Dielectric Waveguide Transition

Abstract

To enable a dielectric waveguide to be connected to a waveguide with low loss. [Solution] A dielectric waveguide converter (1) comprises a dielectric waveguide (10) having a first tapered portion (114) at or near the end of a dielectric portion (13) consisting of an inner dielectric (12) and an outer dielectric (11) having a different dielectric constant, and a first circular waveguide (21) having a second tapered portion (211) in a first circular through hole (210) into which at least a part of the dielectric portion (13) can be inserted or passed, and the first tapered portion (114) of the dielectric waveguide (10) inserted into the first circular through hole (210) and the second tapered portion (211) of the first circular through hole (210) of the first circular waveguide (21) face each other and are in contact with each other.

Description

[Technical field]

[0001] The present invention relates to a dielectric waveguide converter. [Background technology]

[0002] A dielectric waveguide is a wired transmission medium in which a cylindrical dielectric with a different dielectric constant is arranged around a cylindrical dielectric. A coaxial cable is a wired transmission medium in which a cylindrical insulator is arranged around a cylindrical inner conductor, and a cylindrical outer conductor is further arranged around that. Both the dielectric waveguide and the coaxial cable are capable of transmitting radio waves by confining them inside, and the higher the frequency, the greater the loss. However, since the increase in loss is smaller in a dielectric waveguide than in a coaxial cable, a dielectric waveguide is often used as a wired transmission medium in the high frequency band, and related technologies also exist (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-102939 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when connecting a dielectric waveguide to a waveguide, losses can increase due to differences in propagation modes, etc., so there has been a demand for the development of technology that enables connecting a dielectric waveguide to a waveguide with low losses. An object of the present invention is to enable a dielectric waveguide to be connected to a waveguide with low loss. [Means for solving the problem]

[0005] The present invention, which was completed with respect to this object, is a dielectric waveguide converter comprising: a dielectric waveguide having a first tapered portion at or near an end of a dielectric portion consisting of a cylindrical inner dielectric and a cylindrical outer dielectric having a different dielectric constant and arranged to cover the outer periphery of the inner dielectric, the first tapered portion gradually or stepwise decreasing in diameter toward the tip; and a first circular through hole having a circular cross-sectional shape through which at least a part of the dielectric portion can be inserted or passed through, the first tapered portion of the dielectric waveguide having a second tapered portion gradually or stepwise decreasing in diameter from a first side in a direction in which the dielectric portion is inserted toward a second side on the opposite side, the first tapered portion of the dielectric waveguide when inserted into the first circular through hole faces and contacts the second tapered portion of the first circular through hole. Here, a magnitude of loss during transmission may vary depending on an axial length of a portion of the first tapered portion of the dielectric portion that is inserted into the first circular through hole. The waveguide may further include a second circular waveguide having a second circular through hole with a circular cross-sectional shape into which the dielectric portion passing through the first circular through hole can be inserted, and which can be connected to the first circular waveguide with the dielectric portion inserted into the second circular through hole. Furthermore, the magnitude of loss during transmission may change depending on the axial length of the portion of the first tapered portion of the dielectric portion that is inserted into the second circular through hole. The waveguide may further include an elliptical through hole having an elliptical cross-sectional shape and capable of being connected to the second circular through hole with the elliptical through hole communicating with the second circular through hole, and an elliptical waveguide having a rectangular through hole having a square cross-sectional shape and capable of being connected to a rectangular waveguide with the elliptical through hole communicating with the rectangular waveguide. Furthermore, the magnitude of transmission loss may vary depending on the axial length of the elliptical waveguide. Effect of the Invention

[0006] According to the present invention, a dielectric waveguide can be connected to a waveguide with low loss. [Brief description of the drawings]

