment. Fig. 2 is a diagram showing the configurations of a fixed section 10A and a rotating section 20A according to the first embodiment.

[0013] 1, the rotary coupler according to the first embodiment includes a fixed part 10A and a rotating part 20A. This rotary coupler transmits and receives signals (e.g., high-frequency signals) between the fixed part 10A and the rotating part 20A by using electromagnetic coupling.

[0014] The fixed part 10A and the rotating part 20A are arranged coaxially and are separated from each other with a predetermined gap in the axial direction. The rotating part 20A rotates around the central axis O (see FIG. 2) of the rotary coupler relative to the fixed part 10A. In FIG. 2B, the arrow surrounding the central axis O indicates the rotation direction of the rotating part 20A. That is, the rotating part 20A can rotate both clockwise and counterclockwise.

[0015] 1 and 2, the fixed part 10A has a lossy medium 11, a first waveguide 12a (hereinafter simply referred to as waveguide 12a), a second waveguide 12b (hereinafter simply referred to as waveguide 12b), and a transmitting / receiving circuit 13. The transmitting / receiving circuit 13 constitutes a fixed-side transmitting / receiving circuit.

[0016] Both the waveguide 12a and the waveguide 12b are arc-shaped and have the same diameter. Furthermore, the waveguide 12a and the waveguide 12b are arranged on the same plane and are coaxial with the central axis O. Therefore, the waveguide 12a and the waveguide 12b are arranged to face each other, and as a whole, they form a substantially circular arc shape.

[0017] One end of the waveguide 12a and one end of the waveguide 12b are connected via a lossy medium 11. Meanwhile, the other end of the waveguide 12a and the other end of the waveguide 12b are connected to a transmitting / receiving circuit 13, respectively.

[0018] 1 and 2, the rotating part 20A has a coupling part 21 and a transmitting / receiving circuit 22. The transmitting / receiving circuit 22 constitutes a rotating-side transmitting / receiving circuit.

[0019] The coupling portion 21 is a transmission line. The coupling portion 21 is arc-shaped and has the same diameter as the diameter D of the waveguides 12a and 12b. The length of the coupling portion 21 is different from the lengths of the waveguides 12a and 12b. Specifically, the length of the coupling portion 21 is shorter than the lengths of the waveguides 12a and 12b. The coupling portion 21 is also arranged coaxially with the central axis O. That is, the waveguides 12a and 12b and the coupling portion 21 are arranged coaxially. Furthermore, the coupling portion 21 is connected to the transmission / reception circuit 22.

[0020] The coupling unit 21 rotates together with the rotation of the rotating unit 20A around the central axis O. At this time, the coupling unit 21 faces at least one of the waveguides 12a and 12b in the axial direction. Therefore, the coupling unit 21 is electrically coupled to at least one of the waveguides 12a and 12b. As a result, signals are transmitted and received between the transmission / reception circuit 13 of the fixed unit 10A and the transmission / reception circuit 22 of the rotating unit 20A.

[0021] Next, the operation of the rotary coupler according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing the operation of the rotary coupler according to the first embodiment. Note that the outlined arrows shown in Figs. 1 and 3 indicate the flow of signals.

[0022] Fig. 3A is a diagram showing a state in which the coupling portion 21 of the rotating portion 20A does not face the lossy medium 11 of the fixed portion 10A. As shown in Fig. 3A, when the coupling portion 21 of the rotating portion 20A does not face the lossy medium 11 of the fixed portion 10A (in other words, when the coupling portion 21 is disposed offset with respect to the lossy medium 11), a signal output from the transmission / reception circuit 13 of the fixed portion 10A is in phase with the other end of the waveguide 12a and the other end of the waveguide 12b and is distributed into two.

