TW202207517A - Waveguide with Flexible Substrate - Google Patents

Abstract

This waveguide with a flexible substrate includes a waveguide provided with a slit and a flexible substrate, wherein the flexible substrate is provided along an outer surface of the waveguide such that a part of the flexible substrate overlaps the slit, and a high frequency signal propagating from the slit through the waveguide is input to the flexible substrate.

Description

Waveguide with Flexible Substrate

The present disclosure relates to a waveguide with a flexible substrate.

In the next-generation 5G (5th Generation: 5th generation) system of wireless broadband communication, radio waves of millimeter-band bandwidth are used.

As a mechanism for transmitting radio waves in a millimeter-wavelength band, for example, a waveguide is used (Patent Document 1, Patent Document 2). [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 08-195605 Patent Document 2: Japanese Patent Laid-Open No. 2017-228839

[Problems to be Solved by Invention]

The high-frequency signal transmitted from the base station through the waveguide, for example, is input to the circuit board, etc., and is radiated to the outside through the antenna. When a high-frequency signal is input from the waveguide to the circuit board, efficient transmission is desired. Moreover, the use of a flexible substrate as a circuit board is considered.

The present disclosure provides a technology for inputting a high-frequency signal propagating through a waveguide to a flexible substrate. [Technical means to solve problems]

The present disclosure relates to a waveguide with a flexible substrate, which includes a waveguide with a slit, and a flexible substrate. The flexible substrate is partially overlapped with the slit. The outer surface is arranged, and the high-frequency signal propagating through the waveguide is input from the slot. [Effect of invention]

According to the present disclosure, it is possible to provide a technology for inputting a high-frequency signal propagating through a waveguide to a flexible substrate.

Hereinafter, the form for implementing this invention is demonstrated with reference to drawings. In the following drawings, the same or corresponding components are marked with the same or corresponding symbols, and the repeated description is omitted. In addition, for easy understanding, the scale of each part in the drawings may be different from the actual one. Parallel, right-angle, orthogonal, horizontal, vertical, up-down, left-right and other directions allow deviations to the extent that the effect of the embodiment is not impaired. The shape of the corners is not limited to a right angle, and may be arcuate with roundness. Parallel, right angle, orthogonal, horizontal and vertical may also include substantially parallel, substantially right angle, substantially orthogonal, substantially horizontal and substantially vertical.

"First Embodiment" <Waveguide 1 with Flexible Board> The flexible substrate-attached waveguide 1 of the first embodiment is connected to the high-frequency signal propagating through the waveguide 20 by winding the flexible substrate 30 around the waveguide 20 . The flexible substrate 30 is disposed along the outer surface 20s1 of the waveguide 20 by winding the flexible substrate 30 around the waveguide 20 . FIG. 1 is a perspective view of a waveguide 1 with a flexible substrate according to the first embodiment. FIG. 2 is a perspective view of the waveguide 20 to which the flexible substrate 30 is attached according to the first embodiment. FIG. 3 is a cross-sectional view of the waveguide 1 with a flexible substrate according to the first embodiment.

In addition, for the convenience of description, the XYZ orthogonal coordinate system is set in the figure. Regarding the coordinate axis perpendicular to the paper surface of the drawing, the cross mark in the coordinate axis circle indicates that the depth side is positive relative to the paper surface, and the black circle mark in the circle indicates that the front side is positive relative to the paper surface. However, the coordinate system is defined for the purpose of description, and the posture of the flexible substrate or the waveguide is not limited. In addition, in the present disclosure, unless otherwise specified, the Z axis is the extending direction of the waveguide 20 , and the X axis and the Y axis are the directions perpendicular to the extending direction of the waveguide 20 .

The waveguide 1 with a flexible substrate according to the first embodiment is used to transmit radio waves of the millimeter-band bandwidth used in the next-generation 5G system. For example, the still-pipe 20 is connected from the base station to an antenna provided in the space where the user is located.

The antenna may also be, for example, a patch antenna or a dipole antenna formed of a flexible substrate. In addition, the antenna may also be a slot antenna which is slotted in the waveguide. Furthermore, other waveguides can also be connected to the end of the waveguide 20 . For example, other waveguides may also be connected via a flexible substrate.

The bandwidth of the radio wave transmitted by the waveguide 20 of the first embodiment is, for example, 27.5 GHz to 29 GHz. For example, the center frequency is 28 GHz. This bandwidth is allocated for use by various operators every 400 MHz. In addition, the bandwidth is not limited to 27.5 GHz to 29 GHz, for example, the bandwidth centered on 26 GHz or 39 GHz may be used. In addition, the bandwidth is not limited to the millimeter waveband, and other frequency bands may also be used.

The waveguide with flexible substrate 1 according to the first embodiment includes a waveguide 20 and a flexible substrate 30 whose ends are short-circuited by the closing member 10 . Each element of the waveguide with flexible substrate 1 will be described.