[0007] [Figure 1]1 is a diagram showing an example of a configuration of a dielectric waveguide converter according to an embodiment of the present invention; [Diagram 2] 2 is a diagram showing a sequence of first to third transformations realized by the dielectric waveguide converter of FIG. 1. [Diagram 3] 2 shows the S-parameters of the dielectric waveguide converter in FIG. 1. [Figure 4] 1A is a diagram showing an example of the configuration of an end portion of a dielectric waveguide, and FIG. 1B is a diagram showing an example of the configuration of an end portion of a coaxial cable. [Diagram 5] 1A and 1B are schematic diagrams showing how radio waves are transmitted through a dielectric waveguide. [Figure 6] 1A is a diagram showing an example of a configuration in which a rectangular waveguide is directly connected to a dielectric waveguide, and FIG. 1B is a diagram showing the S-parameters of the configuration in FIG. [Figure 7] Fig. 3A is a diagram showing an example of the configuration of a portion that performs the first conversion in Fig. 2 in the dielectric waveguide converter in Fig. 1. Fig. 3B is an S-parameter of the configuration of the portion that performs the first conversion. [Figure 8] Fig. 3A is a diagram showing an example of the configuration of a portion that performs the second conversion of Fig. 2 in the dielectric waveguide converter of Fig. 1. Fig. 3B is an S-parameter of the configuration of the portion that performs the second conversion. [Figure 9] Fig. 3A is a diagram showing an example of the configuration of a portion that performs the third transformation in Fig. 2 in the dielectric waveguide converter in Fig. 1. Fig. 3B is an S-parameter of the configuration of the portion that performs the third transformation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Configuration of Dielectric Waveguide Converter 1> FIG. 1 is a diagram showing an example of the configuration of a dielectric waveguide converter 1 according to the present embodiment. FIG. 2 is a diagram showing the sequence of the first to third transformations realized by the dielectric waveguide converter 1 of FIG. FIG. 3 shows S parameters (Scattering parameters) of the dielectric waveguide converter 1 of FIG. Fig. 4(A) is a diagram showing an example of the configuration of an end portion of a dielectric waveguide, and Fig. 4(B) is a diagram showing an example of the configuration of an end portion of a coaxial cable. 5(A) and (B) are schematic diagrams showing how radio waves are transmitted through a dielectric waveguide. Fig. 6(A) is a diagram showing an example of a configuration in which a rectangular waveguide is directly connected to a dielectric waveguide, and Fig. 6(B) shows S parameters of the configuration in Fig. 6(A).

[0009] The dielectric waveguide converter 1 shown in Fig. 1 is a connector for converting a dielectric waveguide 10 into a rectangular waveguide 30 through three-stage conversion. The three-stage conversion refers to performing, in the order of, a first conversion for converting the dielectric waveguide 10 into a first circular waveguide 21, a second conversion for converting the first circular waveguide 21 into a second circular waveguide 22, and a third conversion for converting the second circular waveguide 22 into a rectangular waveguide 30, as shown in Fig. 2.

[0010] As shown in Fig. 1, the dielectric waveguide converter 1 includes a dielectric waveguide 10 having a first tapered portion 114 at or near an end portion on the second axial side, a first circular waveguide 21 shown in a dashed line area A1, a second circular waveguide 22 shown in a dashed line area A2, an elliptical waveguide 23 shown in a dashed line area A3, and a rectangular waveguide 30. Of these, the first circular waveguide 21 is a waveguide connected to the dielectric waveguide 10 to perform the first transformation in Fig. 2. The second circular waveguide 22 is a waveguide connected to the first circular waveguide 21 to perform the second transformation in Fig. 2. The elliptical waveguide 23 is a waveguide connected to the second circular waveguide 22 and the rectangular waveguide 30 to perform the third transformation in Fig. 2.

[0011] (Dielectric Waveguide 10) The dielectric waveguide 10 constituting the dielectric waveguide converter 1 is a wired transmission medium having a dielectric part 13 consisting of a cylindrical inner dielectric 12 and an outer dielectric 11 arranged so as to cover the outer periphery of the inner dielectric 12. The inner dielectric 12 and the outer dielectric 11 are respectively composed of dielectrics having different dielectric constants. Of these, the inner dielectric 12 is composed of a dielectric such as PTFE (polytetrafluoroethylene). The outer dielectric 11 is composed of a dielectric such as ePTFE (expanded polytetrafluoroethylene). The dielectric waveguide 10 mainly confines and transmits radio waves in a high frequency band in the inner dielectric 12 of the dielectric part 13. The propagation mode of the dielectric waveguide 10 is assumed to be the HE11 mode.

