JP2023136491A - Planar line/waveguide converter - Google Patents

Abstract

To provide a planar line/waveguide converter that does not generate unnecessary propagation modes in a board while making the board width of a circuit portion and the board width of a probe part identical.SOLUTION: A planar line/waveguide converter includes at least one conductive via hole 14 that penetrates from the front surface to the back surface of a board 10 and electrically connects a front surface ground conductor 12 and a back surface ground conductor 13, a waveguide 50 in which the board 10 is inserted into a board insertion hole 54 provided in a side wall 53, and an edge 55 of the board insertion hole 54 is electrically connected to the back surface ground conductor 13, a probe 30 provided on the surface of the board 10, integrally formed with a line conductor 11, and extending into the inside of the waveguide 50, and an MMIC 40. The back surface ground conductor 13 is not provided in a region including directly below the probe 30 on the back surface of the board 10, and the conductive via hole 14 is arranged on at least one side of the line conductor 11 in the lateral direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a planar line/waveguide converter, and particularly to a planar line/waveguide converter that connects a waveguide and a planar line such as a microstrip line or a coplanar line.

Conventionally, it is used as a means of converting electrical signals transmitted on planar lines such as microstrip lines and coplanar lines formed on a dielectric substrate into electromagnetic waves transmitted in waveguides, or as a means of converting in the opposite direction. , a planar line/waveguide converter is used (for example, see Patent Document 1).

As shown in FIG. 13, the substrate planar line/waveguide converter 61 disclosed in Patent Document 1 includes a dielectric substrate 62, a coplanar line 63 provided on the dielectric substrate 62, and a dielectric substrate. a back ground conductor 64 provided on the back surface of the waveguide 62; a waveguide 65 that is erected on the dielectric substrate 62 and whose edge of the end opening on the dielectric substrate 62 side is connected to the back ground conductor 64; The waveguide excitation antenna 67 is formed by extending the end of the center conductor 66 into the waveguide 65. Furthermore, this substrate planar line/waveguide converter 61 is configured such that the thickness of the dielectric substrate 62 is set to approximately 1/4 of the wavelength within the dielectric.

Further, Patent Document 1 describes that a monolithic microwave integrated circuit (MMIC) or the like is connected to the left end side of the dielectric substrate 62.

Japanese Patent Application Publication No. 11-261312

When configuring the inside of an MMIC, a planar line, and a waveguide converter on one board, the board width of the probe part (waveguide excitation antenna 67) that induces the electromagnetic field of the waveguide should be changed between the MMIC and the planar line. If the width is not narrow relative to the substrate width of circuit parts such as lines, unnecessary propagation modes will occur within the substrate of the probe portion, and the frequency band of high-frequency signals that can be propagated from the probe to the waveguide will be narrowed. In order to prevent this, as disclosed in Patent Document 1, the substrate width of the probe portion may be narrowed to form a convex shape. However, since the width of the MMIC is small, about 1 mm, the substrate width of the probe portion has to be narrowed to about 0.3 mm to 0.5 mm. Such irregular shape machining has the problem of increasing parts machining costs and causing cracks to occur, causing reliability deterioration.

The present invention has been made in order to solve such conventional problems, and provides a planar line that does not generate unnecessary propagation modes in the board while making the board width of the circuit part and the board width of the probe part the same.・The purpose is to provide a waveguide converter.

In order to solve the above problems, a planar line/waveguide converter according to the present invention includes a substrate, a line conductor provided on the surface of the substrate, and at least one surface ground conductor provided on the surface of the substrate. a conductor, a back ground conductor provided on the back surface of the substrate, at least one conductive via hole penetrating from the front surface of the substrate to the back surface and electrically connecting the front surface ground conductor and the back surface ground conductor; The board is inserted into a provided board insertion hole, the edge of the board insertion hole is electrically connected to the back surface ground conductor, and the waveguide is provided on the surface of the board and is integrated with the line conductor. a probe that is formed and extends inside the waveguide; a signal electrode that is provided on the front side of the substrate and is electrically connected to the line conductor; and a ground that is electrically connected to the back surface ground conductor. an MMIC having an electrode, the back surface ground conductor is not provided in a region including directly below the probe on the back surface of the substrate, and the conductive via hole is provided on at least one side in the lateral direction of the line conductor. This is the configuration in which it is placed.