[0023] The signal distributed to the other end of waveguide 12a is transmitted along the length of waveguide 12a and then absorbed by lossy medium 11. On the other hand, the signal distributed to the other end of waveguide 12b is transmitted along the length of waveguide 12b and then reaches coupling section 21. Therefore, the signal that reaches coupling section 21 is electromagnetically coupled with coupling section 21 and transmitted to transmission / reception circuit 22. Such a signal that travels from transmission / reception circuit 13, through waveguide 12b, passing through coupling section 21, and reaching transmission / reception circuit 22 is transmitted without discontinuity in the electromagnetic field distribution and as a wideband signal.

[0024] Fig. 3B is a diagram showing a state in which the coupling portion 21 of the rotating portion 20A faces the lossy medium 11 of the fixed portion 10A. As shown in Fig. 3B, when the coupling portion 21 of the rotating portion 20A faces the lossy medium 11 of the fixed portion 10A (in other words, when the coupling portion 21 is located directly above the lossy medium 11), a signal output from the transmission / reception circuit 13 of the fixed portion 10A is in phase with the other end of the waveguide 12a and the other end of the waveguide 12b and is distributed into two.

[0025] The signal distributed to the other end of waveguide 12a is transmitted along the length of waveguide 12a and then reaches coupling portion 21. On the other hand, the signal distributed to the other end of waveguide 12b is transmitted along the length of waveguide 12b and then reaches coupling portion 21.

[0026] Here, when the length of the waveguide 12a and the length of the waveguide 12b are the same, or when the difference between the length of the waveguide 12a and the length of the waveguide 12b is an integer multiple of the wavelength of the signal, the signal transmitted from the waveguide 12a and the signal transmitted from the waveguide 12b are combined in phase because the waveguides 12a and 12b are electromagnetically coupled to the coupling unit 21. The combined signal is then transmitted to the transmitting / receiving circuit 22. Such a signal that travels from the transmitting / receiving circuit 13 through the waveguides 12a and 12b, the coupling unit 21, and the transmitting / receiving circuit 22 is transmitted as a wideband signal without discontinuity in the electromagnetic field distribution.

[0027] In the operation of the rotary coupler described above, the operation of receiving a signal transmitted from the transmission / reception circuit 13 of the fixed part 10A by the transmission / reception circuit 22 of the rotating part 20A has been described. However, since this explanation provides a sufficient understanding of the operation of receiving a signal transmitted from the transmission / reception circuit 22 of the rotating part 20A by the transmission / reception circuit 13 of the fixed part 10A, a description of this operation will be omitted.

[0028] Therefore, the rotary coupler according to the first embodiment does not cause discontinuity in the electromagnetic field distribution when coupling unit 21 is disposed at a rotation angle position other than directly above lossy medium 11. Furthermore, when coupling unit 21 is disposed at a rotation angle position corresponding to directly above lossy medium 11, the rotary coupler according to the first embodiment combines signals from both waveguides 12a, 12b and coupling unit 21 in phase due to electromagnetic coupling between them. Therefore, the rotary coupler according to the first embodiment can transmit and receive signals between fixed unit 10A and rotating unit 20A regardless of the rotation angle position of rotating unit 20A.

[0029] As described above, the rotary coupler according to the first embodiment is a rotary coupler that uses electromagnetic coupling to transmit and receive signals between the fixed part 10A and the rotating part 20A that is rotatably supported by the fixed part 10A. The fixed part 10A has the waveguides 12a and 12b that have the same diameter, are arc-shaped, and are arranged facing each other about the central axis O, a lossy medium 11 to which one end of the waveguide 12a and one end of the waveguide 12b are connected, and a transmission / reception circuit 13 to which the other end of the waveguide 12a and the other end of the waveguide 12b are connected. The rotating part 20A rotates about the central axis O as a rotation center, and has a coupling part 21 that electromagnetically couples with at least one of the waveguides 12a and 12b, and a transmission / reception circuit 22 that is connected to the coupling part 21 and transmits and receives signals between the coupling part 21 and the transmission / reception circuit 13. Therefore, the rotary coupler according to the first embodiment can transmit and receive signals between the fixed portion 10A and the rotating portion 20A at all rotational angle positions of the rotating portion 20A.