[0012] The dielectric waveguide 10 has a first tapered portion 114 at or near the end of the dielectric portion 13. The first tapered portion 114 is a portion that includes at least a portion of a tapered region, and specifically, is a portion designed to have a gradually or stepwise smaller diameter at or near the end on the second side in the axial direction of the dielectric portion 13 toward the tip on the second side. This gives the first tapered portion 114 a tapered or approximately tapered shape as a whole.

[0013] In the example of Figure 1, the first tapered section 114 is a continuous section consisting of a tapered region 111 formed near the end of the outer dielectric 11, a non-tapered region 112 formed parallel to the axial direction of the dielectric waveguide 10, and a tapered region 113 formed at the tip portion of the inner dielectric 12, and has an approximately tapered shape overall.

[0014] 2, the dielectric waveguide converter 1 converts the HE11 mode of the dielectric waveguide 10 into the TE11 mode of the first circular waveguide 21. Moreover, the dielectric waveguide converter 1 converts the dielectric portion 13 of the dielectric waveguide 10 inserted into the first circular through hole 210 of the first circular waveguide 21 into the second circular through hole 220 of the second circular waveguide 22, as the second conversion in FIG.

[0015] 2, the dielectric waveguide converter 1 converts the second circular through hole 220 of the second circular waveguide 22 into an elliptical through hole 230 of the elliptical waveguide 23, and further converts it into a rectangular through hole 300 of the rectangular waveguide 30. In this embodiment, a 28 GHz EIA (Electronic Industries Alliance) standard WR-34 is adopted as an example of the rectangular waveguide 30.

[0016] When the dielectric waveguide converter 1 in Fig. 1 performs the first to third conversions in Fig. 2, the S parameters shown in Fig. 3 are obtained as analysis results. In the S parameters in Fig. 3, the horizontal axis is frequency (Frequency [GHz]), the vertical axis (left side) is S11 [dB] indicating the reflection characteristic, and the vertical axis (right side) is S21 [dB] indicating the transmission characteristic. In the S parameters in Fig. 3, line L1 indicates S21, and line L2 indicates S11. As shown in Fig. 3, the dielectric waveguide converter 1 enables radio waves to be transmitted from the dielectric waveguide 10 to the rectangular waveguide 30 with only a loss of about 0.1 dB.

[0017] FIG. 4(A) shows an example of the configuration of a dielectric waveguide that does not have a tapered portion. The dielectric waveguide shown in FIG. 4(A) is a wired transmission medium that has a cylindrical inner dielectric and a cylindrical outer dielectric with a different dielectric constant arranged around the inner dielectric, and transmits radio waves by confining them inside. The outer dielectric and the inner dielectric form a dielectric portion. The dielectric portion is covered with a jacket made of a cylindrical insulator except for an end portion on the second axial side or a portion in the vicinity thereof, and a part of the outer dielectric is exposed from the end portion on the second axial side of the jacket, and a part of the inner dielectric is exposed from the end portion on the second axial side of the outer dielectric.

[0018] A coaxial cable for comparison is shown in Fig. 4(B). The coaxial cable shown in Fig. 4(B) is a wired transmission medium that has a cylindrical inner conductor, a cylindrical insulator arranged around the inner conductor, and a cylindrical outer conductor arranged around the cylindrical inner conductor, and transmits radio waves by confining them inside. The outer conductor is covered with a jacket made of a cylindrical insulator except for its second axial end or a portion in its vicinity, and a part of the outer conductor is exposed from the second axial end of the jacket, a part of the insulator is exposed from the second axial end of the outer conductor, and a part of the inner conductor is exposed from the second axial end of the insulator.