With this configuration, in the planar line/waveguide converter according to the present invention, a conductive via hole penetrating from the front surface to the back side of the substrate is arranged on at least one side in the lateral direction of the line conductor, so that the probe is formed at the location where the probe is formed. It is possible to create a state as if the width of the board was narrowed. As a result, in the planar line/waveguide converter according to the present invention, even when the circuit section and the probe are formed on the same substrate, the width of the substrate of the circuit section and the width of the substrate of the probe section can be made the same. At the same time, generation of unnecessary propagation modes within the substrate can be suppressed.

In other words, the planar line/waveguide converter according to the present invention maintains a wide frequency band of high-frequency signals that can be propagated from the probe to the waveguide, and also has the same substrate processing as a rectangular MMIC, so that parts can be easily processed. No increase in processing costs or deterioration of reliability.

Further, the planar line/waveguide converter according to the present invention includes at least one back conductor provided on the back surface of the substrate, and at least one back conductor provided in a region including directly above the back conductor on the front surface of the substrate. The substrate further includes one surface conductor and at least one through via hole that penetrates from the front surface to the back surface of the substrate and electrically connects the front surface conductor and the back surface conductor, and the through via hole is located at least on the side of the probe. It may be arranged on one side in the direction.

With this configuration, in the planar line/waveguide converter according to the present invention, a through via hole penetrating from the front surface to the back surface of the substrate is arranged at least on one side in the lateral direction of the probe, so that the substrate at the location where the probe is formed is arranged. It is possible to create a state in which the width of the image appears to be narrower. Thereby, the planar line/waveguide converter according to the present invention can change the radiation pattern of the probe into a desired shape.

Further, in the planar line/waveguide converter according to the present invention, at least one of the surface ground conductors and at least one of the surface conductors are integrated, and the back surface ground conductor and at least one of the back surface conductors are integrated. An integrated configuration may also be used.

With this configuration, the planar line/waveguide converter according to the present invention can prevent electromagnetic waves from passing between the via holes and direct the radiation direction of electromagnetic waves from the probe in a desired direction.

Further, the planar line/waveguide converter according to the present invention includes a substrate, a line conductor provided on the surface of the substrate, at least one surface ground conductor provided on the surface of the substrate, and a surface ground conductor provided on the surface of the substrate. The board is inserted into a back ground conductor provided on the back surface, a through hole penetrating from the front surface of the board to the back surface, and a board insertion hole provided in the side wall, and the edge of the board insertion hole is connected to the back ground conductor. a waveguide electrically connected to the substrate, a probe provided on the surface of the substrate, integrally formed with the line conductor, and extending into the waveguide; an MMIC having a signal electrode electrically connected to a line conductor and a ground electrode electrically connected to the back surface ground conductor, and in a region including directly below the probe on the back surface of the substrate, The back surface ground conductor may not be provided, and the through hole may be arranged at least on one side in the lateral direction of the line conductor and the probe.

With this configuration, in the planar line/waveguide converter according to the present invention, the probe is formed by disposing a through hole penetrating from the front surface to the back surface of the substrate on at least one side in the lateral direction of the line conductor and the probe. It is possible to create a state as if the width of the board at a certain point had been narrowed. As a result, in the planar line/waveguide converter according to the present invention, even when the circuit section and the probe are formed on the same substrate, the width of the substrate of the circuit section and the width of the substrate of the probe section can be made the same. At the same time, generation of unnecessary propagation modes within the substrate can be suppressed.

In other words, the planar line/waveguide converter according to the present invention maintains a wide frequency band of high-frequency signals that can be propagated from the probe to the waveguide, and also has the same substrate processing as a rectangular MMIC, so that parts can be easily processed. No increase in processing costs or deterioration of reliability.

Moreover, in the planar line/waveguide converter according to the present invention, the waveguide may be a rectangular waveguide.

The present invention provides a planar line/waveguide converter that does not generate unnecessary propagation modes in the substrate while making the substrate width of the circuit section and the substrate width of the probe section the same.