[waveguide 20] The waveguide 20 is a waveguide that serves as a waveguide for propagation of radio waves in the millimeter-band bandwidth. The waveguide 20 is a cylindrical tube extending in the direction of propagation of the electric wave. In addition, in FIG. 3, the direction in which the radio wave propagates is a Z direction.

The waveguide 20 includes a dielectric tube 21 and a metal coating 22 covering the outer side of the dielectric tube 21 .

The dielectric tube 21 is a member that functions as a transmission path for propagation of radio waves. In the waveguide 20 , the electric wave is propagated by the dielectric tube 21 .

The dielectric tube 21 is formed of a dielectric material such as a fluorine-based resin. As the fluorine-based resin, polytetrafluoroethylene (PTFE (Polytetrafluoroethylene)) or perfluoroalkoxy alkane (PFA (Perfluoroalkoxy alkane)) can be used.

In addition, for example, when the bandwidth is 28 GHz, the outer diameter of the waveguide 20 is preferably 5 mm˜9 mm. The outer diameter of the dielectric tube 21 is smaller than that of the waveguide 20 by 1 mm to 2 mm.

The metal covering 22 is the member that defines the transmission path. The metal coating 22 is formed of a conductive member such as copper. The metal coating 22 is formed by, for example, plating. In addition, the metal coating 22 is not limited to being formed by plating, and for example, the metal coating 22 may be formed by winding a copper foil or a metal mesh. In addition, the outer side of the metal coating 22 of the waveguide 20 may be further provided with a coating of an insulating material.

The +Z side end of the waveguide 20 is closed by the closing member 10 . The closing member 10 is formed of a conductive member such as copper or the like. The closing member 10 is mechanically or electrically connected to the metal coating 22 of the waveguide 20 by, for example, soldering, soldering, applying conductive paste, or the like. The end of the waveguide 20 is short-circuited by closing the waveguide 20 with the closing member 10 .

The waveguide 20 has a slit 20p on the outer surface 20s1 of the waveguide 20 . The slit 20p is used as a passage path for guiding the electric wave propagating inside the waveguide 20 to the outside. The slit 20p is disposed at a position away from the short-circuit surface of the waveguide 20 by a quarter of the wavelength. Specifically, on the short-circuit surface of the inner surface of the self-closing member 10, the center of the slit 20p is provided at a position away from a quarter of the wavelength in the longitudinal direction (-Z direction) of the waveguide 20.

[Flexible substrate 30] The flexible substrate 30 is, for example, a circuit substrate that processes high-frequency signals transmitted from the base station via the waveguide 20 . On the flexible substrate 30, a circuit or a waveguide for propagating high-frequency signals is formed. For example, as a line, a microstrip line or a coplanar line can be used, and as a waveguide, a substrate integrated waveguide (SIW (substrate integrated waveguide)) can be used.

The flexible substrate 30 may be flexible enough to be wound around a cylindrical waveguide without resistance. The thickness of the flexible substrate 30 is preferably 0.012 mm or more and 0.8 mm or less. By thinning the flexible substrate 30, the flexibility of the flexible substrate 30 can be improved. In addition, the dielectric of the flexible substrate 30 is formed of fluorine-based resin, liquid crystal, polyimide, or the like. As the fluorine-based resin, for example, perfluoroalkoxyalkane (PFA) can be used.

The flexible substrate 30 may also include an amplifier on the substrate. In addition, the flexible substrate 30 may include an antenna such as a patch antenna or a dipole antenna.

(Connection between the waveguide 20 and the flexible substrate 30) FIG. 4 is an enlarged cross-sectional view of the connection portion between the waveguide 20 and the flexible substrate 30 of the waveguide 1 with flexible substrate according to the first embodiment. In addition, FIG. 4 shows the state before the flexible substrate 30 is wound and attached to the waveguide 20 .

An example in which the flexible substrate 30 constitutes a substrate-integrated waveguide (SIW) will be described. The flexible substrate 30 includes an upper surface conductive layer 31 , a lower surface conductive layer 32 , and a dielectric layer 33 sandwiched between the upper surface conductive layer 31 and the lower surface conductive layer 32 . The upper surface conductive layer 31 has a slot hole 30p. The slot hole 30p and the slit 20p of the waveguide 20 have substantially the same shape. Further, the flexible substrate 30 includes a through hole 35 connecting the upper surface conductive layer 31 and the lower surface conductive layer 32 . Therefore, the upper surface conductive layer 31 and the lower surface conductive layer 32 of the flexible substrate 30 have the same potential.

