Mode converter and antenna having a mode converter

Abstract

The objective is to provide a wideband mode converter that can convert an input in TE10 mode, used in rectangular waveguides, etc., to an output in TM01 mode, used in circular waveguides, etc. [Solution] The mode converter includes an input unit, a first rectangular output unit, and a second rectangular output unit, and comprises an inverse phase conversion unit that converts the TE10 mode electromagnetic wave input to the input unit into two electromagnetic waves with a phase difference of 180° from each other and outputs them to the first rectangular output unit and the second rectangular output unit, a first semicircular output unit connected to the first rectangular output unit and equipped with a first semicircular output unit, a second semicircular output unit connected to the second rectangular output unit and equipped with a second semicircular output unit, and a TM01 mode generation unit connected to the first semicircular output unit and the second semicircular output unit that generates the TM01 mode and outputs it to the circular output unit.

Description

Technical Field

[0001] The present invention relates to a waveguide mode converter suitable for high frequencies of 110 GHz or higher, a mode converter, and an antenna having this mode converter. Further, the present invention particularly relates to a waveguide mode converter that converts a TE10 mode to a TM01 mode or vice versa, and an antenna having this mode converter.

Background Art

[0002] In wireless communication, the development of antennas using the sub-terahertz band is underway. Among these, an omnidirectional antenna can communicate in all directions of 360 degrees. An omnidirectional antenna can be configured by using the TM01 mode. A 300 GHz band reflector omnidirectional antenna using a TM01 mode converter is known (Non-Patent Document 1). Also, a technique for converting electromagnetic waves from the TE10 mode, which is the basic mode of transmission in a waveguide, to the TM01 mode is known (Patent Documents 1 to 3). Patent Document 4 describes an antenna having a receiving unit that receives TE10 electromagnetic waves, a first conversion unit that is connected to the receiving unit and converts the TE10 mode to the TE20 mode in the waveguide, and a second conversion unit that is connected to the first conversion unit and converts the TE20 mode to the TE01 mode in the waveguide.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Patent Documents

[0004] [Patent Document 1] International Publication No. 2005-41344 [Patent Document 2] Patent No. 5749841 [Patent Document 3] Patent No. 5816768 [Patent Document 4] Patent application No. 2024-002205 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] For wideband antennas and similar devices, a wideband mode converter is also required. Mode converters that convert from TE10 mode to TM01 mode, as described in Patent Documents 1-3, utilize a resonant structure. In other words, when the propagation path is bent perpendicularly, electromagnetic waves at the resonant frequency are efficiently converted from TE10 mode to TM01 mode. However, this structure cannot achieve a wide bandwidth, and as a result, even when used in antennas, the antenna becomes narrow-band. Patent Document 4 describes an antenna having a rectangular T-shaped conversion unit that changes the cross-section of the waveguide from a TE10 rectangle to a T-shape, and a T-shaped rectangular conversion unit connected to the rectangular T-shaped conversion unit that changes the cross-section of the waveguide from a T-shape to a TE20 rectangle, and a second conversion unit having a TE20 tapered conversion unit that converts the aspect ratio of the TE20 rectangle, and a TE20TE01 conversion unit connected to the TE20 tapered conversion unit that changes the cross-section of the waveguide from a TE20 rectangle to a TE01 circle, but the output is in TE01 mode. Therefore, the present invention aims to provide a broadband mode converter that converts an input in TE10 mode, used in rectangular waveguides, etc., to an output in TM01 mode, used in circular waveguides, etc., or vice versa. Furthermore, the aim is to provide a wideband vertical polarization omnidirectional antenna equipped with a TE10-TM01 mode converter capable of operating in this wideband range. Other objects of the present invention will also be described in the embodiments for carrying out the invention. [Means for solving the problem]

