Mode conversion structure

Abstract

A mode conversion device according to an embodiment of the present disclosure comprises: a first dielectric substrate that has a microstrip line that is constituted by a line conductor and a first ground conductor that faces the line conductor, said first dielectric substrate having a first thickness; a second dielectric substrate that has a post wall waveguide that includes a first conductor layer that is connected to the line conductor in the same plane and a second conductor layer that faces the first conductor layer, said second dielectric substrate having a second thickness that is thicker than the first thickness; and a first via that electrically connects the first ground conductor and the second conductor layer.

Description

Technical Field

[0001] The present disclosure relates to a mode conversion structure.

Background Art

[0002] As a means for transmitting a high-frequency signal on a dielectric substrate, a microstrip line is often used. However, in frequency bands such as millimeter waves and terahertz waves, due to the skin effect, which is a high-frequency specific phenomenon, and the influence of surface irregularities, the transmission loss due to conductor loss increases.

[0003] By increasing the thickness of the dielectric (substrate) constituting the microstrip line, the conductor loss can be reduced. However, in this case, the radiation loss, which radiates energy as an electromagnetic wave, increases, making it difficult to reduce the transmission loss.

[0004] On the other hand, as one means of reducing transmission loss, a dielectric is sandwiched between a pair of conductor layers, and the conductor layers are electrically connected by a via hole group arranged at intervals of λ / 2 (λ: wavelength of electromagnetic wave) in the signal transmission direction (propagation direction of electromagnetic wave). There is a post-wall waveguide structure that uses the main conductor layer as the broad wall of the waveguide and the via hole group as the narrow wall of the waveguide. Since the post-wall waveguide is surrounded by conductors on all four sides, even if the substrate thickness is increased, the radiation loss does not increase. Therefore, the dielectric can be thickened, and it is possible to simultaneously reduce the conductor loss and the radiation loss.

[0005] Considering the mounting of an integrated circuit (IC: Integrated Circuit) that generates a high-frequency signal, the IC is often mounted on a microstrip line via solder balls, and it is difficult to directly supply power to the post-wall waveguide. Therefore, when using the post-wall waveguide as a transmission line, a propagation (transmission) mode conversion structure (hereinafter simply referred to as a mode conversion structure) that connects the microstrip line and the post-wall waveguide is configured. Note that the mode conversion structure may be read as a mode conversion device or the like.

[0006] As an existing technology for mode conversion structures, for example, Patent Document 1 discloses a mode conversion structure in which the line conductor of a microstrip line and one broad wall of a post-wall waveguide are in the same plane, and the ground conductor (hereinafter referred to as GND) of the microstrip line and the other broad wall of the post-wall waveguide are in the same plane (connecting a microstrip line and a post-wall waveguide of the same thickness). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2004-153368 [Overview of the Initiative]

[0008] However, in the existing technology described in Patent Document 1, the thickness of the microstrip line and the thickness of the post-wall waveguide are the same, making it difficult to connect a microstrip line and a post-wall waveguide with different thicknesses.

[0009] In the existing technology described in Patent Document 1, when connecting a thin microstrip line and a thin post-wall waveguide, the radiation loss is small and the conductor loss is large, and when connecting a thick microstrip line and a thick post-wall waveguide, the conductor loss is small and the radiation loss is large, making it difficult to reduce the radiation loss of the microstrip line or the conductor loss of the post-wall waveguide.

[0010] Non-limiting embodiments of this disclosure contribute to providing a mode conversion structure that can connect microstrip lines and post-wall waveguides of different thicknesses while suppressing transmission loss.

[0011] A mode conversion structure according to one embodiment of the present disclosure comprises a first dielectric substrate having a first thickness and having a microstrip line composed of a line conductor and a first ground conductor facing the line conductor; a second dielectric substrate having a second thickness greater than the first thickness and having a post-wall waveguide including a first conductor layer connected on the same plane as the line conductor and a second conductor layer facing the first conductor layer; and a first via electrically connecting the first ground conductor and the second conductor layer.

[0012] According to one embodiment of the present disclosure, it is possible to connect microstrip lines and post-wall waveguides of different thicknesses while suppressing transmission loss.