As shown in FIG. 4 , when connecting the waveguide 20 and the flexible substrate 30 , the positions of the slits 20 p of the waveguide 20 and the slots 30 p of the flexible substrate 30 are aligned. And, it is mounted by winding both sides of the slot 30 p of the flexible substrate 30 around the waveguide 20 . During winding, for example, a conductive paste may be applied, or a conductive adhesive may be used for bonding. By winding the flexible substrate 30 around the waveguide 20 , a portion of the flexible substrate 30 overlaps with the slit 20 p of the waveguide 20 . Furthermore, by winding the flexible substrate 30 around the waveguide 20 , the flexible substrate 30 is provided along the outer surface of the waveguide 20 . In addition, by bringing the metal coating 22 of the waveguide 20 into contact with the conductive layer 31 on the upper surface of the flexible substrate 30, the leakage of radio waves from the gap 20p can be prevented.

(Propagation characteristics of radio waves from the waveguide 20 to the flexible substrate 30 ) The propagation characteristics of the radio wave propagating from the waveguide 20 to the flexible substrate 30 will be described.

FIG. 5 is a diagram showing an analytical model for analyzing the propagation characteristics of the waveguide with flexible substrate 1 according to the first embodiment.

The waveguide MP is a waveguide corresponding to a portion of the waveguide 20 in which the electric wave propagates. In addition, in FIG. 5, the extending direction of the waveguide MP is set as the Y-axis. In addition, let the directions perpendicular to the extending direction of the waveguide MP be the X axis and the Y axis. The waveguide MP was modeled to form the following waveguides: the inner diameter was 6 mm, the outer diameter was 7 mm, and 0.01 mm copper was wound around a polytetrafluoroethylene (PTFE) tube. The waveguide MP enters the radio wave from the incident surface SI. In this analysis, the polarized wave in the Z direction (quasi-TE11 mode) is incident from the incident surface SI. Moreover, the reflection surface SR is formed in the waveguide MP. The radio wave incident from the incident surface SI propagates in the +Y direction in the waveguide MP, and is reflected by the reflection surface SR. In addition, the reflection surface SR is a short-circuit surface. A slot SL is provided in the +X direction of the waveguide MP. The radio waves in the waveguide MP are output from the slot SL to the outside of the waveguide MP. In addition, the center of the slit SL is provided at a position separated from the reflection surface SR by a quarter of the wavelength of the radio wave in the -Y direction. In this analysis, the wavelength of the radio wave is set to the frequency of the radio wave as 28 GHz, the distance from the center of the slot SL to the reflecting surface in the Y-axis direction is set to 5 mm, the length of the slot SL in the Y-axis direction is 4.35 mm, and the width is 4.35 mm. (The length along the outer periphery of the waveguide MF on the plane perpendicular to the Y-axis) is 0.9 mm.

The waveguide MF is a waveguide corresponding to a portion of the flexible substrate 30 where the radio wave propagates. The waveguide MF was modeled to form a substrate-integrated waveguide (SIW) fabricated in a flexible substrate with a width of 4.5 mm and a thickness of 0.2 mm. The waveguide MF injects radio waves from the slot SL, and propagates the radio waves inside the waveguide MF. In addition, the slot SL is used as a slot hole of a substrate-integrated waveguide (SIW). In addition, an aperture rod IP (Iris post) is provided in the middle of the waveguide of the flexible substrate. The length of each of the aperture rods IP in the Y-axis direction is 0.9 mm, and the width (the length along the outer periphery of the waveguide MF on the plane perpendicular to the Y-axis) is 0.25 mm. The waveguide MF injects radio waves from the slot SL (slot hole). The radio wave incident from the slot SL (slot hole) propagates in the waveguide MF and is output from the output surface SO. In this analysis, the radio wave in the TE10 mode of the output surface SO is analyzed.

FIG. 6 is a diagram showing the results of analysis of the propagation characteristics of the waveguide with the flexible substrate according to the first embodiment. The horizontal axis represents frequency. The vertical axis represents transmission coefficient and reflection coefficient in decibels. The transmission coefficient T1 represents the ratio of the intensity of radio waves emitted from the exit surface SP to the intensity of radio waves incident from the incident surface SI. The reflection coefficient R1 represents the ratio of the intensity of the radio waves reflected to the incident surface SI without being emitted from the exit surface SO to the intensity of the radio waves incident from the incident surface SI.

According to the result of FIG. 6, by setting the position of the slot SL at a position separated from the reflection surface SR by a quarter of the wavelength of the electric wave, the electric wave from the waveguide MP can be transmitted to the waveguide MF. As a result of the above, by arranging along the outer surface 20s1 of the waveguide 20 so as to overlap with the slit 20p of the waveguide 20, the electric wave can be transmitted from the waveguide 20 to the flexible substrate 30.

(Effect) In the waveguide with flexible substrate 1 according to the first embodiment, the flexible substrate 30 is provided along the outer surface 20s1 of the waveguide 20 so as to overlap with the slit 20p of the waveguide 20, so that the flexible substrate 30 can be The high-frequency signal propagating through the waveguide 20 is input to the flexible substrate 30 .

