Dielectric waveguide converter

Abstract

To allow a dielectric waveguide to be connected to a waveguide with low loss.SOLUTION: A dielectric waveguide converter 1 includes: a dielectric waveguide 10 having a first tapered part 114 at or near an end part of a dielectric portion 13 composed 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 through which at least a part of the dielectric portion 13 can be inserted or penetrated. The first tapered part 114 of the dielectric waveguide 10 inserted into the first circular through-hole 210 and the second tapered part 211 of the first circular through-hole 210 of the first circular waveguide 21 face and contact each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A dielectric waveguide is a wired transmission medium in which a cylindrical dielectric with a different dielectric constant is disposed around a cylindrical dielectric. A coaxial cable is a wired transmission medium in which a cylindrical inner conductor is surrounded by a cylindrical insulator, which is further surrounded by a cylindrical outer conductor. Both dielectric waveguides and coaxial cables confine radio waves inside for transmission, but the higher the frequency, the greater the loss. However, because the increase in loss is smaller in dielectric waveguides than in coaxial cables, dielectric waveguides are often used as wired transmission media in high-frequency bands, and related technologies exist (e.g., Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-102939 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when connecting a dielectric waveguide to a waveguide, loss can increase due to differences in propagation modes, etc., so there was a need to develop technology that would enable connecting a dielectric waveguide to a waveguide with low loss. 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 the above object in mind, is a dielectric waveguide converter comprising: a dielectric waveguide having, at or near an end of a dielectric section consisting of a cylindrical inner dielectric and a cylindrical outer dielectric having a different dielectric constant and arranged so as to cover the outer periphery of the inner dielectric, a first tapered section whose diameter gradually or stepwise decreases towards the tip; and a first circular through hole having a circular cross section that allows at least a part of the dielectric section to be inserted into or to pass through, a second tapered section whose diameter gradually or stepwise decreases from a first side in a direction in which the dielectric section is inserted towards a second side on the opposite side, wherein the first tapered section of the dielectric waveguide and the second tapered section of the first circular through hole face each other and are in contact with each other when inserted into the first circular through hole. Here, the magnitude of transmission loss may vary depending on the axial length of the portion of the first tapered portion of the dielectric portion that is inserted into the first circular through hole. The device may further include a second circular waveguide having a second circular through hole with a circular cross-sectional shape into which the dielectric portion that passes 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 transmission loss may vary 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 waveguide having an elliptical through hole with an elliptical cross-sectional shape, which is connectable to the second circular through hole with the elliptical through hole communicating with the second circular through hole, and an elliptical waveguide having a square through hole with a square cross-sectional shape, which is connectable to the 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. [Effects of the Invention]

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

[0007] [Figure 1]1 is a diagram illustrating an example of the configuration of a dielectric waveguide converter according to an embodiment of the present invention; [Figure 2] 2 is a diagram showing the order of first to third transformations realized by the dielectric waveguide converter of FIG. 1. FIG. [Figure 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. [Figure 5] (A) and (B) are schematic diagrams showing how radio waves are transmitted through a dielectric waveguide. [Figure 6] (A) is a diagram showing an example of a configuration in which a rectangular waveguide is directly connected to a dielectric waveguide, and (B) is the S-parameters of the configuration in (A). [Figure 7] 1. (A) is a diagram showing an example of the configuration of the part that performs the first conversion of Fig. 2 in the dielectric waveguide converter of Fig. 1. (B) is an S-parameter of the configuration of the part that performs the first conversion. [Figure 8] 1. (A) is a diagram showing an example of the configuration of the part that performs the second conversion of Fig. 2 in the dielectric waveguide converter of Fig. 1. (B) is an S-parameter of the configuration of the part that performs the second conversion. [Figure 9] 1A is a diagram showing an example of the configuration of the part that performs the third conversion of FIG. 2 in the dielectric waveguide converter of FIG. 1. FIG. 1B is an S-parameter of the configuration of the part that performs the third conversion. DETAILED DESCRIPTION OF THE INVENTION