[0013] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features. [Brief explanation of the drawing]

[0014] [Figure 1] A perspective view showing a mode conversion structure according to Embodiment 1 of this disclosure. [Figure 2] Side cross-sectional view showing a mode conversion structure according to Embodiment 1 of this disclosure [Figure 3] Perspective view showing a mode conversion structure related to a comparative example (an example using existing technology) [Figure 4] Side cross-sectional view showing the mode conversion structure related to the comparative example. [Figure 5] This figure shows the simulation results of the radiated power of the mode conversion structure according to Embodiment 1 of this disclosure and the mode conversion structure according to the comparative example. [Figure 6] A perspective view showing a mode conversion structure according to Embodiment 2 of this disclosure. [Figure 7] Side cross-sectional view showing a mode conversion structure according to Embodiment 2 of this disclosure [Figure 8]Figure showing the simulation results of the passing characteristics of the mode conversion structure according to Embodiment 2 of the present disclosure and the mode conversion structure according to the comparative example [Figure 9] Perspective view showing the mode conversion structure according to a modification of Embodiment 2 of the present disclosure [Figure 10] Side cross-sectional view showing the mode conversion structure according to a modification of Embodiment 2 of the present disclosure [Figure 11] Perspective view showing the mode conversion structure according to Embodiment 3 of the present disclosure [Figure 12] Side cross-sectional view showing the mode conversion structure according to Embodiment 3 of the present disclosure [Figure 13] Figure showing the simulation results of the passing characteristics of the mode conversion structure according to Embodiment 3 of the present disclosure and the mode conversion structure according to the comparative example [Figure 14] Side cross-sectional view showing the mode conversion structure according to a modification of Embodiment 3 of the present disclosure

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with appropriate reference to the drawings. However, a more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of substantially the same configurations may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art.

[0016] Note that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0017] In this specification, the positive Z-axis direction shown in the drawings is referred to as up (direction), and the negative Z-axis direction is referred to as down (direction). Also, in various drawings, for ease of viewing, some elements such as the side surface of the mode conversion structure (a plane parallel to the YZ plane shown in the drawings) are omitted, and some elements may not be drawn to scale.

[0018] (Embodiment 1) <Configuration of the mode conversion structure> Figure 1 is a perspective view showing a mode conversion structure 10 according to Embodiment 1 of the present disclosure, and Figure 2 is a side cross-sectional view (A-A' cross-sectional view) showing the mode conversion structure 10.

[0019] As shown in Figures 1 and 2, the mode conversion structure 10 comprises a first dielectric substrate 11 having a microstrip line MSL and a second dielectric substrate 14 having a post-wall waveguide PW. Here, the thickness of the first dielectric substrate 11 (first thickness) and the thickness of the second dielectric substrate 14 (second thickness) are different (the thickness of the second dielectric substrate 14 is greater than the thickness of the first dielectric substrate 11).

[0020] The thickness of the first dielectric substrate 11 may be interpreted as the thickness of the dielectric material constituting the first dielectric substrate 11 or the thickness of the microstrip line MSL, and the thickness of the second dielectric substrate 14 may be interpreted as the thickness of the dielectric material constituting the second dielectric substrate 14 or the thickness of the post-wall waveguide PW. The first dielectric substrate 11 and the second dielectric substrate 14 may be composed of one substrate or of different substrates.

[0021] As shown in Figure 1, the microstrip line MSL includes a first dielectric substrate 11, a line conductor 12, and GND 13 (first ground conductor). Specifically, the microstrip line MSL is composed of opposing line conductors 12 and GND 13 that sandwich the dielectric on the first dielectric substrate 11.

[0022] As shown in Figure 1, the post-wall waveguide PW includes a second dielectric substrate 14, a first conductor layer 15, a second conductor layer 16, and vias (via holes) 17. Specifically, the post-wall waveguide PW is composed of opposing first conductor layers 15 and second conductor layers (waveguide wide wall or simply wide wall) 16 that sandwich the dielectric in the second dielectric substrate 14, and opposing vias (waveguide narrow wall or simply narrow wall) 17 that electrically connect these conductor layers. The vias 17 are arranged in the signal transmission direction (electromagnetic wave propagation direction (transmission direction); Y direction) at intervals of half a wavelength (λ / 2) or less of the electromagnetic wave.

[0023] As shown in Figure 2, the line conductor 12 and the first conductor layer 15 are connected on the same plane (a plane parallel to the XY plane).