"Second Embodiment" <Waveguide 2 with Flexible Board> The flexible substrate-attached waveguide 2 of the second embodiment is connected to the high-frequency signal propagating through the waveguide 20 by winding the flexible substrate 130 around the waveguide 20 several times. The flexible substrate 130 is disposed along the outer surface 20s1 of the waveguide 20 by winding the flexible substrate 130 around the waveguide 20 . FIG. 7 is a cross-sectional view of the waveguide 2 with a flexible substrate according to the second embodiment. FIG. 8 is an enlarged cross-sectional view of a connecting portion of the waveguide 2 with a flexible substrate according to the second embodiment. In addition, FIG. 8 expands and shows the flexible substrate 130 wound around the waveguide 20 . In addition, in FIG. 8, in order to demonstrate the state in which the flexible board|substrate 130 is wound several times, the flexible board|substrate 130 is enlarged and illustrated with respect to the waveguide 20. As shown in FIG.

The flexible substrate-attached waveguide 2 of the second embodiment is wound around the flexible substrate 130 several times around the waveguide 20 . Specifically, the stacking is performed five times at the slot 20p of the waveguide 20 . In addition, the number of times of winding is not limited to 5, and may be 2 or more.

[Flexible substrate 130] The flexible substrate 130 is formed with a microstrip line 130d as a wiring. The flexible substrate 130 includes an upper surface conductive layer 131 , a lower surface conductive layer 132 , and a dielectric layer 133 sandwiched between the upper surface conductive layer 131 and the lower surface conductive layer 132 . Moreover, in order to connect the upper surface conductive layer 131 and the lower surface conductive layer 132, the through hole 135 is provided. In addition, in FIG. 8, the number of the layer laminated|stacked in the position of the slit 20p of the waveguide 20 is shown by the number in parenthesis. For example, the upper surface conductive layer 131 of the first layer of the flexible substrate 130 in contact with the waveguide 20 is shown as the upper surface conductive layer 131(1). Similarly, the upper surface conductive layer 131, the lower surface conductive layer 132, and the dielectric layer 133 of the nth layer are respectively shown as the upper surface conductive layer 131(n), the lower surface conductive layer 132(n), and the dielectric layer 133(n). ).

The flexible substrate 130 is laminated several times in the gap 20p. The flexible substrate 130 has a connecting portion 130a which removes a part of the upper surface conductive layer 131(1) of the first layer to expose the first dielectric layer 133(1). The slit 20p of the waveguide 20 is in contact with the connecting portion 130a. In addition, a microstrip line 130d is formed on the lower surface conductive layer 132(1) of the first layer on the opposite side of the dielectric layer 133(1) at the portion where the gap 20p of the insulating waveguide 20 contacts. In addition, in the portions of the second to fourth layers corresponding to the connecting portions 130a, the upper surface conductive layer 131 and the lower surface conductive layer 132 are removed, and the dielectric layer 133 is exposed. That is, the upper surface conductive layer 131 ( 2 ), the upper surface conductive layer 131 ( 3 ), the upper surface conductive layer 131 ( 4 ), the lower surface conductive layer 131 ( 4 ), the lower surface conductive layer 131 ( 4 ), the lower surface conductive layer 131 ( 2 ), the upper surface conductive layer 131 ( 3 ), the upper surface conductive layer Conductive layer 132(2), lower surface conductive layer 132(3), lower surface conductive layer 132(4). On the portion of the fifth layer corresponding to the connection portion 130a, an upper surface conductive layer 131(5) and a lower surface conductive layer 132(5) are formed. The upper surface conductive layer 131(5) serves as a reflection surface 130b that reflects the radio waves incident from the connection portion 130a.

By winding the flexible substrate 130 around the waveguide 20 , the flexible substrate 130 is disposed along the outer surface of the waveguide 20 . At the time of winding, for example, a conductive paste can be applied or bonded with a conductive adhesive. In addition, by bringing the metal coating 22 of the waveguide 20 into contact with the first-layer upper surface conductive layer 131(1) of the flexible substrate 130, the leakage of the electric wave from the gap 20p can be prevented.

FIGS. 9 and 10 show the flexible substrate 130 on which the laminated structure shown in FIG. 8 is formed. FIG. 9 is a plan view of the expanded flexible substrate 130 of the second embodiment. FIG. 10 is a bottom view of the expanded flexible substrate 130 of the second embodiment.