[0019] The dielectric waveguide shown in Fig. 4(A) and the coaxial cable shown in Fig. 4(B) are wired transmission media that confine radio waves inside and transmit them, and in both cases the loss increases as the frequency increases. However, the increase in loss as the frequency increases is less in the dielectric waveguide than in the coaxial cable. For this reason, the dielectric waveguide is often used as a wired transmission medium in the high-frequency band.

[0020] In Fig. 5(A), the dielectric constant (ε r ) is larger for the inner dielectric than for the outer dielectric. Also, Fig. 5(B) shows the state of radio wave transmission when the dielectric constant (ε r 5(A) and (B), the thickness of the arrow indicates the strength of the radio wave, and the direction of the arrow indicates the direction of the radio wave.

[0021] In the example of FIG. 5(A), the dielectric constant of the inner dielectric (ε r ) is "2.2", and the dielectric constant of the outer dielectric (ε r ) is "1.3", so the dielectric constant (ε r) is larger for the inner dielectric than for the outer dielectric. In this case, radio waves are transmitted so as to be focused toward the radially inner axis of the dielectric waveguide, so that an increase in loss is suppressed even when the frequency becomes high. For this reason, dielectric waveguides are often used as wired transmission media in the high frequency band, as mentioned above.

[0022] In contrast, in the example of FIG. 5(B), the dielectric constant of the inner dielectric (ε r ) is "1.3", and the dielectric constant of the outer dielectric (ε r ) is "2.2", so the dielectric constant (ε r ) is larger for the outer dielectric than for the inner dielectric. In this case, the radio waves are diffused toward the outside in the radial direction of the dielectric waveguide, and the radio waves are not transmitted efficiently. In addition, dielectric waveguides are not only used independently, but are also sometimes connected to waveguides or coaxial cables depending on the application.

[0023] In the example of Fig. 6(A), the rectangular waveguide is assumed to be WR-34 of the EIA standard at 28 GHz. Also, the propagation mode of the rectangular waveguide is assumed to be the TEmn mode, and the impedance is assumed to be 50Ω.

[0024] In the S-parameters in Fig. 6(B), the horizontal axis is frequency (Frequency [GHz]), the vertical axis (left side) is S11 [dB] indicating the reflection characteristic, and the vertical axis (right side) is S21 [dB] indicating the transmission characteristic. Line L11 indicates S11 of the configuration in Fig. 6(A) (the configuration in which the dielectric waveguide and the rectangular waveguide are directly connected), and line L12 indicates S21 of the configuration in Fig. 6(A).

[0025] For example, as shown by lines L11 and L12 in FIG. 6B, in the configuration of FIG. 6A, S11 is less than -30 dB, and S21 is about -3 dB. That is, in the configuration of FIG. 6A, the loss due to radiation is about 3 dB, which is an undesirable characteristic for a general cable connection. Thus, in the configuration shown in FIG. 6A, the loss increases due to the difference in the propagation mode, which is the path of the radio waves. In contrast, according to the dielectric waveguide converter 1 of FIG. 1 described above, the connection of the dielectric waveguide to the rectangular waveguide can be realized with low loss by the three-stage conversion method of FIG. 2 described above.

[0026] (First circular waveguide 21) Returning to FIG. 1, the first circular waveguide 21 is a waveguide having a first circular through hole 210 with a circular cross section. The first circular waveguide 21 is made of a metal such as brass, bronze, copper, silver, or aluminum. The first circular through hole 210 is a through hole that allows at least a part of the dielectric portion 13 of the dielectric waveguide 10 to be inserted or penetrated from a first side to a second side in the axial direction. The first circular through hole 210 is formed with a second tapered portion 211 that gradually or stepwise decreases in diameter from the first side to the second side in the axial direction where the dielectric portion 13 of the dielectric waveguide 10 is inserted.

[0027] When the dielectric waveguide 10 is inserted into the first circular through hole 210, the tapered region 111 of the first tapered portion 114 of the dielectric portion 13 of the dielectric waveguide 10 and the second tapered portion 211 of the first circular through hole 210 face each other and come into contact with each other, enabling the transmission of radio waves. In the example of Fig. 1, a cylindrical protective member 41 is disposed on the outer periphery of the first circular waveguide 21.