[0030] Embodiment 2 A rotary coupler according to the second embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing the configuration of a fixed section 10B and a rotating section 20A in the rotary coupler according to the second embodiment. Note that the same reference numerals are used for configurations having the same functions as those described in the first embodiment above, and the description thereof will be omitted.

[0031] As shown in Fig. 4, the rotary coupler according to the second embodiment includes a fixed portion 10B and a rotating portion 20A. This rotary coupler transmits and receives signals between the fixed portion 10B and the rotating portion 20A by using electromagnetic coupling. That is, the rotary coupler according to the second embodiment has a structure including a fixed portion 10B instead of the fixed portion 10A of the rotary coupler according to the first embodiment.

[0032] As shown in FIG. 4A, the fixed portion 10B includes a lossy medium 11, a waveguide 12a, a waveguide 12b, a branch portion 12c, and a transmitting / receiving circuit 13.

[0033] Fixed portion 10B assumes that waveguide 12a, waveguide 12b, and branch portion 12c are microstrip lines, and lossy medium 11 is a terminator. For this reason, the rotary coupler can easily manufacture waveguide 12a, waveguide 12b, and branch portion 12c. Furthermore, by using lossy medium 11 as a terminator, the rotary coupler can prevent unnecessary reflection of signals at the ends of the microstrip lines (the tips of waveguide 12a and waveguide 12b).

[0034] Branch portion 12c is formed in a T-shape or a bifurcated shape. A base end of branch portion 12c is connected to transmission / reception circuit 13. Two tips of branch portion 12c are connected to the other end of waveguide 12a and the other end of waveguide 12b, respectively.

[0035] As shown in Fig. 4B, the rotating part 20A has a coupling part 21 and a transmitting / receiving circuit 22. In the rotary coupler according to the second embodiment, the coupling part 21 is assumed to be a probe using a microstrip line. In this case, the position of the probe is disposed on the rotation radius (diameter dimension D) of the lossy medium 11, the waveguide 12a, the waveguide 12b, and the branch part 12c. In this case, the rotary coupler is capable of adjusting the position of the probe as appropriate within a range in which a desired amount of electromagnetic coupling can be obtained.

[0036] The transmission line used in the probe may be a line form other than a microstrip line. It is preferable that the transmission line used in the probe does not resonate at the frequency used. For example, if the transmission line has a linear shape, the length of the transmission line may be set to be equal to λ / 2.

[0037] Therefore, the rotary coupler according to the second embodiment does not cause discontinuity in the electromagnetic field distribution when coupling unit 21 is disposed at a rotation angle position other than directly above lossy medium 11. Furthermore, when coupling unit 21 is disposed at a rotation angle position corresponding to directly above lossy medium 11, the rotary coupler according to the second embodiment combines signals from both waveguides 12a, 12b and coupling unit 21 in phase due to electromagnetic coupling between them. Therefore, the rotary coupler according to the second embodiment can transmit and receive signals between fixed unit 10B and rotating unit 20A regardless of the rotation angle position of rotating unit 20A.

[0038] As described above, the rotary coupler according to the second embodiment is a rotary coupler that uses electromagnetic coupling to transmit and receive signals between the fixed part 10B and the rotating part 20A that is rotatably supported by the fixed part 10B. The fixed part 10B has the waveguides 12a and 12b that have the same diameter, are arc-shaped, and are arranged facing each other about the central axis O, a lossy medium 11 to which one end of the waveguide 12a and one end of the waveguide 12b are connected, and a transmission / reception circuit 13 to which the other end of the waveguide 12a and the other end of the waveguide 12b are connected. The rotating part 20A rotates about the central axis O as a rotation center, and has a coupling part 21 that electromagnetically couples with at least one of the waveguides 12a and 12b, and a transmission / reception circuit 22 that is connected to the coupling part 21 and transmits and receives signals between the transmission / reception circuit 13. Therefore, the rotary coupler according to the second embodiment can transmit and receive signals between fixed portion 10B and rotating portion 20A at all rotational angle positions of rotating portion 20A.