The region RT1 , the region RT2 , the region RT3 , and the region RT4 represent the regions where the upper surface conductive layer 131 of the flexible substrate 130 has been removed. The region RT1 corresponds to the region of the connection portion 130a. The region RT2 , the region RT3 , and the region RT4 are regions corresponding to the connection portion 130 a when the flexible substrate 130 is wound around the waveguide 20 . In addition, the upper surface conductive layer 131 has also been removed in the region of the region RT2 that overlaps with the wiring portion of the microstrip line 130d. The region RT5 represents a portion where the upper surface conductive layer 131 of the fifth layer is provided and becomes the reflection surface 130b. In addition, the area|region RT1, the area|region RT2, the area|region RT3, the area|region RT4, and the area|region RT5 are provided at intervals corresponding to the circumference of the waveguide 20 .

The region RB1 , the region RB2 , the region RB3 , and the region RB4 represent the regions from which the lower surface conductive layer 132 of the flexible substrate 130 has been removed. The region RB1 is a region where the microstrip line 130d is formed. The region RB2 , the region RB3 , and the region RB4 are regions corresponding to the connection portion 130 a when the flexible substrate 130 is wound around the waveguide 20 . The region RT5 represents the portion of the lower surface conductive layer 132 provided with the fifth layer outside the reflective surface 130b. In addition, the area|region RB1, the area|region RB2, the area|region RB3, the area|region RB4, and the area|region RB5 are provided with the space|interval corresponding to the circumference of the waveguide 20, and are provided.

The part corresponding to the connection part 130a is demonstrated. The actual thickness of the upper surface conductive layer 131 and the lower surface conductive layer 132 is about 20 μm, while the actual thickness of the dielectric layer 133 is 200 μm. Furthermore, by winding the flexible substrate 130 around the waveguide 20 , the layers of the laminated flexible substrate 130 are adhered to each other. That is, the portion corresponding to the connection portion 130a between the lower surface conductive layer 132(1) of the first layer and the upper surface conductive layer 131(5) of the fifth layer is the dielectric layer 133(2), the dielectric layer 133( 3), the dielectric layer 133 (4) is adhered and laminated. In addition, in FIG. 8, in order to clarify the relationship between the layers, it is shown with a gap between the layers. Therefore, the outer side of the microstrip line 130d can be regarded as a layer in which a plurality of layers of dielectric layers 133 are laminated, specifically, a layer in which three layers are laminated.

The distance L1 between the microstrip line 130d and the reflective surface 130b can be lengthened by laminating the dielectric layers 133 several times.

Electromagnetic field analysis was performed on the waveguide 2 with a flexible substrate according to the second embodiment. For analysis, the size of the slit 20p of the waveguide 20 is set to be 5.4 mm in length and 0.5 mm in width, the flexible substrate 130 is set as a fluororesin substrate with a thickness of 0.2 mm, the conductive layer is made of copper, and the line width is set to 0.2 mm , and the analysis was carried out by setting the distance L1 of the resonator 130c to 2.5 mm.

FIG. 11 is a diagram showing the results of analysis of the propagation characteristics of the waveguide 2 with the flexible substrate according to the second embodiment. The horizontal axis represents frequency. The vertical axis represents transmission coefficient and reflection coefficient in decibels. The transmission coefficient T2 represents the ratio of the intensity of the electric wave transmitted through the microstrip line 130 d to the intensity of the electric wave of the Y-direction polarized wave (quasi-TE11 mode) incident on the waveguide 20 in FIG. 7 . The reflection coefficient R2 represents the ratio of the intensity of the reflected electric wave not incident on the microstrip line 130d to the electric wave intensity of the Y-direction polarized wave (quasi-TE11 mode) incident on the waveguide 20 in FIG. 7 .

As can be seen from the results in FIG. 11 , when the frequency is 28 GHz, the signal is efficiently propagated from the waveguide 20 to the microstrip line 130d.

"Third Embodiment" <Waveguide 3 with Flexible Board> The flexible substrate-attached waveguide 3 of the third embodiment is connected to the high-frequency signal propagating through the waveguide 220 by winding the flexible substrate 230 around the waveguide 220 . In the waveguide 3 with a flexible substrate according to the third embodiment, radio waves are incident on the flexible substrate 230 from the slits 220p1 and 220p2 provided at the second part of the waveguide 220 . FIG. 12 is a cross-sectional view of the waveguide 3 with a flexible substrate according to the third embodiment.

The waveguide 220 includes a dielectric tube 221 and a metal coating 222 covering the outside of the dielectric tube 221 .

The dielectric tube 221 is a member that functions as a transmission path for propagation of radio waves. In the waveguide 220 , the electric wave is propagated by the dielectric tube 221 . The metal covering 222 is the member that defines the transmission path. The materials of the dielectric tube 221 and the metal coating 222 are the same as those of the dielectric tube 21 and the metal coating 22 of the waveguide 20 .

The waveguide 220 is provided with a plurality of slits. Specifically, the waveguide 220 has two slits 220p1 and 220p2. The slit 220p1 and the slit 220p2 are passage paths for guiding the radio waves propagating inside the waveguide 220 to the outside. The slot 220p1 and the slot 220p2 are disposed at positions separated from the short-circuit surface of the waveguide 220 by a quarter of the wavelength.