[0028] (Second circular waveguide 22) The second circular waveguide 22 is a waveguide having a second circular through hole 220 with a circular cross section. The second circular waveguide 22 is made of a metal such as brass, bronze, copper, silver, or aluminum. The second circular through hole 220 is a through hole into which the tip portion of the dielectric portion 13 of the dielectric waveguide 10 that has passed through the first circular through hole 210 of the first circular waveguide 21 can be inserted. The second circular waveguide 22 is connected to the first circular waveguide 21 with the tip portion of the dielectric portion 13 of the dielectric waveguide 10 inserted into the second circular through hole 220.

[0029] The method for connecting the second circular waveguide 22 to the first circular waveguide 21 is not particularly limited, and they may be permanently connected by joining using a method such as welding or adhesive, or may be temporarily connected using another detachable method. In the example of Fig. 1, a cylindrical protective member 42 is disposed on the outer periphery of the second circular waveguide 22.

[0030] (Elliptical Waveguide 23) The elliptical waveguide 23 is a waveguide having an elliptical through hole 230 whose cross section is elliptical. The elliptical waveguide 23 is made of a metal such as brass, bronze, copper, silver, or aluminum. The elliptical through hole 230 is a through hole that communicates with the second circular through hole 220 of the second circular waveguide 22 and further communicates with the rectangular through hole 300 of the rectangular waveguide 30 in a state in which the second circular waveguide 22 and the elliptical waveguide 23 are connected and further the elliptical waveguide 23 and the rectangular waveguide 30 are connected.

[0031] The method of connecting the elliptical waveguide 23 to the second circular waveguide 22 and the method of connecting the elliptical waveguide 23 to the rectangular waveguide 30 are not particularly limited. For example, they may be permanently connected by joining using a method such as welding or bonding, or may be temporarily connected using another detachable method. In the example of Fig. 1, a cylindrical protective member 43 is disposed on the outer periphery of the elliptical waveguide 23.

[0032] (Square waveguide 30) The rectangular waveguide 30 is a waveguide having a rectangular through hole 300 whose cross section is rectangular. The rectangular waveguide 30 is made of a metal such as brass, bronze, copper, silver, or aluminum. The rectangular through hole 300 is a through hole that communicates with the second circular through hole 220 of the second circular waveguide 22 when the rectangular waveguide 30 is connected to the elliptical waveguide 23. In the example of FIG. 1, a cylindrical protective member 53 is disposed on the outer periphery of the rectangular waveguide 30.

[0033] Hereinafter, the first to third transformations in FIG. 2 performed in the dielectric waveguide converter 1 in FIG. 1 will be described in detail with reference to FIGS. <First conversion> FIG. 7A is a diagram showing an example of the configuration of a portion that performs the first conversion in FIG. 2 in the dielectric waveguide converter 1 in FIG. The first transformation transforms the dielectric waveguide 10 having the first tapered portion 114 in the dielectric portion 13 into the first circular waveguide 21 having the second tapered portion 211 in the first circular through hole 210. The first transformation is performed because the propagation mode of the dielectric waveguide 10 is the HE11 mode, whereas the propagation mode of the first circular waveguide 21 is the TE11 mode. Since the HE11 mode and the TE11 mode have the same circular electromagnetic field distribution, the loss during transmission can be suppressed by transforming the HE11 mode into the TE11 mode.

[0034] 7 to 9, the diameter r1 of the dielectric portion 13 (i.e., the diameter of the end portion on the first axial side of the first circular through hole 210) is 21.4 mm (millimeters). The diameter r2 of the inner dielectric 12 constituting the dielectric portion 13 is 6.4 mm (millimeters). The diameter r3 of the end portion on the second axial side of the tapered region 111 of the dielectric portion 13 (i.e., the diameter of the end portion on the second axial side of the first circular through hole 210 of the first circular waveguide 21) is 8 mm (millimeters), which is optimal when the frequency is 28 GHz.