[0024] As shown in Figures 1 and 2, via (via hole) 18 (first via) electrically connects GND 13 and the second conductor layer 16 (GND 13 and the second conductor layer 16 are electrically connected via via 18). Therefore, unlike existing technologies, GND 13 and the second conductor layer 16 are not connected on the same plane (a plane parallel to the XY plane).

[0025] <Comparative Example> Figure 3 is a perspective view showing a mode conversion structure 30 related to a comparative example, and Figure 4 is a side cross-sectional view (A-A' cross-sectional view) showing the mode conversion structure 30. In the mode conversion structure 30, elements identical to those in the mode conversion structure 10 are given the same reference numerals, and the parts that differ from the mode conversion structure 10 will be explained.

[0026] As shown in Figures 3 and 4, the mode conversion structure 30 comprises a first dielectric substrate 11 having a microstrip line MSL and a second dielectric substrate 14 having a post-wall waveguide PW. Unlike the mode conversion structure 10, in the mode conversion structure 30, the thickness of the first dielectric substrate 11 and the thickness of the second dielectric substrate 14 are the same, the GND 13 and the second conductor layer 16 are on the same plane (XY plane), and there are no vias corresponding to vias 18. Therefore, the mode conversion structure 30 can be considered an example of existing technology based on the mode conversion structure disclosed in Patent Document 1.

[0027] <Comparison> The inventors analyzed the radiated power at 300 GHz using electromagnetic field simulations with the finite integral method for the case where a 0.1 mm thick microstrip line and a 0.2 mm thick post-wall waveguide are connected using the mode conversion structure 10 according to Embodiment 1 (Embodiment 1) shown in Figure 1, and for the case where a 0.2 mm thick microstrip line and a 0.2 mm thick post-wall waveguide are connected using the mode conversion structure 30 according to Comparative Example (Example using Existing Technology) shown in Figure 3, and compared the radiation losses.

[0028] Figure 5 shows the radiated power simulation results for the mode conversion structure 10 according to Example 1 and the mode conversion structure 30 according to the comparative example when a power of 0.5W is input. From Figure 5, it can be seen that the mode conversion structure 10 according to Example 1 radiates less power into space and reduces radiation loss compared to the mode conversion structure 30 according to Comparative Example 1. This is because the thickness of the microstrip line in Example 1 is thinner than the thickness of the microstrip line in the comparative example.

[0029] Thus, the mode conversion structure 10 does not require the thickness of the microstrip line MSL to be the same as the thickness of the post-wall waveguide PW, thereby suppressing transmission loss and enabling connection of a microstrip line MSL and a post-wall waveguide PW with different dielectric substrate thicknesses.

[0030] (Embodiment 2) <Configuration of the mode conversion structure> Figure 6 is a perspective view showing a mode conversion structure 60 according to Embodiment 2 of this disclosure, and Figure 7 is a side cross-sectional view (A-A' cross-sectional view) showing the mode conversion structure 60. In the mode conversion structure 60, elements identical to those in the mode conversion structure 10 are denoted by the same reference numerals, and parts that differ from the mode conversion structure 10 will be described.

[0031] Unlike the mode conversion structure 10, as shown in Figure 7, in the mode conversion structure 60, the GND 13, which is arranged parallel to the line conductor 12, is further extended (overlapped) by about λ / 2 between the first conductor layer 15 and the second conductor layer 16. The GND 13 extends by about λ / 2 in the direction of the post-wall waveguide PW (positive Y-axis side) with reference to the end face of the via 18 (ZX plane perpendicular to the Y-axis). When viewed from the Z direction, the via 18 is positioned about λ / 2 away (in the negative Y-axis direction) from the end face (end) of the GND 13 that is in contact with the post-wall waveguide PW, along the direction of electromagnetic wave propagation. In the mode conversion structure 60 shown in Figure 7, the GND 13, the first conductor layer 15 and the second conductor layer 16 are arranged overlapping by about λ / 2 in the YZ cross section.

[0032] As a result, the end face of GND13 (the end face that is in contact with the post-wall waveguide PW when viewed from the Z direction), via 18, and the second conductor layer 16 form a short stub, reducing power reflection and improving transmission characteristics.

[0033] <Comparison> The inventors analyzed and compared the transmission characteristics of the mode conversion structure 60 according to Example 2 (Embodiment 2) shown in Figure 6 and the mode conversion structure 30 according to the comparative example (an example using existing technology) shown in Figure 3 by electromagnetic field simulation using the finite integral method.