[0039] Embodiment 3 A rotary coupler according to the third embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is an exploded perspective view of the rotary coupler according to the third embodiment. Fig. 6 is a diagram showing the configuration of the rotary coupler according to the third embodiment. Note that components having the same functions as those described in the first embodiment above are given the same reference numerals, and the description thereof will be omitted.

[0040] 5 and 6, the rotary coupler according to the third embodiment includes a fixed portion 10C and a rotating portion 20C. This rotary coupler transmits and receives signals between the fixed portion 10C and the rotating portion 20C by using electromagnetic coupling.

[0041] The fixed section 10C has a lossy medium 11, a first fixed-side half waveguide 121 (hereinafter simply referred to as the fixed-side half waveguide 121) of the waveguide 12a, a second fixed-side half waveguide 123 (hereinafter simply referred to as the fixed-side half waveguide 123) of the waveguide 12b, and a transmitting / receiving circuit 13. In the fixed section 10C, the lossy medium 11 is assumed to be a radio wave absorber.

[0042] In contrast, the rotating section 20C has a coupling section 21, a transmitting / receiving circuit 22, a first rotating-side half waveguide 122 of the waveguide 12a (hereinafter simply referred to as the rotating-side half waveguide 122), and a second rotating-side half waveguide 124 of the waveguide 12b (hereinafter simply referred to as the rotating-side half waveguide 124).

[0043] That is, the waveguide 12a has a half structure (or a divided structure) in the axial direction, with the boundary between the fixed part 10C and the rotating part 20C. The waveguide 12a is divided into a fixed-side half waveguide 121 and a rotating-side half waveguide 122. The fixed-side half waveguide 121 and the rotating-side half waveguide 122 are both groove-shaped, and are arranged so that their openings face each other in the axial direction. Therefore, a hollow portion that serves as a waveguide is formed between them.

[0044] On the other hand, the waveguide 12b has a half structure (or a divided structure) in the axial direction, with the boundary between the fixed part 10C and the rotating part 20C. This waveguide 12b is divided into a fixed-side half waveguide 123 and a rotating-side half waveguide 124. Both the fixed-side half waveguide 123 and the rotating-side half waveguide 124 have a groove shape, and are arranged so that their openings face each other in the axial direction. Therefore, a hollow part that serves as a waveguide is formed between them.

[0045] One end of the fixed-side half-waveguide 121 and one end of the fixed-side half-waveguide 123 are connected via a lossy medium 11. The other end of the fixed-side half-waveguide 121 and the other end of the fixed-side half-waveguide 123 are each connected to the transmission / reception circuit 13. Note that the other end of the fixed-side half-waveguide 121 and the other end of the fixed-side half-waveguide 123 may be connected to the transmission / reception circuit 13 via a branch portion 12c.

[0046] Moreover, one end of the rotation-side half-waveguide 122 and one end of the rotation-side half-waveguide 124 are connected via a coupling portion 21. The other end of the fixed-side half-waveguide 121 and the other end of the fixed-side half-waveguide 123 are connected to each other.

[0047] Therefore, the rotary coupler according to the third embodiment does not cause discontinuity in the electromagnetic field distribution when coupling unit 21 is disposed at a rotation angle position other than directly above lossy medium 11. Furthermore, when coupling unit 21 is disposed at a rotation angle position corresponding to directly above lossy medium 11, the rotary coupler according to the third embodiment combines signals from both waveguides 12a, 12b and coupling unit 21 in phase due to electromagnetic coupling between them. Therefore, the rotary coupler according to the third embodiment can transmit and receive signals between fixed unit 10C and rotating unit 20C regardless of the rotation angle position of rotating unit 20C.