FIG. 1 is an exploded perspective view showing the structure of a planar line/waveguide converter according to a first embodiment of the present invention. FIG. 1 is a perspective view showing the structure of the planar line/waveguide converter after assembly according to the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view after assembly of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. FIG. 2 is a top view showing the structure of the front surface side of the substrate in the planar line/waveguide converter according to the first embodiment of the present invention. (a) is a graph showing the simulation results of the passing loss _S21 of the planar line/waveguide converter when no conductive via hole is formed in the substrate, and (b) is a graph showing the simulation result of the passing loss S21 in the case where the conductive via hole is formed in the substrate. 3 is a graph showing simulation results of the passage loss _S21 of the planar line/waveguide converter in the case of FIG. They are a schematic sectional view of Modification 1 of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. They are a schematic cross-sectional view of Modification 2 of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. They are a schematic sectional view of Modification 3 of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. They are a schematic cross-sectional view of modification 4 of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. They are a schematic sectional view of modification 5 of the planar line/waveguide converter according to the first embodiment of the present invention, and a bottom view showing the configuration on the back side of the substrate. FIG. 3 is a schematic cross-sectional view of a planar line/waveguide converter according to a second embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a planar line/waveguide converter according to another embodiment of the present invention. FIG. 2 is an exploded perspective view showing the configuration of a conventional planar line/waveguide converter for substrates.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a planar line/waveguide converter according to the present invention will be described with reference to the drawings. The planar line/waveguide converter of the present invention is capable of converting a high frequency signal exceeding 100 GHz into a millimeter wave band electromagnetic wave, or conversely, converting a millimeter wave band electromagnetic wave into a high frequency signal. belongs to.

(First embodiment)
First, the configuration of a planar line/waveguide converter according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is an exploded perspective view of the planar line/waveguide converter of this embodiment. FIG. 2 is a perspective view of the planar line/waveguide converter of this embodiment after assembly. FIG. 3 is a schematic cross-sectional view of the planar line/waveguide converter of this embodiment after assembly, and a bottom view of the substrate. FIG. 4 is a top view of the substrate in the planar line/waveguide converter of this embodiment.

As shown in FIGS. 1 to 4, the planar line/waveguide converter 1 includes a substrate 10, a planar line 20, a probe 30, an MMIC 40, and a waveguide 50. The planar line 20, probe 30, and MMIC 40 are formed on one substrate 10. The planar line 20 and MMIC 40 constitute a circuit section.

The planar line 20 includes a substrate 10, a line conductor 11 provided on the front surface of the substrate 10, at least one surface ground conductor 12 provided on the surface of the substrate 10, and a back surface ground conductor provided on the back surface of the substrate 10. 13, and at least one conductive via hole 14 for electrically connecting the front surface ground conductor 12 and the back surface ground conductor 13. Note that hereinafter, the conductive via hole 14 and the through via hole 15 described later will be collectively referred to as simply the via hole 18.

The substrate 10 is, for example, a semiconductor substrate made of GaAs (gallium arsenic), an alumina substrate, a resin substrate, or a quartz glass substrate. The thickness of the substrate 10 is, for example, about 0.05 mm to 0.1 mm.

The conductive via hole 14 is formed by drilling a hole in the substrate 10 with a drill, laser, etc. so as to penetrate from the front surface to the back surface of the substrate 10. The cross-sectional shape of the conductive via hole 14 may be any shape such as a circle, an ellipse, a square, or a rectangle. The conductive via hole 14 has its inner wall surface deposited with a conductive material such as gold or copper, or is embedded with a conductive material so that the surface ground conductor 12 and the back surface ground conductor 13 are electrically connected to each other. There is.

The line conductor 11, the front ground conductor 12, the back ground conductor 13, and the probe 30 are formed by forming a mask pattern on the substrate 10 in which holes for the conductive via holes 14 are formed, and sputtering gold or copper for high frequency signal transmission. It is formed by depositing a thin film of a suitable metal onto the substrate 10. At this time, it is preferable that a metal thin film is simultaneously deposited on the inner wall of the conductive via hole 14. Further, the front surface ground conductor 12 and the back surface ground conductor 13 may be at least a high frequency ground (RF ground), and may be configured to be applied with a bias voltage.

By providing the conductive via hole 14 in the substrate 10, the electromagnetic wave shielding effect of the metal portion of the conductive via hole 14 makes it possible to create a state in which the width of the substrate 10 at the location where the probe 30 is formed appears to be narrowed. .

As shown in FIGS. 1 to 3, the surface ground conductor 12 is provided on the substrate 10, for example, as a land portion of a conductive via hole 14. As shown in FIGS. In this case, the planar line 20 has a microstrip line structure. Alternatively, as shown in FIG. 4, the surface ground conductor 12 may be provided on the substrate 10 as a ground pattern formed on both sides of the line conductor 11 at a predetermined distance. In this case, the planar line 20 has a so-called grounded coplanar line structure. Note that the planar line 20 is not limited to a microstrip line or a grounded coplanar line, and may be a line having another configuration.