[0034] Figure 8 shows the simulation results of the pass-through characteristics of the mode conversion structure 60 and mode conversion structure 30. In Figure 8, the horizontal axis represents frequency (in GHz), and the vertical axis represents the value of S21, an S-parameter indicating the pass-through characteristics (in dB).

[0035] Figure 8 shows that, at a frequency of 300 GHz, the mode conversion structure 60 has better pass-through characteristics than the mode conversion structure 30.

[0036] <Variation> Figure 9 is a perspective view showing a modified mode conversion structure 90 according to Embodiment 2 of the present disclosure, and Figure 10 is a side cross-sectional view (A-A' cross-sectional view) showing the mode conversion structure 90.

[0037] In this modified example, as shown in Figure 10, the main body layer (second conductor layer) 16 is extended by approximately λ / 2 in the direction of the microstrip line MSL (negative direction of the Y axis) from the post-wall waveguide PW, with reference to the connection surface between the line conductor 12 and the first conductor layer 15 (ZX plane perpendicular to the Y axis), when viewed from the Z direction (in the XY plane). The positions of GND 13 and via 18 in the negative direction of the Y axis are shifted by approximately λ / 2 in the negative direction of the Y axis compared to the configuration of the mode conversion structure 60. In the mode conversion structure 90 shown in Figure 10, the line conductor 12, GND 13 and the second conductor layer 16 are arranged overlapping by approximately λ / 2 in the YZ cross section. In this case as well, the via 18 is positioned approximately λ / 2 away (in the negative direction of the Y axis) from the end face of GND 13 that is in contact with the post-wall waveguide PW, when viewed from the Z direction (in the XY plane), along the direction of electromagnetic wave propagation. Even with this structure, the end face of GND13 (the end face that is in contact with the post-wall waveguide PW when viewed from the Z direction), via 18, and the second conductor layer 16 form a short stub, which reduces power reflection and improves transmission characteristics.

[0038] Thus, via 18 does not have to be placed directly below or near the location where the line conductor 12 of the microstrip line MSL and the first conductor layer 15 of the post-wall waveguide PW are connected. The transmission characteristics depend on the positional relationship between the GND 13 of the microstrip line MSL, the second conductor layer 16 of the post-wall waveguide PW, and via 18.

[0039] (Embodiment 3) <Configuration of the mode conversion structure> Figure 11 is a perspective view showing a mode conversion structure 110 according to Embodiment 3 of the present disclosure, and Figure 12 is a side cross-sectional view (A-A' cross-sectional view) showing the mode conversion structure 110. In the mode conversion structure 110, elements identical to those in the mode conversion structure 60 are denoted by the same reference numerals, and the parts that differ from the mode conversion structure 60 will be described.

[0040] Unlike the mode conversion structure 60, as shown in Figures 11 and 12, the mode conversion structure 110 has a GND111 (second ground conductor) between the GND13 and the second conductor layer 16. The mode conversion structure 110 includes a GND111 positioned between the GND13 and the second conductor layer 16. Furthermore, the GND111 extends approximately 3λ / 4 along the direction of electromagnetic wave propagation from the end face of the via 18 (the end face that contacts the post-wall waveguide PW when viewed from the Z direction) when viewed from the Z direction (in the XY plane). Therefore, the end face of GND13 (the end face that contacts the post-wall waveguide PW when viewed from the Z direction) and the end face of GND111 (the end face that contacts the post-wall waveguide PW when viewed from the Z direction) are separated by approximately λ / 4 along the direction of electromagnetic wave propagation when viewed from the Z direction. In the mode conversion structure 110 shown in Figure 12, the first conductor layer 15, GND 13, and second conductor layer 16 are arranged with an overlap of approximately λ / 2 in the YZ cross-section, the first conductor layer 15, GND 111, and second conductor layer 16 are arranged with an overlap of approximately 3λ / 4 in the YZ cross-section, and GND 111 and GND 13 are arranged with an overlap of approximately λ / 2 in the YZ cross-section.

[0041] In addition, unlike the mode conversion structure 60, as shown in Figures 11 and 12, a via (via hole) 112 (second via) is provided to electrically connect GND 111 and the second conductor layer 16. The mode conversion structure 110 includes a via 112 that electrically connects GND 111 and the second conductor layer 16. The via 112 is positioned approximately λ / 2 (in the negative direction of the Y axis) away from the end face of GND 111 (the end face that is in contact with the post-wall waveguide PW when viewed from the Z direction) along the direction of electromagnetic wave propagation.