[0006] The mode converter according to claim 1 of the present invention is The unit comprises an input section, a first rectangular output section, and a second rectangular output section. The inverse phase conversion section converts the TE10 mode electromagnetic wave input to the input section into two electromagnetic waves with a phase difference of 180° from each other, and outputs them to the first rectangular output section and the second rectangular output section. A first semicircular output section connected to a first rectangular output section and comprising a first semicircular output section, A second semicircular output unit connected to a second rectangular output unit and comprising a second semicircular output unit, and This mode converter includes a TM01 mode generation unit connected to a first semicircular output unit and a second semicircular output unit, which generates the TM01 mode. The mode converter according to claim 2 of the present invention is The inverse phase conversion unit has a T-shaped conversion unit. The T-shaped conversion unit is a mode converter according to claim 1, which converts from TE10 mode to TE20 mode. The mode converter according to claim 3 of the present invention is A splitting unit that divides the TE20 mode electromagnetic wave generated in the T-shaped conversion unit into two electromagnetic waves with a phase difference of 180 degrees from each other. The mode converter according to claim 2, having a first divided output unit that connects one of the two electromagnetic waves divided in the divided unit to a first semicircular output unit, and a second divided output unit that connects the other of the two electromagnetic waves to a second semicircular output unit. The mode converter according to claim 4 of the present invention is the mode converter according to claim 3, wherein the first divided output unit and the second divided output unit each include a first directional moving unit that moves parallel to either the long side or the short side of the input unit in a cross section perpendicular to the direction of propagation of electromagnetic waves, and a second directional moving unit that moves parallel to the other of the long side or the short side of the input unit. The mode converter according to claim 5 of the present invention is The inverse phase conversion section is, A phase distribution unit connected to the input unit distributes the signal to a first phase unit and a second phase unit, which are in the same phase. It has a 180-degree phase shifter connected to the second in-phase part, The first in-phase part is connected to the first rectangular output part, and the 180-degree phase shifter is connected to the second rectangular output part. The mode converter according to claim 1. The mode converter according to claim 6 of the present invention is the mode converter according to any one of claims 1 to 5, wherein the inverse phase conversion part does not have a resonance structure. The mode converter according to claim 7 of the present invention is the mode converter according to any one of claims 1 to 5, wherein the inverse phase conversion part has a symmetric structure for converting into two electromagnetic waves. The mode converter according to claim 8 of the present invention is the mode converter according to any one of claims 1 to 5, wherein the specific bandwidth is 13% or more. The mode converter according to claim 9 of the present invention is the mode converter according to any one of claims 1 to 5, wherein the frequency of the electromagnetic wave is 110 GHz or more. The antenna according to claim 10 of the present invention An antenna having the mode converter according to any one of claims 1 to 5, Comprising a conical reflector, The conical reflector is arranged such that the axis of the cone is coaxial with the axis of the TM01 mode generating part, An antenna that emits electromagnetic waves in a direction perpendicular to the axis of the cone. With the above configuration, the present invention can convert the input of the TE10 mode used in a rectangular waveguide or the like into the output of the TM01 mode used in a circular waveguide or the like. Further, a broadband vertically polarized omnidirectional antenna using this mode converter can be realized. Other effects of the present invention will also be described in the mode for carrying out the invention.

Brief Description of the Drawings

[0007] [Figure 1] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 2] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 3] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 4] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 5] Shows an example of the specific bandwidth of a mode converter in an embodiment of the present invention. [Figure 6] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 7] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 8] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 9] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 10] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 11] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 12] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 13] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 14] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 15] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 16] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 17] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 18] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 19] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 20] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 21] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 22] Shows a configuration example of a mode converter in an embodiment of the present invention. [Figure 23] An example of the relative bandwidth of a mode converter in one embodiment of the present invention is shown. [Figure 24] An example of the relative bandwidth of a mode converter in one embodiment of the present invention is shown. [Figure 25] This shows an example of the configuration of a mode converter in one embodiment of the present invention. [Figure 26] This shows an example of the antenna configuration in one embodiment of the present invention. [Figure 27] This shows an example of the antenna configuration in one embodiment of the present invention. [Figure 28] This shows an example of the antenna configuration in one embodiment of the present invention. [Modes for carrying out the invention]

[0008] Figures 1 and 2 show an example configuration of the mode converter 3 in one embodiment of the present invention. In Figure 2, the electromagnetic wave modes are indicated for each part for ease of understanding, but the configuration is the same as in Figure 1. Similarly, in the following figures, the electromagnetic wave modes for each part may also be indicated. In this embodiment, the mode converter 3 comprises an inverse phase conversion unit 4, a first semicircular output unit 51, a second semicircular output unit 52, and a TM01 mode generation unit 6.