[0035] FIG. 7B shows the S parameters of the configuration of the portion that performs the first conversion. In the first transformation, the magnitude of the loss during transmission changes depending on the value of the axial length D1 of the tapered region 111 of the dielectric portion 13. For this reason, in designing the tapered region 111, a value that easily suppresses the loss during transmission is selected as the value of the length D1 in FIG.

[0036] For example, in the S parameters of Fig. 7(B), the horizontal axis is frequency (Frequency [GHz]) and the vertical axis is S21 [dB] indicating the transmission characteristic. In the S parameters of Fig. 7(B), line L21 indicates that the value of length D1 in Fig. 7(A) is 5 mm (millimeters), line L22 indicates that the value of length D1 is 10 mm (millimeters), and line L23 indicates that the value of length D1 is 15 mm (millimeters). Furthermore, line L24 indicates that the value of length D1 is 20 mm (millimeters), and line L25 indicates that the value of length D1 is 25 mm (millimeters).

[0037] As shown in Fig. 7(B), the loss is -0.05 dB or less when the value of length D1 in Fig. 7(A) is 20 mm (millimeters). Therefore, by selecting 20 mm (millimeters) as the value of length D1 in the axial direction of tapered region 111 in Fig. 7(A), the loss during transmission can be minimized.

[0038] <Second conversion> FIG. 8(A) is a diagram showing an example of the configuration of a portion that performs the second conversion in FIG. 2 in the dielectric waveguide converter 1 in FIG. The second transformation is to transform the first circular waveguide 21 into the second circular waveguide 22. Specifically, the second transformation is to transform the tapered region 113 at the tip portion on the second axial side of the dielectric portion 13 inserted into the second circular waveguide 22 into a second circular through hole 220 of the second circular waveguide 22.

[0039] FIG. 8B shows the S parameters of the configuration of the part that performs the second conversion. The magnitude of transmission loss of tapered region 113 inserted into second circular through hole 220 of second circular waveguide 22 changes depending on the value of axial length D2. For this reason, in designing tapered region 113, a value that easily suppresses transmission loss is selected as the value of length D2 in FIG. 8(A).

[0040] For example, in the S parameters of Fig. 8(B), the horizontal axis is frequency (Frequency [GHz]) and the vertical axis is S21 [dB] indicating the transmission characteristic. In the S parameters of Fig. 8(B), line L31 indicates that the value of length D2 in Fig. 8(A) is 5 mm (millimeters), line L32 indicates that the value of length D2 is 10 mm (millimeters), and line L33 indicates that the value of length D2 is 15 mm (millimeters). Furthermore, line L34 indicates that the value of length D2 is 20 mm (millimeters), and line L35 indicates that the value of length D2 is 25 mm (millimeters).

[0041] As shown in Fig. 8(B), the loss is less than -0.01 dB when the value of length D2 in Fig. 8(A) is 20 mm (millimeters). Therefore, by selecting 20 mm (millimeters) as the value of length D2 in the axial direction of tapered region 113, the loss during transmission can be minimized.

[0042] <Third conversion> FIG. 9(A) is a diagram showing an example of the configuration of a portion that performs the third transformation in FIG. 2 in the dielectric waveguide converter 1 in FIG. 1 into a rectangular waveguide 30 via an elliptical waveguide 23 shown in Fig. 9(A). Specifically, the third transformation transforms the second circular through hole 220 of the second circular waveguide 22 into an elliptical through hole 230 of the elliptical waveguide 23, and further into a rectangular through hole 300 of the rectangular waveguide 30, by disposing an elliptical waveguide 23 having an axial length D3 of about ¼ wavelength (λ) shown in Fig. 9(A) between the second circular waveguide 22 and the rectangular waveguide 30.