[0042] As a result, a short stub formed by GND13 and via 18, and another short stub formed by GND111 and via 112, are stacked in a stepped manner.

[0043] In this way, by arranging each short stub with a shift of approximately λ / 4, the phases of the reflected waves from each short stub can be made opposite. As a result, the reflected waves cancel each other out, reducing losses due to reflection and further improving the transmission characteristics of the mode conversion structure 110 (connection section).

[0044] <Comparison> The inventors analyzed and compared the transmission characteristics of the mode conversion structure 110 according to Embodiment 3 (Embodiment 3) shown in Figure 11 and the mode conversion structure 30 according to the comparative example (an example using existing technology) shown in Figure 3, using electromagnetic field simulation with the finite integral method.

[0045] Figure 13 shows the simulation results of the pass-through characteristics of the mode conversion structure 110 and the mode conversion structure 30. In Figure 13, the horizontal axis represents frequency (in GHz), and the vertical axis represents the value of S21 (in dB).

[0046] Figure 13 shows that, at a frequency of 300 GHz, the mode conversion structure 110 has better pass-through characteristics than the mode conversion structure 30.

[0047] <Variation> Figures 11 and 12 show an example in which the short stubs are stacked in a two-tiered staircase configuration, but there is no limit to the number of tiers. For example, as shown in Figure 14 (a side cross-sectional view showing a mode conversion structure 140 according to a modified example of Embodiment 3 of this disclosure (corresponding to the A-A' cross-sectional view in other drawings)), GND 141 and via 142 may be added, and the short stubs may be stacked in a three-tiered staircase configuration. Of course, similarly, GND and via may be added, and the short stubs may be stacked in a four-tiered or more staircase configuration.

[0048] For example, the mode conversion structure may include n (where n is an integer of 1 or more) GNDs (GND111, GND141, etc.) placed between GND13 and the second conductor layer 16, and vias (second vias; via 112, via 142, etc.) that electrically connect each of the n GNDs to the second conductor layer 16.

[0049] Furthermore, vias that electrically connect each of the n GNDs to the second conductor layer 16 may be positioned approximately λ / 2 away from each end face of the n GNDs (the end face in contact with the post-wall waveguide PW) along the direction of electromagnetic wave propagation, when viewed from the Z direction (in the XY plane). For example, as shown in Figure 14, when n=2, via 112 that electrically connects GND 111 to the second conductor layer 16 may be positioned approximately λ / 2 away from the end face of GND 111 (the end face in contact with the post-wall waveguide PW) along the direction of electromagnetic wave propagation, when viewed from the Z direction. Also, for example, via 142 that electrically connects GND 141 to the second conductor layer 16 may be positioned approximately λ / 2 away from the end face of GND 141 (the end face in contact with the post-wall waveguide PW) along the direction of electromagnetic wave propagation, when viewed from the Z direction.

[0050] Furthermore, the end faces (end faces in contact with the post-wall waveguide PW) of each (n+1) GND pair, consisting of GND13 and n GNDs, may be separated by approximately λ / 4 in the direction of electromagnetic wave propagation when viewed from the Z direction. For example, as shown in Figure 14, when n=2, the end faces (end faces in contact with the post-wall waveguide PW) of the opposing pair GND13 and GND111 may be separated by approximately λ / 4 in the direction of electromagnetic wave propagation when viewed from the Z direction. Also, for example, the end faces (end faces in contact with the post-wall waveguide PW) of the opposing pair GND111 and GND141 may be separated by approximately λ / 4 in the direction of electromagnetic wave propagation when viewed from the Z direction. In the mode conversion structure 140 shown in Figure 14, the first conductor layer 15, GND 13, and second conductor layer 16 are arranged with an overlap of approximately λ / 2 in the YZ cross-section, the first conductor layer 15, GND 111, and second conductor layer 16 are arranged with an overlap of approximately 3λ / 4 in the YZ cross-section, the first conductor layer 15, GND 141, and second conductor layer 16 are arranged with an overlap of approximately λ in the YZ cross-section, GND 111 and GND 13 are arranged with an overlap of approximately λ / 2 in the YZ cross-section, and GND 111 and GND 141 are arranged with an overlap of approximately 3λ / 4 in the YZ cross-section.