[0009] The inverse phase conversion unit 4 has an input unit 40 such as a rectangular waveguide, a first rectangular output unit 48, and a second rectangular output unit 49. The inverse phase conversion unit 4 converts the TE10 mode electromagnetic wave input to the input unit 40 into two electromagnetic waves with a phase difference of 180° from each other, and outputs them to the first rectangular output unit 48 such as a rectangular waveguide and the second rectangular output unit 49 such as a rectangular waveguide. In this specification and claims, electromagnetic waves in TE10 mode may be simply referred to as TE10 mode. The same applies to TE20 mode, TM01 mode, etc.

[0010] The first rectangular output unit 48 is connected to the first semicircular output unit 51. The second rectangular output section 49 is connected to the second semicircular output section 52. The TM01 mode generation unit 6 is connected to the first semicircular output unit 51 and the second semicircular output unit 52 to generate the TM01 mode, which in this embodiment is output to a circular output unit such as a circular waveguide.

[0011] In this embodiment, the device is described as a mode converter that converts TE10 mode to TM01 mode. However, if TM01 mode is input from the TM01 mode generation unit 6, it is converted to TE10 mode at the input unit 40. In other words, it can also be used as a mode converter that converts TM01 mode to TE10 mode. Naturally, such a configuration is also included in this configuration. Furthermore, by utilizing bidirectional conversion, a transmitting and receiving antenna as described later can also be constructed.

[0012] Figures 3 and 4 show an example of the configuration of the mode converter 3 in one embodiment of the present invention. In this embodiment, the inverse phase conversion unit 4 in the mode converter 3 includes an in-phase distribution unit 44 and a 180-degree phase shift unit 45.

[0013] The in-phase distribution unit 44 is connected to the input unit 40 and distributes to the first in-phase unit 441 and the second in-phase unit 442. The 180-degree phase shift unit 45 is connected to the second in-phase distribution unit 442 and shifts the electromagnetic wave phase by 180 degrees.

[0014] The first in-phase unit 441 is connected to the first rectangular output unit 48, and the 180-degree phase shift unit 45 is connected to the second rectangular output unit 49. In this embodiment, the input unit 40 receives the TE10 mode of the waveguide fundamental mode, which is a rectangular waveguide. The TE10 mode from the input unit 40 is distributed vertically. After distribution, the signals are in phase.

[0015] After distribution, one of the electromagnetic waves is phase-shifted by 180 degrees by the 180-degree phase-shift unit 45 loaded on the second in-phase unit 442. Two rectangular waveguides with reversed phase shifts undergo a rectangular-to-semicircular transformation. The two semicircular waveguides combine to form a circular waveguide, generating the TM01 mode.

[0016] Figure 5 is a graph showing an example of the relative bandwidth of the mode converter 3 described above. The horizontal axis of the graph represents frequency in GHz, and the vertical axis represents the mode conversion efficiency between the TE10 mode and the TM01 mode in %. In this embodiment, the mode converter 3 has a relative bandwidth of 13% or more. Here, the relative bandwidth is the value obtained by dividing the frequency range in which the signal strength at the center frequency is 90% or more by the center frequency. In the example shown in the figure, it is approximately 14%, obtained by dividing approximately 42 GHz from approximately 273 GHz to approximately 315 GHz by the center frequency of approximately 293 GHz.

[0017] In the configuration using the 180-degree phase shifter described above, when used with antenna 1, the axis of the omnidirectional antenna may shift to one direction. The following describes a configuration that solves this problem. Figures 6 and 7 show an example of the configuration of the mode converter 3 in one embodiment of the present invention. In this embodiment, the inverse phase conversion unit 4 in the mode converter 3 has a T-shaped conversion unit 41.

[0018] The T-shaped conversion unit 41 has a structure that converts from TE10 mode to TE20 mode. In the configuration using the 180-degree phase shift unit described above, a difference in electric field strength occurred in the distribution ratio between the two paths because the 180-degree phase shift unit was provided in only one path. However, with this configuration, since the 180-degree phase shift unit is not provided in only one path, this problem is not expected to occur.