[0043] FIG. 9B shows the S parameters of the configuration of the portion that performs the third conversion. The magnitude of transmission loss of the elliptical waveguide 23 arranged between the second circular waveguide 22 and the rectangular waveguide 30 varies depending on the value of the axial length D3 shown in Fig. 9(A) described above. For this reason, in designing the elliptical waveguide 23, a value that is likely to suppress transmission loss is selected as the value of the length D3 in Fig. 9(A). Note that, with regard to the diameter of the elliptical through hole 230 of the elliptical waveguide 23 according to this embodiment, the diameter r4 shown in Fig. 9(A) is 2.7 mm (millimeters) and the diameter r5 is 5.6 mm (millimeters).

[0044] For example, in the S-parameters of Fig. 9(B), the horizontal axis is frequency (Frequency [GHz]) and the vertical axis is S21 [dB] indicating the transmission characteristic. In the S-parameters of Fig. 9(B), line L41 indicates that when the value of length D3 in Fig. 9(A) is 3.7 mm (millimeters) (1 / 4λ), the loss is less than -0.01 dB. Therefore, by selecting 3.7 mm (millimeters) as the value of length D3 in the axial direction of elliptical waveguide 23, the loss during transmission can be suppressed.

[0045] In summary, the dielectric waveguide converter 1 according to the first embodiment of the present invention only needs to have the following configuration, and can take a variety of different embodiments. That is, the dielectric waveguide converter 1 is a dielectric waveguide converter comprising: a dielectric waveguide 10 having a first tapered portion 114 at or near an end of a dielectric portion 13 consisting of a cylindrical inner dielectric 12 and a cylindrical outer dielectric 11 having a different dielectric constant and arranged to cover the outer periphery of the inner dielectric 12, the first tapered portion 114 gradually or stepwise decreasing in diameter towards the tip; and a first circular through hole 210 having a circular cross-sectional shape through which at least a part of the dielectric portion 13 can be inserted or passed through, the first circular waveguide 21 having a second tapered portion 211 gradually or stepwise decreasing in diameter from a first side in a direction in which the dielectric portion 13 is inserted towards a second side on the opposite side, the first circular through hole 210 being inserted into the first circular through hole 210, in which the tapered region 111 of the first tapered portion 114 of the dielectric waveguide 10 and the second tapered portion 211 of the first circular through hole 210 of the first circular waveguide 21 face each other and are in contact with each other.

[0046] As a result, the tapered region 111 of the first tapered portion 114 of the dielectric waveguide 10 inserted into the first circular through hole 210 faces and contacts the second tapered portion 211 of the first circular through hole 210. As a result, a first conversion that converts the propagation mode becomes possible, and loss during transmission can be suppressed.

[0047] Here, the magnitude of transmission loss may vary depending on the axial length D1 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into first circular through hole 210 of first circular waveguide 21. As a result, the magnitude of transmission loss varies depending on the axial length D1 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into first circular through hole 210 of first circular waveguide 21. As a result, axial length D1 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into first circular through hole 210 can be designed to a length that further suppresses transmission loss.

[0048] The waveguide may further include a second circular through hole 220 having a circular cross-sectional shape into which the dielectric portion 13 passing through the first circular through hole 210 of the first circular waveguide 21 can be inserted, and which can be connected to the first circular waveguide 21 with the dielectric portion 13 inserted into the second circular through hole 220. This provides the second circular waveguide 22 that can be connected to the first circular waveguide 21 in a state in which the dielectric portion 13 that penetrates the first circular through hole 210 of the first circular waveguide 21 is inserted into the second circular through hole 220. As a result, a second transformation that transforms the first circular waveguide 21 into the second circular waveguide 22 becomes possible.

[0049] Furthermore, the magnitude of the loss during transmission may change depending on the axial length D2 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into second circular through hole 220. This causes the magnitude of transmission loss to change depending on the axial length D2 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into second circular through hole 220. As a result, axial length D2 of the portion of first tapered portion 114 of dielectric portion 13 that is inserted into second circular through hole 220 can be designed to a length that further suppresses transmission loss.