[0051] <Effects of the Embodiment> The mode conversion structures according to embodiments of this disclosure (mode conversion structures 10, 60, 90, 110, 140) include a first dielectric substrate 11 having a first thickness and a microstrip line MSL composed of opposing line conductors 12 and GND 13; a second dielectric substrate 14 having a second thickness greater than the first thickness and a post-wall waveguide PW including opposing first conductor layer 15 and second conductor layer 16; and vias 18 electrically connecting GND 13 and the second conductor layer 16. The line conductor 12 and the first conductor layer 15 are connected on the same plane (a plane parallel to the XY plane).

[0052] This configuration eliminates the need to make the thickness of the microstrip line the same as the thickness of the post-wall waveguide, thereby suppressing transmission loss and allowing connection between microstrip lines and post-wall waveguides of different thicknesses.

[0053] <Summary of Embodiments> A waveguide according to one embodiment of the present disclosure comprises a first dielectric substrate having a first thickness and having a microstrip line composed of a line conductor and a first ground conductor facing the line conductor; a second dielectric substrate having a second thickness greater than the first thickness and having a post-wall waveguide including a first conductor layer connected on the same plane as the line conductor and a second conductor layer facing the first conductor layer; and a first via electrically connecting the first ground conductor and the second conductor layer.

[0054] With the above configuration, the thickness of the microstrip line does not need to be the same as the thickness of the post-wall waveguide, thus suppressing transmission loss and enabling connection of microstrip lines and post-wall waveguides with different thicknesses.

[0055] In this mode conversion structure, the first via is positioned approximately half a wavelength away from the end of the first ground conductor that is in contact with the post-wall waveguide, along the propagation direction of the electromagnetic wave propagating through the post-wall waveguide, when viewed from a direction perpendicular to the coplane.

[0056] With the above configuration, the end of the first ground conductor, the first via, and the second conductor layer form a short stub, which reduces power reflection and improves transmission characteristics.

[0057] The mode conversion structure further comprises a second ground conductor disposed between the first ground conductor and the second conductor layer, and a second via electrically connecting the second ground conductor and the second conductor layer, wherein the second via is positioned approximately half a wavelength away from the end of the second ground conductor in contact with the post-wall waveguide, along the propagation direction, when viewed from a direction perpendicular to the coplane, and the end of the first ground conductor in contact with the post-wall waveguide and the end of the second ground conductor in contact with the post-wall waveguide are approximately one-quarter of a wavelength apart from the electromagnetic wave, when viewed from a direction perpendicular to the coplane.

[0058] With the above configuration, short stubs are stacked, and reflected waves from the short stubs are canceled out, thus reducing losses due to reflection and further improving transmission characteristics.

[0059] The mode conversion structure further comprises n ground conductors (where n is an integer of 1 or more) arranged between the first ground conductor and the second conductor layer, and a second via that electrically connects each of the n ground conductors to the second conductor layer, wherein the second via is positioned approximately half a wavelength away from the electromagnetic wave along the propagation direction, when viewed from a direction perpendicular to the coplane, from each end of the n ground conductors that are in contact with the post-wall waveguide.

[0060] With the above configuration, a short stub is formed, which reduces power reflection and improves transmission characteristics.

[0061] In this mode conversion structure, of the (n+1) pairs of opposing ground conductors, including the first ground conductor and the n ground conductors, each end in contact with the post-wall waveguide is located approximately one-quarter wavelength away from the electromagnetic wave when viewed from a direction perpendicular to the coplane.

[0062] With the above configuration, reflected waves from the short stub are canceled out, thus reducing losses due to reflection and further improving transmission characteristics.

[0063] In this mode conversion structure, when viewed from a direction perpendicular to the same plane, the first ground conductor, the first conductor layer, and the second conductor layer are arranged along the propagation direction of the electromagnetic waves propagating through the post-wall waveguide, overlapping by approximately half a wavelength of the electromagnetic waves.

[0064] In this mode conversion structure, when viewed from a direction perpendicular to the same plane, the first ground conductor, the line conductor, and the second conductor layer are arranged along the propagation direction of the electromagnetic waves propagating through the post-wall waveguide, overlapping by approximately half a wavelength of the electromagnetic waves.

[0065] While embodiments have been described above with reference to the drawings, this disclosure is not limited to such examples. It will be apparent to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims. Such modifications or alterations are also understood to fall within the technical scope of this disclosure. Furthermore, the components in the embodiments may be combined in any way without departing from the spirit of this disclosure.