A radio wave is input to the flexible substrate 230 from two places of the slit 220p1 and the slit 220p2. It is the same as the flexible substrate 30 and the flexible substrate 130 except that it is input from two places.

The flexible substrate 230 can convert the polarization in the two directions by inputting the polarized wave (quasi-TE11 mode) in the Y direction from the slit 220p1 and inputting the radio wave of the polarized wave in the X direction (quasi-TE11 mode) from the slit 220p2. Wave.

<Action, effect> According to the waveguide with the flexible substrate including the waveguide and the flexible substrate of the present disclosure, the high-frequency signal propagating through the waveguide can be input to the flexible substrate. The waveguide with flexible substrate of the present disclosure can be fabricated by winding the flexible substrate around the waveguide.

<Variation example> The shape of the waveguide is not limited to a cylindrical shape. For example, the waveguide may also be in the shape of a cube. In addition, a cavity may be provided inside the waveguide, and when the metal coating can stand on its own, there may be no dielectric tube.

"4th Embodiment" <Waveguide 4 with Flexible Board> The flexible substrate-attached waveguide 4 of the fourth embodiment is connected to the high-frequency signal propagating through the waveguide 320 by winding the flexible substrate 330 around the waveguide 320 . In the waveguide 4 with a flexible substrate according to the fourth embodiment, the flexible substrate 330 is connected to the waveguide 320 via the conductive adhesive 350 . FIG. 13 is a cross-sectional view of the waveguide 4 with a flexible substrate according to the fourth embodiment.

The waveguide 320 includes a metal coating 322 . The metal covering 322 is the member that defines the transmission path. Since the metal coating 322 can maintain its shape independently, the inside becomes the cavity 321 . That is, in the waveguide 320 , the radio wave propagates in the air of the cavity 321 . In addition, a dielectric tube can also be provided in the cavity 321 to replace the air in the cavity 321 . In addition, the material and the like of the metal coating 322 are the same as those of the metal coating 22 of the waveguide 20 .

The waveguide 320 includes a slit 320p. The radio wave propagating through the cavity 321 is incident on the flexible substrate 330 from the slit 320p.

The flexible substrate 330 constitutes a substrate-integrated waveguide (SIW). The flexible substrate 330 includes an upper surface conductive layer 331 , a lower surface conductive layer 332 , and a dielectric layer 333 sandwiched between the upper surface conductive layer 331 and the lower surface conductive layer 332 . In addition, in order to connect the upper surface conductive layer 331 and the lower surface conductive layer 332, the flexible substrate 330 is provided with a through hole (not shown). Therefore, the upper surface conductive layer 331 and the lower surface conductive layer 332 of the flexible substrate 330 have the same potential.

The upper surface conductive layer 531 has a slot having substantially the same shape as the slot 320p. The electric wave from the slit 320p is introduced into this slot.

A conductive adhesive 350 is coated on the outer surface of the metal coating 322 . The conductive adhesive 350 is, for example, an anisotropic conductive film in which fine metal particles are mixed in resin. The conductive adhesive 350 is applied to avoid the gap 320p so as not to block the gap 320p. Moreover, the conductive adhesive 350 is apply|coated so that the slit 320p may be enclosed.

The conductive adhesive 350 is applied, the flexible substrate 330 is wound around the waveguide 320 , and the conductive adhesive 350 is cured. The flexible substrate 330 is fixed to the waveguide 320 by curing the conductive adhesive 350 . By fixing the waveguide 320 and the flexible substrate 330 with the conductive adhesive 350 , the metal coating 322 and the conductive layer 331 on the upper surface of the flexible substrate 330 can be electrically connected.

In addition, by applying the conductive adhesive 350 so as to surround the gap 320p, leakage of electromagnetic waves from the vicinity of the gap 320p can be suppressed.

"Fifth Embodiment" <Waveguide 5 with Flexible Board> The flexible substrate-attached waveguide 5 of the fifth embodiment is connected to the high-frequency signal propagating through the waveguide 320 by winding the flexible substrate 330 around the waveguide 320 . In the waveguide 5 with flexible substrate according to the fifth embodiment, the flexible substrate 330 is connected to the waveguide 320 by the solder 450 . FIG. 14 is a cross-sectional view of a waveguide 5 with a flexible substrate according to the fifth embodiment.

Solder 450 is applied to the surface of the metal coating 322 opposite to the flexible substrate 330 . The solder 450 is, for example, solder paste. In order not to block the gap 320p with the solder 450, a protective sheet 460 is attached around the gap 320p. The protective sheet 460 is, for example, a polyimide tape.