The waveguide 50 is a rectangular waveguide with an opening 51 having a rectangular shape and a side opposite to the opening 51 being closed by a reflecting wall 52 . For example, the waveguide 50 may be a WR-8 rectangular waveguide with cross-sectional dimensions of 2.032 mm x 1.016 mm and a pass band of the WR-8 band (90 GHz to 140 GHz).

The substrate 10 is inserted into and attached to a substrate insertion hole 54 provided in a side wall 53 of the waveguide 50. In this state, the waveguide 50 is electrically connected to the back ground conductor 13 via the edge 55 of the board insertion hole 54. The electrical connection between the edge 55 and the back ground conductor 13 can be achieved, for example, by pasting the end of the back ground conductor 13 to the edge 55 with a conductive adhesive. Note that a gap approximately equal to the thickness of the substrate 10 is provided between the substrate insertion hole 54 and the surface of the substrate 10 so that the line conductor 11 and the probe 30 are not electrically connected to the waveguide 50. There is. For example, the substrate insertion hole 54 is formed at a height near the center of the side wall 53 of the waveguide 50.

The MMIC 40 is an integrated circuit including semiconductor components such as field effect transistors (FETs), and functions as, for example, an amplifier or a frequency converter. The width of the MMIC 40 is, for example, about 1 mm to 1.5 mm.

For example, as shown in FIG. 3, the MMIC 40 includes a signal electrode 41 provided on the front side of the substrate 10 and electrically connected to the line conductor 11, and a ground electrode 42 electrically connected to the back ground conductor 13. and has. The signal electrode 41 of the MMIC 40 is electrically connected to the line conductor 11 by, for example, a bonding wire. Further, the ground electrode 42 of the MMIC 40 is electrically connected to the front ground conductor 12 and the back ground conductor 13 by interlayer connection via bonding wires, via holes, etc., for example.

The probe 30 is a strip conductor provided on the surface of the substrate 10, integrally formed with the line conductor 11, and extending into the inside of the waveguide 50. The probe 30 functions as an antenna that excites the waveguide 50. Therefore, as shown in the lower part of FIG. 3, the back surface ground conductor 13 is not provided in the region of the back surface of the substrate 10 including directly below the probes 30.

As shown in FIGS. 2 and 3, with the substrate 10 attached to the substrate insertion hole 54 of the waveguide 50, the probe 30 is inside the waveguide 50, and the planar line 20 is attached to the edge 55 of the substrate insertion hole 54. The MMIC 40 is arranged above and outside the waveguide 50 .

The length L of the probe 30 is approximately 1/4 of the wavelength λs on the substrate 10 in the frequency band used in the planar line/waveguide converter 1. Here, the wavelength on the substrate 10 means an effective wavelength that takes into account the wavelength shortening effect due to the dielectric properties of the substrate 10. Note that it is desirable that the distance from the tip of the probe 30 to the end of the substrate 10 be as small as possible. Further, it is desirable that the width of the probe 30 is such that impedance matching can be achieved with the planar line 20.

Further, the distance BS (back short length) from the center position of the probe 30 in the width direction to the reflecting wall 52 of the waveguide 50 is the effective guide wavelength λg taking into account the wavelength shortening effect due to the dielectric property of the substrate 10. It is sufficient if it is about 1/4 of that.

With the above configuration, the high frequency signal transmitted from the MMIC 40 is transmitted through the planar line 20, radiated from the probe 30 within the waveguide 50, and propagated within the waveguide 50. Conversely, the electromagnetic wave input into the opening 51 of the waveguide 50 propagates through the waveguide 50, is received by the probe 30, is transmitted through the planar line 20, and is received by the MMIC 40.

FIG. 5A is a graph showing a simulation result of the passage loss _S21 of a planar line/waveguide converter in which the conductive via hole 14 is not formed in the substrate 10 (no conductive via hole). On the other hand, FIG. 5(b) is a graph showing the simulation results of the passing loss _S21 of the planar line/waveguide converter 1 of this embodiment in which the conductive via hole 14 is formed in the substrate 10 (with the conductive via hole). It is.