[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 this 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 5(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 the 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 that order, a first conversion that converts the dielectric waveguide 10 into a first circular waveguide 21, a second conversion that converts the first circular waveguide 21 into a second circular waveguide 22, and a third conversion that converts 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 a second axial end, a first circular waveguide 21 indicated by a dashed-line area A1, a second circular waveguide 22 indicated by a dashed-line area A2, an elliptical waveguide 23 indicated by 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 shown in Fig. 2. The second circular waveguide 22 is a waveguide connected to the first circular waveguide 21 to perform the second transformation shown 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 shown 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 portion 13 consisting of a cylindrical inner dielectric 12 and an outer dielectric 11 arranged to cover the outer periphery of the inner dielectric 12. The inner dielectric 12 and the outer dielectric 11 are made of dielectrics with different dielectric constants. Of these, the inner dielectric 12 is made of a dielectric such as PTFE (polytetrafluoroethylene). The outer dielectric 11 is made of a dielectric such as ePTFE (expanded polytetrafluoroethylene). The dielectric waveguide 10 mainly confines and transmits high-frequency band radio waves in the inner dielectric 12 of the dielectric portion 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 tapered region, and specifically, is a portion that is designed to have a diameter that gradually or stepwise decreases toward the tip on the second side at or near the end on the second side in the axial direction of the dielectric portion 13. 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 portion where 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 are continuous, and has a generally tapered shape as a whole.

[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. Furthermore, 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, the rectangular waveguide 30 is, for example, a 28 GHz EIA (Electronic Industries Alliance) standard WR-34.

[0016] When the dielectric waveguide converter 1 in Fig. 1 performs the first to third transformations 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] Figure 4(A) shows an example of the configuration of a dielectric waveguide without a tapered portion. The dielectric waveguide shown in Figure 4(A) is a wired transmission medium that has a cylindrical inner dielectric and a cylindrical outer dielectric with a different dielectric constant that is arranged around the inner dielectric and confines and transmits radio waves inside. The outer dielectric and inner dielectric form a dielectric portion. The dielectric portion is covered with a jacket made of a cylindrical insulator, except for the 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] Figure 4(B) shows a coaxial cable for comparison. The coaxial cable shown in Figure 4(B) is a wired transmission medium that has a cylindrical inner conductor, a cylindrical insulator disposed around the inner conductor, and a cylindrical outer conductor disposed around the cylindrical insulator, and transmits radio waves by confining them inside. The outer conductor, except for its second axial end or a portion in its vicinity, is covered by a jacket made of a cylindrical insulator, and a portion of the outer conductor is exposed from the second axial end of the jacket, a portion of the insulator is exposed from the second axial end of the outer conductor, and a portion of the inner conductor is exposed from the second axial end of the insulator.

[0019] The dielectric waveguide shown in Figure 4(A) and the coaxial cable shown in Figure 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 smaller 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 than the outer dielectric. r ) is larger for the outer dielectric than for the inner dielectric. In Figures 5(A) and (B), the thickness of the arrow indicates the magnitude of the radio wave, and the direction of the arrow indicates the direction of the radio wave.

[0021] In the example of Figure 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 increases. For this reason, as mentioned above, dielectric waveguides are often used as wired transmission media in the high-frequency band.

[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 radially outward from the dielectric waveguide, and the radio waves are not transmitted efficiently. Furthermore, 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, and the propagation mode of the rectangular waveguide is assumed to be the TEmn mode, with an impedance of 50Ω.

[0024] In the S-parameters of 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. Furthermore, line L11 indicates S11 of the configuration of 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 of Fig. 6(A).

[0025] For example, as shown by lines L11 and L12 in FIG. 6(B), in the configuration of FIG. 6(A), S11 is less than -30 dB and S21 is approximately -3 dB. In other words, the configuration of FIG. 6(A) has a radiation loss of about 3 dB, which is undesirable for a typical cable connection. Thus, in the configuration shown in FIG. 6(A), loss increases due to differences in the propagation mode, which is the path of the radio waves. In contrast, the dielectric waveguide converter 1 of FIG. 1 described above can achieve low-loss connection of a dielectric waveguide to a rectangular waveguide by using the three-stage conversion technique 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 pass through 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 whose diameter gradually or stepwise decreases from the first side, into which the dielectric portion 13 of the dielectric waveguide 10 is inserted, toward the second side in the axial direction.

[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 transmission of radio waves. In the example of Fig. 1, a cylindrical protective member 41 is arranged 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 second circular waveguide 22 to first circular waveguide 21 is not particularly limited, and they may be permanently connected by joining using techniques such as welding or adhesive, or may be temporarily connected using other detachable techniques. In the example of Fig. 1, a cylindrical protective member 42 is arranged on the outer periphery of 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 with the rectangular through hole 300 of the rectangular waveguide 30 when the second circular waveguide 22 and the elliptical waveguide 23 are connected and further when the elliptical waveguide 23 and the rectangular waveguide 30 are connected.