[0019] Figures 8 and 9 show an example of the configuration of the mode converter 3 in one embodiment of the present invention. In this embodiment, the mode converter 3 has a splitting unit 43, a first splitting output unit 431, and a first splitting output unit 431.

[0020] The splitting unit 43 splits the TE20 mode electromagnetic wave generated in the T-shaped conversion unit 41 into two electromagnetic waves with a phase difference of 180 degrees from each other. The first divided output unit 431 connects one of the two electromagnetic waves divided by the dividing unit 43 to the first semicircular output unit 51. The second divided output unit 432 connects the other of the two electromagnetic waves divided by the dividing unit 43 to the second semicircular output unit 52.

[0021] In this embodiment, the TE10 mode input of a rectangular waveguide in the fundamental mode is converted from TE10 to TE20 using a T-shaped converter. The TE20 mode is split and moved vertically and horizontally respectively, and the two rectangular waveguides, which are now in opposite phase, are converted from rectangular to semicircular. Then, the two semicircular waveguides are combined to form a circular waveguide, generating the TM01 mode.

[0022] Figures 10 to 14 show an example of the configuration of the mode converter 3 in one embodiment of the present invention. Figures 11 to 14 sequentially show the changes in the position of the cross-sectional view for ease of understanding, and it should be noted that the outer rectangles in the figures are for illustrating the changes in the cross-section and are not actual components. The same applies to Figures 15 to 22. As shown in Figure 10, in this embodiment, the first divided output section 431 and the second divided output section 432 of the mode converter 3 include first directional moving sections 4311, 4321 that move parallel to either the long side or the short side of the input section 40 in a cross section perpendicular to the direction of propagation of electromagnetic waves, and second directional moving sections 4312, 4322 that move parallel to the other of the long side or the short side of the input section 40.

[0023] Specifically, as shown in Figure 12, one of the two electromagnetic waves with a 180-degree phase difference, shown in the left half of the unfolded section 42, first moves to the left, then moves upward as shown in Figure 13, and finally moves to the right as shown in Figure 14, thereby moving to the upper right half of the unfolded section 42 and connecting to the first rectangular output section 48. The cross-section of the right half of the unfolded section 42 does not move; that is, the other electromagnetic wave travels in a straight line and connects to the second rectangular output section 49. This configuration eliminates the need for a complex shape, resulting in a low-cost, high-precision mode converter 3.

[0024] Figures 15 to 18 show an example of the configuration of the mode converter 3 in one embodiment of the present invention. In this embodiment, first, one of the two electromagnetic waves with a 180-degree phase difference, shown in the left half of the diagram of the unfolding section 42, moves to the left, and the right half of the diagram moves to the right. Next, the left half moves upward, and the right half moves downward. Finally, as the left half of the diagram moves to the right and the right half moves to the left, the other of the two electromagnetic waves with a 180-degree phase difference, shown in the right half of the unfolding section 42, moves upward, and the left half of the unfolding section 42 moves downward, connecting to the first rectangular output section 48 and the second rectangular output section 49, respectively. This configuration also eliminates the need for a complex shape, resulting in a low-cost, high-precision mode converter 3.

[0025] In one embodiment of the present invention, the mode converter 3 and the inverse phase conversion unit 4 do not have a resonant structure. That is, in a resonant structure, as described in Patent Documents 1 to 3, when the propagation path is bent perpendicularly, electromagnetic waves at the resonant frequency are efficiently converted from TE10 mode to TM01 mode. In contrast, this embodiment does not have such a resonant structure. This configuration provides broadband characteristics that allow operation across a wide frequency range, rather than narrowband characteristics that only operate at specific frequencies.

[0026] Figures 19 to 22 show an example configuration of the mode converter 3 in one embodiment of the present invention. In this embodiment, the inverse phase conversion unit 4 in the mode converter 3 has a symmetrical structure that converts into two electromagnetic waves. In this embodiment, first, one of the two electromagnetic waves with a 180-degree phase difference, shown in the left half of the diagram of the unfolded section 42, moves to the left, and the other of the two electromagnetic waves with a 180-degree phase difference, shown in the right half of the diagram, moves to the right.