The simulation conditions are as follows.
- Substrate dielectric constant: 8.5
・Size of board: width 1mm, length 0.835mm, thickness 0.1mm
・Width of line conductor and probe: 0.06mm
・Metal type of line conductor and probe: Gold ・Thickness of line conductor and probe: 0.003mm
・Number of conductive via holes: 2 (if there is a conductive via hole)
・Via hole diameter: 0.1mm (with conductive via hole)
・Center position of conductive via hole: 0.15 mm inside from the edge of the board in both the width and length directions (if there is a conductive via hole)
・Distance from the center position of the conductive via hole to the line conductor: 0.35mm (if there is a conductive via hole)

As shown in FIG. 5(a), in the configuration without conductive via holes, the transmission loss _S21 was 1 dB or less up to 115 GHz. On the other hand, as shown in FIG. 5(b), in the configuration with conductive via holes in this embodiment, the transmission loss _S21 can be as low as 1 dB or less up to 135 GHz. This is considered to be because the provision of the conductive via hole 14 in the substrate 10 made it possible to prevent unnecessary propagation modes from occurring within the substrate 10.

Although FIG. 3 shows a configuration example in which one conductive via hole 14 is arranged on each side of the line conductor 11 in the horizontal direction, as shown in FIG. By arranging two of them, unnecessary propagation modes may be prevented from occurring within the substrate 10.

Further, as shown in FIG. 7, in the planar line/waveguide converter 1 of this embodiment, at least one through via hole 15 that is not connected to the front surface ground conductor 12 and the back surface ground conductor 13 is located on the surface of the substrate 10. It may be configured to penetrate from the top to the back surface. The through via hole 15 is provided in an area including at least one back conductor 16 provided in an area on the back surface of the substrate 10 where the back surface ground conductor 13 is not formed, and a region directly above the back surface conductor 16 on the front surface of the substrate 10. At least one surface conductor 17 is electrically connected.

The through via hole 15 can be formed in the same manner as the conductive via hole 14 described above. By providing the through-via hole 15 in the substrate 10, it is possible to create a state in which the width of the substrate 10 at the location where the probe 30 is formed appears to be narrowed due to the electromagnetic wave shielding effect of the metal part of the through-via hole 15. .

Furthermore, as shown in FIG. 8, by arranging the through via hole 15 on the reflecting wall 52 side on one side of the probe 30 in the lateral direction, the radiation pattern of the probe 30 is spread toward the opening 51 of the waveguide 50. The loss when exciting the waveguide 50 can be reduced by changing the waveguide. Furthermore, by arranging the through via hole 15 on the side of the reflecting wall 52 on one side of the probe 30 in the lateral direction, even if the distance between the opening 51 of the waveguide 50 and the reflecting wall 52 deviates due to assembly, the sensitivity of the probe 30 remains unchanged. The impact of this can be reduced.

Further, as shown in FIG. 9, at least one surface ground conductor 12 and at least one surface conductor 17 may be integrated on one side or both sides of the probe 30 in the lateral direction. Furthermore, at least one back ground conductor 13 and at least one back conductor 16 may be integrated. With such a configuration, it is possible to prevent electromagnetic waves from passing between the via holes 18 and direct the radiation direction of the electromagnetic waves from the probe 30 in a desired direction.

Further, as shown in FIG. 10, the conductive via hole 14 and the through via hole 15 that are electrically connected to each other and the through via hole 15 that is not electrically connected to the conductive via hole 14 may coexist.

The interval between adjacent via holes 18 is set to, for example, about twice the diameter of the via holes 18 due to manufacturing limitations such as the accuracy of hole processing and the strength of the substrate 10. Further, the distance between the via hole 18 and the line conductor 11 or the probe 30 may be set to, for example, about twice the diameter of the via hole 18. Further, the diameter of the via hole 18 may be set to be the same as the thickness of the substrate 10, for example. Note that the number of via holes 18 is arbitrary.

As explained above, in the planar line/waveguide converter 1 according to the present embodiment, the conductive via hole 14 penetrating from the front surface to the back surface of the substrate 10 is arranged on at least one side in the lateral direction of the line conductor 11. It is possible to create a state as if the width of the substrate 10 at the location where the probe 30 is formed is narrowed. As a result, in the planar line/waveguide converter 1, even when the circuit section and the probe 30 are formed on the same substrate 10, the width of the substrate 10 of the circuit section and the width of the substrate 10 of the probe section are the same. At the same time, it is possible to suppress the generation of unnecessary propagation modes within the substrate 10.