[0050] The waveguide may further include an elliptical waveguide 23 having an elliptical through hole 230 with an elliptical cross-sectional shape and connectable to the second circular through hole 220 with the elliptical through hole 230 communicating with the second circular through hole 220, and an elliptical waveguide 23 connectable to a rectangular waveguide 30 having a square through hole 300 with a square cross-sectional shape and with the elliptical through hole 230 communicating with the rectangular waveguide 30. This provides an elliptical waveguide 23 having an elliptical through hole 230 that communicates the second circular through hole 220 of the second circular waveguide 22 with the rectangular through hole 300 of the rectangular waveguide 30. As a result, a third conversion is possible in which the second circular waveguide 22 is converted into the rectangular waveguide 30 via the elliptical waveguide 23.

[0051] Furthermore, the magnitude of the transmission loss may change according to the axial length D3 of the elliptical waveguide 23. This causes the magnitude of transmission loss to change depending on the axial length D3 of the elliptical waveguide 23. As a result, the axial length D3 of the elliptical waveguide 23 can be designed to a length that further suppresses transmission loss.

[0052] <Other embodiments> Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments. Furthermore, the effects of the present invention are not limited to those described in the above-mentioned embodiments. For example, the configuration of the dielectric waveguide converter 1 shown in FIG. 1 is merely an example for achieving the object of the present invention, and is not particularly limited.

[0053] For example, the first tapered section 114 formed in the dielectric section 13 of the dielectric waveguide 10 of the dielectric waveguide converter 1 in Fig. 1 is composed of a tapered region 111, a non-tapered region 112, and a tapered region 113. Therefore, the dielectric section 13 has two tapered regions (tapered regions 111 and 113) toward the tip, but is not limited to this. For example, although not shown, the dielectric section 13 may have one tapered region with no steps toward the tip. [Explanation of symbols]

[0054] 1...dielectric waveguide converter, 10...dielectric waveguide, 11...outer dielectric, 12...inner dielectric, 13...dielectric portion, 21...first circular waveguide, 22...second circular waveguide, 23...elliptical waveguide, 30...rectangular waveguide, 111, 113...tapered region, 112...non-tapered region, 114...first tapered portion, 210...first circular through hole, 211...second tapered portion, 220...second circular through hole, 230...elliptical through hole, 300...rectangular through hole

Claims

1. a dielectric waveguide having a first tapered portion at or near an end of a dielectric portion including a cylindrical inner dielectric and a cylindrical outer dielectric having a different dielectric constant and arranged so as to cover an outer periphery of the inner dielectric, the first tapered portion having a diameter gradually or stepwise decreasing toward a tip; a first circular through hole having a circular cross-sectional shape through which at least a part of the dielectric portion can be inserted or passed through, and a second tapered portion having a diameter that gradually or stepwise decreases from a first side in a direction in which the dielectric portion is inserted toward a second side on the opposite side; Equipped with a dielectric waveguide converter in which the first tapered portion of the dielectric waveguide inserted into the first circular through hole and the second tapered portion of the first circular through hole face each other and are in contact with each other.

2. a magnitude of loss during transmission varies depending on an axial length of a portion of the first tapered portion of the dielectric portion that is inserted into the first circular through hole; 2. The dielectric waveguide transition of claim 1.

3. a second circular through hole having a circular cross-sectional shape into which the dielectric portion passing through the first circular through hole can be inserted, and a second circular waveguide connectable to the first circular waveguide in a state in which the dielectric portion is inserted into the second circular through hole; 2. The dielectric waveguide transition of claim 1.

4. a magnitude of transmission loss varies depending on an axial length of a portion of the first tapered portion of the dielectric portion that is inserted into the second circular through hole; 4. The dielectric waveguide converter according to claim 3.

5. an elliptical through hole having an elliptical cross-sectional shape, the elliptical through hole being connected to the second circular through hole in a state in which the elliptical through hole is connected to the second circular through hole; The elliptical through hole can be connected to a rectangular waveguide having a rectangular through hole with a cross-sectional shape of a square in a state where the elliptical through hole is in communication with the rectangular waveguide. further comprising an elliptical waveguide; 4. The dielectric waveguide converter according to claim 3.

6. The magnitude of transmission loss varies depending on the axial length of the elliptical waveguide.

6. The dielectric waveguide converter according to claim 5.

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