[0027] Next, the left half moves upward, and the right half moves downward. In this configuration as well, the transformations between the two electromagnetic waves are symmetrical. Finally, as the left half moves to the right and the right half moves to the left, the right half of the unfolding section 42 moves to the upper side and the left half of the unfolding section 42 moves to the lower side, connecting to the first rectangular output section 48 and the second rectangular output section 49, respectively. In this configuration as well, the conversion of the two electromagnetic waves is symmetrical. With the above configuration, there is no difference in intensity between the two electromagnetic waves, and the combined TM01 mode also has stable directivity with respect to the radiation axis.

[0028] Figures 23 and 24 are graphs showing examples of the relative bandwidth of the mode converter 3 described above. In both graphs, the horizontal axis represents frequency in GHz, and the vertical axis represents the mode conversion efficiency between the TE10 mode and the TM01 mode in %. In this embodiment, the mode converter 3 has a relative bandwidth of 13% or more. Here, the relative bandwidth is the value obtained by dividing the frequency range in which the signal strength at the center frequency is 90% or more by the center frequency, and in the example shown in the figure, it is 15% or more.

[0029] In one embodiment of the present invention, the mode converter 3 has an electromagnetic wave frequency of 110 GHz or higher. In this embodiment, the WR3 standard from 220 GHz to 330 GHz is shown, but other standard bands such as the WR6 standard from 110 GHz to 170 GHz are also possible.

[0030] Figure 25 shows an example of the configuration of antenna 1 in one embodiment of the present invention. In this embodiment, antenna 1 is an antenna having any of the above-described mode converters 3 and includes a conical reflector 8. Here, the conical reflector 8 includes not only cones but also shapes similar to cones, such as parabolic shapes. In other words, the conical reflector 8 has a convex side on the mode converter 3 side, and the side opposite the mode converter 3 is approximately circular or approximately regular polygonal, and by widening from the convex side on the mode converter 3 side, it is possible to diffuse the electromagnetic waves from the mode converter 3 in a 360-degree direction.

[0031] The conical reflector 8 is positioned such that the axis of the cone is coaxial with the axis of the TM01 mode generation unit. Antenna 1 emits electromagnetic waves in a direction perpendicular to the axis of the cone. This allows it to be configured as a vertically polarized omnidirectional antenna. Here, "direction perpendicular to the axis of the cone" refers to the direction radiating from the axis of the cone, and also includes a range of about 30° from the axis perfectly perpendicular to the axis of the cone. Furthermore, this includes not only a configuration that constantly transmits and receives electromagnetic waves in a 360° direction as an omnidirectional antenna, but also a configuration that transmits or receives electromagnetic waves in a 360° direction at a predetermined period, or substantially.

[0032] In this embodiment, the conical reflector 8 is conical in shape, but includes configurations such as one in which the cross-section is part of a parabola as shown in Figure 26, or one in which the side of the conical reflector 8 facing the mode converter 3 is convex and the side opposite to the mode converter 3 is a roughly regular polygon as shown in Figure 27. Figure 26 shows a cross-section of a conical reflector 8 in one embodiment of the present invention. In this embodiment, the cross-section of the conical reflector 8 forms part of a parabola. For ease of understanding, the figure shows x and y axes and extends the parabola, but it should be noted that the part of the parabola that constitutes the conical reflector 8, other than the portion, does not represent the actual configuration. Figure 27 shows a cross-section of a conical reflector 8 in one embodiment of the present invention. The figure shows the conical reflector 8 as viewed from the mode converter 3 side. In this embodiment, the side of the conical reflector 8 facing the mode converter 3 is convex, and the side opposite the mode converter 3 is a regular decagon, which is a roughly regular polygon.

[0033] Here, the omnidirectional antenna 1 also includes an antenna 1 that radiates electromagnetic waves in a 360° direction by periodically rotating in a predetermined direction. Figure 28 shows a conical reflector 8 of the antenna 1 in one embodiment of the present invention. The figure shows the conical reflector 8 as viewed from the mode converter 3 side. In this embodiment, the conical reflector 8 has a fan-shaped rotating reflector 81, and the fan-shaped rotating reflector 81 reflects electromagnetic waves.