[0048] As described above, the rotary coupler according to the third embodiment is a rotary coupler that uses electromagnetic coupling to transmit and receive signals between a fixed portion 10C and a rotating portion 20C that is rotatably supported by the fixed portion 10C. Between the fixed portion 10C and the rotating portion 20C, two waveguides 12a and 12b are arranged with a central axis O as a center, and have the same diameter and an arc shape, facing each other. 12b The fixed section 10C has a fixed-side half-split waveguide 121 constituting the waveguide 12a, a fixed-side half-split waveguide 123 constituting the waveguide 12b, a lossy medium 11 to which one end of the fixed-side half-split waveguide 121 and one end of the fixed-side half-split waveguide 123 are connected, and a transmission / reception circuit 13 to which the other end of the fixed-side half-split waveguide 121 and the other end of the fixed-side half-split waveguide 123 are connected. The rotating unit 20C includes a rotating-side half-waveguide 122 constituting the waveguide 12a, a rotating-side half-waveguide 124 constituting the waveguide 12b, a coupling unit 21 to which one end of the rotating-side half-waveguide 122 and one end of the rotating-side half-waveguide 124 are connected and which rotates about a central axis O as a rotation center and which electromagnetically couples with at least one of the fixed-side half-waveguide 121 and the fixed-side half-waveguide 123, and a transmitting / receiving circuit 22 connected to the coupling unit 21 and which transmits and receives signals with the transmitting / receiving circuit 13. For this reason, the rotary coupler according to the third embodiment can transmit and receive signals between the fixed unit 10C and the rotating unit 20C at all rotation angle positions of the rotating unit 20C.

[0049] In addition, within the scope of the present disclosure, 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]

[0050] The rotary coupler according to the present disclosure is suitable for use in rotary couplers and the like because it is possible to transmit and receive signals between the fixed part and the rotating part at all rotational angle positions of the rotating part by providing a lossy medium in the fixed part. [Explanation of symbols]

[0051] 10A, 10B, 10C fixed portion, 11 lossy medium, 12a first waveguide, 121 first fixed side half waveguide, 122 first rotating side half waveguide, 12b second waveguide, 123 second fixed side half waveguide, 124 second rotating side half waveguide, 12c branching portion, 13 transmitting / receiving circuit, 20A, 20C rotating portion, 21 coupling portion, 22 transmitting / receiving circuit, D diameter dimension, O central axis.

Claims

1. A rotary coupler that uses electromagnetic coupling to transmit and receive signals between a fixed part and a rotating part that is rotatably supported relative to the fixed part, a first waveguide and a second waveguide having a split structure, the first waveguide and the second waveguide having the same diameter, being arc-shaped, and being disposed about a central axis so as to face each other, between the fixed portion and the rotating portion; The fixing portion is a first fixed half-waveguide constituting the first waveguide; a second fixed half-waveguide constituting the second waveguide; a lossy medium to which one end of the first fixed half-waveguide and one end of the second fixed half-waveguide are connected; a fixed-side transmitting / receiving circuit to which the other end of the first fixed-side half-waveguide and the other end of the second fixed-side half-waveguide are connected, The rotating part is a first rotating half-waveguide constituting the first waveguide; a second rotating half-waveguide constituting the second waveguide; a coupling section that connects one end of the first rotating-side half-waveguide and one end of the second rotating-side half-waveguide, rotates about the central axis, and electromagnetically couples with at least one of the first fixed-side half-waveguide and the second fixed-side half-waveguide; a rotation-side transmitting / receiving circuit connected to the coupling portion and transmitting / receiving signals to / from the fixed-side transmitting / receiving circuit; 1. A rotary coupler comprising:

2. The length of the first waveguide and the length of the second waveguide are the same.

2. The rotary coupler of claim 1.

3. The difference between the length of the first waveguide and the length of the second waveguide is an integer multiple of the wavelength of the signal.

2. The rotary coupler of claim 1.

4. The first waveguide and the second waveguide are microstrip lines.

4. A rotary coupler according to claim 2 or 3.

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