FIG. 15 is a side view of the waveguide 320 of the waveguide with flexible substrate 5 according to the fifth embodiment. The protective sheet 460 is attached to the outer periphery of the slit 320p so that the solder 450 does not flow into the slit 320p so as to block the slit 320p. In addition, in order to prevent deterioration of radio wave propagation characteristics, the protective sheet 460 is desirably as narrow as possible.

A protective sheet 460 is attached to the outer periphery of the slit 320p of the metal coating 322 of the waveguide 320 . In addition, solder 450 is applied to the surface of the outer surface of the metal coating 322 of the waveguide 320 facing the flexible substrate 330 . Next, the flexible substrate 330 is wound around the waveguide 320 . Then, the waveguide 320 on which the flexible substrate 330 is wound is heated and then cooled to harden the solder 450 .

The flexible substrate 330 is fixed to the waveguide 320 by curing the solder 450 . By fixing the waveguide 320 and the flexible substrate 330 with the solder 450 , the metal coating 322 and the conductive layer 331 on the upper surface of the flexible substrate 330 can be electrically connected.

In addition, the protective sheet 460 can prevent the solder 450 from flowing into the gap 320p. In addition, by providing the solder 450 so as to surround the slit 320p, leakage of electromagnetic waves from the vicinity of the slit 320p can be suppressed.

"Sixth Embodiment" <Waveguide 6 with Flexible Board> The flexible substrate-attached waveguide 6 of the sixth embodiment is connected to the high-frequency signal propagating through the waveguide 320 by winding the flexible substrate 530 around the waveguide 320 . In the waveguide 6 with a flexible substrate according to the sixth embodiment, the flexible substrate 530 is bonded to the waveguide 320 by the solder 450 . FIG. 16 is a cross-sectional view of a waveguide 6 with a flexible substrate according to the fifth embodiment.

The flexible substrate 530 constitutes a substrate integrated waveguide (SIW). The flexible substrate 530 includes an upper surface conductive layer 531 , a lower surface conductive layer 532 , and a dielectric layer 533 sandwiched between the upper surface conductive layer 531 and the lower surface conductive layer 532 . Moreover, in order to connect the upper surface conductive layer 531 and the lower surface conductive layer 532, the flexible board|substrate 530 is provided with the via hole 530th mentioned later. Therefore, the upper surface conductive layer 531 and the lower surface conductive layer 532 of the flexible substrate 530 have the same potential.

FIG. 17 is a side view of the flexible substrate 530 of the waveguide 6 with flexible substrate according to the sixth embodiment. FIG. 17 is a side view of the flexible substrate 530 viewed from the upper surface conductive layer 531 side.

The upper surface conductive layer 531 has a slot 530p having substantially the same shape as the slit 320p. The radio wave from the slit 320p is introduced into the slot 530p. A plurality of via holes 530th are provided so as to surround the slot hole 530p. The plurality of vias 530th form the waveguide of the flexible substrate 530 . Each of the plurality of vias 530th electrically connects the upper surface conductive layer 531 and the lower surface conductive layer 532 and penetrates through the dielectric layer 533 .

A plurality of solder via holes 530sh are provided on the outer side of the plurality of via holes 530th with respect to the slot hole 530p. Each of the plurality of solder vias 530sh connects the upper surface conductive layer 531 and the lower surface conductive layer 532 and penetrates through the dielectric layer 533 . The diameter of the via hole 530sh for solder is larger than that of the via hole 530th. Solder 450 is injected from solder via hole 530sh.

The flexible substrate 530 is wound around the waveguide 320 . Then, the solder 450 is injected from the solder via hole 530sh. Next, the waveguide 320 on which the flexible substrate 530 is wound is heated and then cooled to harden the solder 450 . At this time, the solder 450 injected and heated from the solder via hole 530sh flows into the via hole 530th due to the capillary phenomenon, and does not reach the slit 320p and the slot hole 530p. Therefore, it is possible to prevent the solder 450 from clogging the slit 320p and the slot 530p.

The flexible substrate 530 is fixed to the waveguide 320 by curing the solder 450 . By fixing the waveguide 320 and the flexible substrate 530 with the solder 450 , the metal coating 322 and the conductive layer 531 on the upper surface of the flexible substrate 530 can be electrically connected.

Furthermore, by providing the solder 450 so as to surround the slit 320p, leakage of electromagnetic waves from the vicinity of the slit 320p can be suppressed.

In addition, it should be considered that all points of the embodiments disclosed this time are illustrative and not restrictive. The above-described embodiments may be omitted, replaced, and changed in various forms without departing from the scope and gist of the appended claims.

This application claims the priority of Basic Patent Application No. 2020-058876 filed with the Japan Patent Office on March 27, 2020, the entire contents of which are incorporated herein by reference.