[0031] The method for connecting the elliptical waveguide 23 to the second circular waveguide 22 and the method for 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 adhesive, or they may be temporarily connected using another detachable method. In the example of Fig. 1, a cylindrical protective member 43 is arranged 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 with a rectangular cross-sectional shape. The rectangular waveguide 30 is made of a metal such as brass, bronze, copper, silver, or aluminum. The square 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 shown in FIG. 2 performed in the dielectric waveguide converter 1 shown 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 conversion converts the dielectric waveguide 10, which has the first tapered portion 114 in the dielectric portion 13, into the first circular waveguide 21, which has the second tapered portion 211 in the first circular through hole 210. The first conversion occurs because the propagation mode of the dielectric waveguide 10 is the HE11 mode, while 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, converting the HE11 mode to the TE11 mode can suppress loss during transmission.

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

[0035] FIG. 7B shows the S parameters of the configuration of the part that performs the first conversion. In the first transformation, the magnitude of 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 loss during transmission is selected as the value of the length D1 in FIG. 7(A).

[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), when the value of length D1 in Fig. 7(A) is 20 mm (millimeters), the loss is -0.05 dB or less. 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. 8A 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 the 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 in 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), when the value of length D2 in Fig. 8(A) is 20 mm (millimeters), the loss is less than -0.01 dB. 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. 9A is a diagram showing an example of the configuration of a portion that performs the third conversion 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 the elliptical waveguide 23, whose axial length D3 shown in Fig. 9(A) is approximately ¼ wavelength (λ), between the second circular waveguide 22 and the rectangular waveguide 30.

[0043] FIG. 9B shows the S parameters of the configuration of the part that performs the third conversion. The magnitude of transmission loss in the elliptical waveguide 23 disposed 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 easily suppresses transmission loss is selected as the value of the length D3 in Fig. 9(A). Note that, with regard to the diameters 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], which indicates 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) (¼λ), 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 on a variety of different embodiments. That is, the dielectric waveguide converter 1 is a dielectric waveguide converter comprising: a dielectric waveguide 10 having, at or near the end of a dielectric portion 13 composed 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, a first tapered portion 114 whose diameter gradually or stepwise decreases towards the tip; and a first circular through hole 210 having a circular cross section that allows at least a part of the dielectric portion 13 to be inserted into or pass through, a second tapered portion 211 whose diameter gradually or stepwise decreases from a first side in the insertion direction of the dielectric portion 13 towards a second side on the opposite side, wherein the tapered region 111 of the first tapered portion 114 of the dielectric waveguide 10 when 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.

[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 the loss during transmission 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, 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 can be designed to a length that further suppresses transmission loss.

[0048] The first circular waveguide 21 may further include a second circular through hole 220 having a circular cross-sectional shape that allows insertion of the dielectric portion 13 that has passed through the first circular through hole 210 of the first circular waveguide 21, and that can be connected to the first circular waveguide 21 with the dielectric portion 13 inserted in 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 where the dielectric portion 13 that passes through 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 vary 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, the magnitude of transmission loss varies depending on the axial length D2 of the portion of first tapered section 114 of dielectric section 13 that is inserted into second circular through hole 220. As a result, the axial length D2 of the portion of first tapered section 114 of dielectric section 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 section, which can be connected to the second circular through hole 220 with the elliptical through hole 230 communicating with the second circular through hole 220, and which can be connected to a rectangular waveguide 30 having a square through hole 300 with a square cross section 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 connects 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 vary depending on the axial length D3 of the elliptical waveguide 23. As a result, the magnitude of transmission loss changes 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-described embodiments. Furthermore, the effects of the present invention are not limited to those described in the above-described 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 a single 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 comprising 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 section, through which at least a part of the dielectric portion can be inserted or passed, 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 come into contact with each other.

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

3. the dielectric portion is inserted into the second circular through hole, and the second circular waveguide has a circular cross-sectional shape and can be connected to the first circular waveguide.

2. The dielectric waveguide transition according to claim 1.

4. the magnitude of transmission loss varies 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; 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 where the elliptical through hole is in communication with the second circular through hole; The elliptical through-hole can be connected to a rectangular waveguide having a rectangular through-hole with a rectangular cross section 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. The dielectric waveguide converter according to claim 5 .

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