That is, the planar line/waveguide converter 1 according to the present embodiment maintains a wide frequency band of high-frequency signals that can be propagated from the probe 30 to the waveguide 50, and uses the same substrate processing as the rectangular MMIC 40. This prevents increases in parts processing costs and reliability deterioration.

Further, in the planar line/waveguide converter 1 according to the present embodiment, the probe 30 is formed by disposing the through via hole 15 that penetrates from the front surface to the back surface of the substrate 10 on at least one side of the probe 30 in the lateral direction. It is possible to create a state as if the width of the substrate 10 at the location where the width was narrowed. Thereby, the planar line/waveguide converter 1 can change the radiation pattern of the probe 30 into a desired shape.

Further, in the planar line/waveguide converter 1 according to the present embodiment, at least one front surface ground conductor 12 and at least one front surface conductor 17 are integrated, and a back surface ground conductor 13 and at least one back surface conductor 16 are integrated. By being integrated, it is possible to prevent electromagnetic waves from passing between the via holes 18 and direct the radiation direction of electromagnetic waves from the probe 30 in a desired direction.

(Second embodiment)
Next, a planar line/waveguide converter 2 according to a second embodiment of the present invention will be described with reference to the drawings. Note that descriptions of configurations and operations similar to those of the first embodiment will be omitted as appropriate.

The planar line/waveguide converter 1 of the first embodiment had a configuration in which a via hole 18 was provided in the substrate 10, but the planar line/waveguide converter 2 of this embodiment has a via hole instead of a via hole. , a through hole 19 penetrating from the front surface to the back surface of the substrate 10 is provided.

Note that the configurations of the substrate 10, line conductor 11, front surface ground conductor 12, back surface ground conductor 13, probe 30, MMIC 40, and waveguide 50 are the same as those of the first embodiment.

As shown in FIG. 11, the through holes 19 are formed, for example, on both sides or one side of the line conductor 11 and the probe 30 in the lateral direction. The through hole 19 is formed by drilling a hole through the substrate 10 using a drill, laser, or the like. The cross-sectional shape of the through hole 19 may be any shape such as a circle, an ellipse, a square, or a rectangle. Unlike the via hole 18 in the first embodiment, the through hole 19 does not have electrical conductivity.

By providing the through hole 19 in the substrate 10, an air _layer having a dielectric constant ε _{r lower than the dielectric constant ε r} (for example, about 10) of the substrate 10 (ε _{r is} approximately 1) is formed in the line conductor 11 in the substrate 10 . and are formed in the lateral direction of the probe 30. By providing a difference in dielectric constant within the substrate 10 in this way, it becomes difficult for electromagnetic waves to spread in the lateral direction of the probe 30, and the width of the substrate 10 where the probe 30 is formed is made narrower. can create a state. This makes it possible to suppress the spread of electromagnetic waves in unnecessary directions due to unnecessary propagation modes.

The diameter of the through hole 19 can be set to be the same as the thickness of the substrate 10, for example. The interval between adjacent through holes 19 is preferably 1/4 or less of the wavelength λs on the substrate 10 in the frequency band used in the planar line/waveguide converter 2, and may be, for example, 1/8. Alternatively, the interval between adjacent through holes 19 may be, for example, approximately twice the diameter of the through holes 19 due to manufacturing limitations such as the accuracy of hole processing and the strength of the substrate 10. Further, the distance between the through hole 19 and the line conductor 11 or the probe 30 may be set to, for example, about twice the diameter of the through hole 19.

Although FIG. 11 shows an example in which two rows of through holes 19 are arranged on both sides of the line conductor 11 and the probe 30 in the lateral direction, by making the distance between the line conductor 11 and the probe 30 and the through holes 19 close, A configuration may be adopted in which three or more rows of through holes 19 are arranged on both sides of the line conductor 11 and the probe 30 in the lateral direction.

In addition, in the above description, the size of the through hole 19 is the same as the thickness of the substrate 10, but by making the size of the through hole 19 larger than the thickness of the substrate 10, a dielectric constant is created in the substrate 10. The low area may be provided wider to further prevent unnecessary spread of propagation modes.