[0066] All disclosures in the specification, drawings, and abstract contained in the Japanese application 2022-085966, filed on 26 May 2022, are incorporated herein by reference. [Industrial applicability]

[0067] One embodiment of the present disclosure is useful for a mode conversion structure for connecting a microstrip line and a post-wall waveguide. [Explanation of Symbols]

[0068] 10 Mode Conversion Structure 11. First dielectric substrate 12 Track conductors 13 Ground conductor 14. Second dielectric substrate 15. First Conductor Layer 16. Second Conductor Layer 17 Beer (Beer Hall) 18 Beer (Beer Hall) 30 Mode Conversion Structure 60 Mode Conversion Structure 90 Mode Conversion Structure 110 Mode Conversion Structure 111 Ground conductor 112 Beer (Beer Hall) 140 Mode Conversion Structure 141 Ground conductor 142 Beer (Beer Hall)

Claims

1. A first dielectric substrate having a first thickness and having a microstrip line composed of a line conductor and a first ground conductor facing the line conductor, A second dielectric substrate having a post-wall waveguide including a first conductor layer connected on the same plane as the aforementioned line conductor, and a second conductor layer facing the first conductor layer, and having a second thickness greater than the first thickness, A first via electrically connects the first ground conductor and the second conductor layer, Equipped with, The first via is positioned, when viewed from a direction perpendicular to the coplane, at a distance of approximately half a wavelength of the electromagnetic wave propagating through the post-wall waveguide from the end of the first ground conductor that is in contact with the post-wall waveguide, along the propagation direction of the electromagnetic wave. Mode conversion structure.

2. A second ground conductor is disposed between the first ground conductor and the second conductor layer, A second via electrically connects the second ground conductor and the second conductor layer, Furthermore, The second via is positioned approximately half a wavelength away from the end of the second ground conductor that is in contact with the post-wall waveguide, along the propagation direction, when viewed from a direction perpendicular to the coplane, The end of the first ground conductor in contact with the post-wall waveguide and the end of the second ground conductor in contact with the post-wall waveguide are separated by approximately one-quarter wavelength of the electromagnetic wave when viewed from a direction perpendicular to the same plane. The mode conversion structure according to claim 1.

3. n ground conductors (where n is an integer of 1 or more) are arranged between the first ground conductor and the second conductor layer, A second via electrically connects each of the n ground conductors to the second conductor layer, Furthermore, The second via is positioned, when viewed from a direction perpendicular to the coplane, at a distance of approximately half a wavelength of the electromagnetic wave from each end of the n ground conductors in contact with the post-wall waveguide, along the propagation direction. The mode conversion structure according to claim 1.

4. Of the ends of each opposing pair of ground conductors of the (n+1) ground conductors, including the first ground conductor and the n ground conductors, each end in contact with the post-wall waveguide is located approximately one-quarter wavelength away from the electromagnetic wave when viewed from a direction perpendicular to the coplane. The mode conversion structure according to claim 3.

5. A first dielectric substrate having a first thickness, having a microstrip line composed of a line conductor and a first ground conductor facing the line conductor, A second dielectric substrate having a post-wall waveguide including a first conductor layer connected on the same plane as the aforementioned line conductor, and a second conductor layer facing the first conductor layer, and having a second thickness greater than the first thickness, A first via electrically connects the first ground conductor and the second conductor layer, Equipped with, Viewed from a direction perpendicular to the same plane, the first ground conductor, the first conductor layer, and the second conductor layer are arranged along the propagation direction of the electromagnetic waves propagating through the post-wall waveguide, with an overlap of approximately half a wavelength of the electromagnetic waves. Mode conversion structure.

6. A first dielectric substrate having a first thickness, having a microstrip line composed of a line conductor and a first ground conductor facing the line conductor, A second dielectric substrate having a post-wall waveguide including a first conductor layer connected on the same plane as the aforementioned line conductor, and a second conductor layer facing the first conductor layer, and having a second thickness greater than the first thickness, A first via electrically connects the first ground conductor and the second conductor layer, Equipped with, Viewed from a direction perpendicular to the same plane, the first ground conductor, the line conductor, and the second conductor layer are arranged along the propagation direction of the electromagnetic waves propagating through the post-wall waveguide, with an overlap of approximately half a wavelength of the electromagnetic waves. Mode conversion structure.

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