1: Waveguide with flexible substrate 2: Waveguide with flexible substrate 3: Waveguide with flexible substrate 4: Waveguide with flexible substrate 5: Waveguide with flexible substrate 6: Waveguide with flexible substrate 10: Closing member 20: still-pipe 20p: Gap 20s1: outer surface 21: Dielectric tube 22: Metal coating 30: Flexible substrate 30p: Slots 31: Conductive layer on the upper surface 32: Conductive layer on the lower surface 33: Dielectric layer 35: Through hole 130: Flexible substrate 130a: Connection part 130b: Reflective surface 130c: Resonator 130d: Microstrip line 131: upper surface conductive layer 131(1) to 131(5): Conductive layer on the upper surface 132: Lower surface conductive layer 132(1)～132(5): Conductive layer on the lower surface 133: Dielectric layer 133(1)～133(5): Dielectric layer 135: Through hole 220: still-pipe 220p1: Gap 220p2: Gap 221: Dielectric Tube 222: Metal Coating 230: Flexible Substrate 320: still-pipe 320p: Gap 321: cavity 322: Metal Coating 330: Flexible Substrate 331: upper surface conductive layer 332: Lower surface conductive layer 333: Dielectric Layer 350: Conductive Adhesive 450: Solder 460: Protective sheet 530: Flexible Substrate 530p: Slots 530sh: Via hole for solder 530th: Via 531: upper surface conductive layer 532: Lower surface conductive layer 533: Dielectric Layer IP: Aperture lever MF: Waveguide MP: Waveguide RB1 to RB5: Area RT1～RT5: Area SI: Incident surface SL: Slit SO: exit surface SR: Reflective Surface

FIG. 1 is a perspective view of a waveguide with a flexible substrate according to the first embodiment. Fig. 2 is a perspective view of a waveguide to which a flexible substrate is mounted according to the first embodiment. Fig. 3 is a perspective view of a waveguide with a flexible substrate according to the first embodiment. Fig. 4 is an enlarged cross-sectional view of the connecting portion of the waveguide with flexible substrate according to the first embodiment. FIG. 5 is a diagram showing an analytical model for analyzing the propagation characteristics of the waveguide with the flexible substrate according to the first embodiment. FIG. 6 is a diagram showing the results of analysis of the propagation characteristics of the waveguide with the flexible substrate according to the first embodiment. Fig. 7 is a cross-sectional view of a waveguide with a flexible substrate according to a second embodiment. Fig. 8 is an enlarged cross-sectional view of a connecting portion of the waveguide with flexible substrate according to the second embodiment. FIG. 9 is a plan view of the expanded flexible substrate of the second embodiment. Fig. 10 is a bottom view of the expanded flexible substrate of the second embodiment. FIG. 11 is a diagram showing the results of analysis of the propagation characteristics of the waveguide with flexible substrate according to the second embodiment. Fig. 12 is a cross-sectional view of a waveguide with a flexible substrate according to a third embodiment. Fig. 13 is a cross-sectional view of a waveguide with a flexible substrate according to a fourth embodiment. Fig. 14 is a cross-sectional view of a waveguide with a flexible substrate according to a fifth embodiment. Fig. 15 is a side view of the waveguide with flexible substrate according to the fifth embodiment. Fig. 16 is a cross-sectional view of a waveguide with a flexible substrate according to a sixth embodiment. Fig. 17 is a side view of the flexible substrate of the waveguide with flexible substrate according to the sixth embodiment.

1: Waveguide with flexible substrate

10: Closing member

20: still-pipe

20s1: outer surface

30: Flexible substrate

Claims (8)

A waveguide with a flexible substrate, comprising: a still-pipe provided with a slit; and a flexible substrate; and The flexible substrate is disposed along the outer surface of the waveguide so that a part of the flexible substrate overlaps with the slot, and a high-frequency signal propagating through the waveguide is input from the slot. The waveguide with flexible substrate as claimed in claim 1, wherein The slot is disposed at a position separated from the short-circuit surface of the waveguide at a quarter of the wavelength of the radio wave propagating through the waveguide. The waveguide with flexible substrate as claimed in claim 1 or 2, wherein The above-mentioned flexible substrate constitutes a substrate-integrated waveguide. The waveguide with flexible substrate as claimed in claim 3, wherein The substrate-integrated waveguide includes a slot hole, and is attached so that the slot overlaps with the slot hole. The waveguide with flexible substrate as claimed in claim 1 or 2, wherein The flexible substrate described above includes a microstrip line. The waveguide with flexible substrate as claimed in claim 5, wherein The above-mentioned flexible substrate is laminated on the above-mentioned slit a plurality of times. The waveguide with flexible substrate as claimed in claim 6, wherein The flexible substrate is formed with a resonator including the microstrip line, a layer in which a plurality of dielectric layers are stacked, and a reflection surface at a portion corresponding to the slit. A waveguide with flexible substrate according to any one of claims 1 to 7, wherein A plurality of the above-mentioned slits are provided.

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