As described above, in the planar line/waveguide converter 2 according to the present embodiment, the through hole 19 penetrating from the front surface to the back surface of the substrate 10 is arranged at least on one side in the lateral direction of the line conductor 11 and the probe 30. By doing so, it is possible to create a state as if the width of the substrate 10 at the location where the probe 30 is formed is narrowed. As a result, in the planar line/waveguide converter 2, even when the circuit section and the probe 30 are formed on the same substrate 10, the width of the substrate 10 of the circuit section and the width of the substrate 10 of the probe section are the same. At the same time, it is possible to suppress the generation of unnecessary propagation modes within the substrate 10.

That is, the planar line/waveguide converter 2 according to this embodiment maintains a wide frequency band of high-frequency signals that can be propagated from the probe 30 to the waveguide 50, and uses the same substrate processing as the rectangular MMIC 40. This prevents increases in parts processing costs and reliability deterioration.

(Other embodiments)
In the description of the first embodiment and the second embodiment, it is assumed that the MMIC 40, the planar line 20, and the probe 30 are formed on one substrate 10, but as shown in FIG. The tube converters 1 and 2 may have a structure in which a MMIC 40 chip is later mounted on a substrate 10 on which a planar line 20 and a probe 30 are formed.

1, 2 Planar line/waveguide converter 10 Substrate 11 Line conductor 12 Surface ground conductor 13 Back ground conductor 14 Conductive via hole 15 Through via hole 16 Back conductor 17 Surface conductor 18 Via hole 19 Through hole 20 Planar line 30 Probe 40 MMIC
41 Signal electrode 42 Ground electrode 50 Waveguide 51 Opening 52 Reflection wall 53 Side wall 54 Board insertion hole 55 Edge

Claims (5)

a substrate (10);
a line conductor (11) provided on the surface of the substrate;
at least one surface ground conductor (12) provided on the surface of the substrate;
a back surface ground conductor (13) provided on the back surface of the substrate;
at least one conductive via hole (14) penetrating the substrate from the front surface to the back surface and electrically connecting the front surface ground conductor and the back surface ground conductor;
a waveguide (50) in which the substrate is inserted into a substrate insertion hole (54) provided in a side wall (53), and an edge (55) of the substrate insertion hole is electrically connected to the back ground conductor; ,
a probe (30) provided on the surface of the substrate, integrally formed with the line conductor, and extending into the inside of the waveguide;
an MMIC (40) provided on the front side of the substrate and having a signal electrode (41) electrically connected to the line conductor and a ground electrode (42) electrically connected to the back surface ground conductor; , comprising;
The back surface ground conductor is not provided in a region including directly below the probe on the back surface of the substrate,
A planar line/waveguide converter, wherein the conductive via hole is disposed on at least one side of the line conductor in the lateral direction. at least one back conductor (16) provided on the back surface of the substrate;
at least one surface conductor (17) provided in a region including directly above the back conductor on the front surface of the substrate;
further comprising at least one through via hole (15) penetrating from the front surface to the back surface of the substrate and electrically connecting the front surface conductor and the back surface conductor,
The planar line/waveguide converter according to claim 1, wherein the through via hole is arranged on at least one side of the probe in the lateral direction. 3. The at least one surface ground conductor and at least one surface conductor are integrated, and the back surface ground conductor and at least one back surface conductor are integrated. Planar line/waveguide converter. a substrate (10);
a line conductor (11) provided on the surface of the substrate;
at least one surface ground conductor (12) provided on the surface of the substrate;
a back surface ground conductor (13) provided on the back surface of the substrate;
a through hole (19) penetrating from the front surface to the back surface of the substrate;
a waveguide (50) in which the substrate is inserted into a substrate insertion hole (54) provided in a side wall (53), and an edge (55) of the substrate insertion hole is electrically connected to the back ground conductor; ,
a probe (30) provided on the surface of the substrate, integrally formed with the line conductor, and extending into the inside of the waveguide;
an MMIC (40) provided on the front side of the substrate and having a signal electrode (41) electrically connected to the line conductor and a ground electrode (42) electrically connected to the back surface ground conductor; , comprising;
The back surface ground conductor is not provided in a region including directly below the probe on the back surface of the substrate,
A planar line/waveguide converter, wherein the through hole is arranged on at least one side of the line conductor and the probe in the lateral direction. 5. The planar line/waveguide converter according to claim 4, wherein the waveguide is a rectangular waveguide.

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