[0034] The electromagnetic waves emitted by the mode converter 3 are reflected by the fan-shaped rotating reflector 81 and radiated in the desired direction. Alternatively, the electromagnetic waves reflected by the fan-shaped rotating reflector 81 are input to the mode converter 3 and converted to TE01 mode. In this configuration, the direction of arrival of the electromagnetic waves can be detected by the position of the fan-shaped rotating reflector 81.

[0035] The present invention is not limited to the embodiments described above, and it goes without saying that it includes various embodiments without departing from the spirit of the invention. For example, configurations that not only convert TE10 mode to TM01 mode, but also the reverse, or both, are naturally included. [Explanation of Symbols]

[0036] 1 Antenna 2 Main body 3-mode converter 4. Inverse Phase Transformation Section 40 Input section 41 T-shaped converter 42 Expansion section 43 Split part 431 First division output section 432 Second division output section 4311,4321 First direction moving part 4312,4322 Second direction moving part 44 In-phase distribution section 441 First in-phase section 442 Second in-phase part 45 180 degree phase shift section 48 First rectangular output section 49 Second rectangular output section 51 First semicircular output section 52 Second semicircular output section 6 TM01 Mode Generation Unit 7 Radiation section 8 Conical reflector 81 Sector-shaped rotating reflector

Claims

1. An inverse phase conversion unit having an input unit, a first rectangular output unit, and a second rectangular output unit, which converts the TE10 mode electromagnetic wave input to the input unit into two electromagnetic waves with a phase difference of 180° from each other, and outputs them to the first rectangular output unit and the second rectangular output unit, A first semicircular output unit connected to the first rectangular output unit and comprising a first semicircular output unit, A second semicircular output unit connected to the second rectangular output unit and comprising a second semicircular output unit, and A mode converter comprising a TM01 mode generation unit connected to the first semicircular output unit and the second semicircular output unit for generating the TM01 mode.

2. The aforementioned inverse phase conversion unit has a T-shaped conversion unit, The mode converter according to claim 1, wherein the T-shaped conversion unit converts from TE10 mode to TE20 mode.

3. A splitting unit that splits the TE20 mode electromagnetic wave generated in the T-shaped conversion unit into two electromagnetic waves with a phase difference of 180 degrees from each other. The mode converter according to claim 2, further comprising a first divided output unit that connects one of the two electromagnetic waves divided by the dividing unit to the first semicircular output unit, and a second divided output unit that connects the other of the two electromagnetic waves to the second semicircular output unit.

4. The mode converter according to claim 3, wherein the first divided output unit and the second divided output unit each include a first directional moving unit that moves parallel to either the long side or the short side of the input unit in a cross section perpendicular to the direction of propagation of electromagnetic waves, and a second directional moving unit that moves parallel to the other of the long side or the short side of the input unit.

5. The aforementioned inverse phase conversion unit is A phase distribution unit connected to the input unit distributes the data to a first phase unit and a second phase unit, which are in the same phase. It has a 180-degree phase shift section connected to the second in-phase section, The mode converter according to claim 1, wherein the first in-phase unit is connected to the first rectangular output unit, and the 180-degree phase shift unit is connected to the second rectangular output unit.

6. The mode converter according to any one of claims 1 to 5, wherein the inverse phase conversion unit does not have a resonant structure.

7. The mode converter according to any one of claims 1 to 5, wherein the inverse phase conversion unit has a symmetrical structure for converting into two electromagnetic waves.

8. A mode converter according to any one of claims 1 to 5, wherein the relative bandwidth is 13% or more.

9. A mode converter according to any one of claims 1 to 5, wherein the frequency of the electromagnetic wave is 110 GHz or higher.

10. An antenna having a mode converter according to any one of claims 1 to 5, Equipped with a conical reflector, The aforementioned conical reflector is positioned such that the axis of the cone is coaxial with the axis of the TM01 mode generation unit. An antenna that emits electromagnetic waves in a direction perpendicular to the axis of the aforementioned cone.

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