JP4982237B2 - High frequency circuit - Google Patents

Description

  The present invention relates to a high-frequency circuit, and more particularly, to a high-frequency circuit incorporated in a transceiver used for radar, wireless communication, satellite communication, or the like using a high-frequency wave such as a microwave band or a millimeter wave band as a carrier wave.

  2. Description of the Related Art Conventionally, as a method for attaching a semiconductor element to a wiring board while increasing the density of the semiconductor element, a high-frequency circuit in which the semiconductor element is attached to the wiring board on which a microstrip line is formed is known.

  For example, as shown in FIG. 5, a semiconductor element 2 such as an amplifying element is mounted on the surface of a substrate 1 made of a dielectric having a microstrip line formed on the front surface and a ground pattern formed on the back surface.

  The substrate 1 is mounted on a metal case 3 such as an aluminum die-cast so that the ground pattern is on the lower surface. The volume of the case 3 surrounding the substrate 1, that is, the substrate 1 and the case 3 It is known that the frequency characteristic is determined by the volume of the space 4 formed on the inner peripheral surface.

  However, when the substrate 1 on which such a microstrip line is formed is attached to the case 3, it is necessary to form the space 4. Therefore, in the microwave band having a short wavelength of 10 GHz or more, radiation noise is generated in the space 4. May occur, or may be caused by transmission of radio waves between the input and output of the semiconductor element 2, deterioration of frequency characteristics, deterioration of voltage standing wave ratio (VSWR) of input and output of the high frequency circuit, and the like.

  For this reason, in order to eliminate such problems in the production line, adjustment work such as the width and length of the high-frequency signal line is required for each high-frequency circuit, and the productivity of the high-frequency circuit has deteriorated. .

  In order to solve such a problem, a high-frequency circuit having a triplate structure that can eliminate the extra space 4 is known and is shown in FIG. 6 (see, for example, Patent Document 1).

  As shown in FIG. 6, a multilayer substrate 11 is housed in a bottomed case 10 made of aluminum die cast or the like. The multilayer substrate 11 includes a dielectric 12, ground conductor layers 13 and 14 provided on the upper and lower surfaces of the dielectric 12, a recess 16 that penetrates the ground conductor layer 13 and exposes the high-frequency signal line 15, and a recess 16 And a semiconductor element 17 housed in the housing.

  The multilayer substrate 11 is attached to the case 10 so that the lower ground conductor layer 14 contacts the bottom surface of the case 10, and a metal lid 18 is attached to the case 10 so as to contact the upper ground conductor layer 13. It is done.

  The lid 18 has a screw hole 18a, the multilayer substrate 11 has a screw hole 11a, and the case 10 has a screw groove 10a into which a screw is screwed.

Then, the screw 19 is inserted through the screw holes 18 a and 11 a, and the screw 19 is screwed into the screw hole 10 a of the case 10, whereby the multilayer substrate 11 and the semiconductor element 17 are attached to the case 10.
JP 2000-269382 A

  However, in such a conventional high-frequency circuit, the screw 19 is inserted through the screw holes 18 a and 11 a and the screw 19 is screwed into the screw hole 10 a of the case 10, whereby the multilayer substrate 11 and the semiconductor element 17. Is attached to the case 10, no gap is formed between the lid 18 around the screw 19, the multilayer substrate 11, and the case 10, but the lid 18 separated from the screw 19 and the multilayer substrate 11. A gap may be formed between the cases 10.

  Thus, when gaps are formed between the lid 18 and the multilayer substrate 11 and between the multilayer substrate 11 and the case 10, a potential difference is generated in a high frequency between the lid 18 and the multilayer substrate 11 and between the multilayer substrate 11 and the case 10. May occur and the high-frequency characteristics of the high-frequency circuit may become unstable.

  For this reason, for example, when a signal is input to the high-frequency circuit from a predetermined input circuit connected to the high-frequency circuit, there is a possibility that variations in signals transmitted from the high-frequency circuit to the predetermined output circuit may occur.

  In addition to forming a gap between the lid 18 and the multilayer substrate 11, a gap is also formed between the lid 18 and the semiconductor element 17. In this respect, the high frequency characteristics may become unstable, and there is still room for improvement.

  The present invention has been made to solve the conventional problems, and provides a high-frequency circuit that can maintain a high-frequency characteristic between a housing and a multilayer substrate at a high frequency and can stabilize high-frequency characteristics. With the goal.

  A high-frequency circuit according to the present invention includes a bottomed case having one end opened, a casing having a closing member attached to the case so as to close the opening, and a dielectric sandwiched between upper and lower ground conductor layers A multilayer substrate housed in the case having a high-frequency signal line formed by a strip line and having one ground conductor layer in contact with the case; and a fixing means for fixing the blocking member to the case In the high-frequency circuit, a metal elastic sheet is interposed between the multilayer substrate and the closing member so as to be in contact with the other ground conductor layer, and the blocking member attaches the multilayer substrate via the elastic sheet. It is comprised from what presses toward the bottom face of a case.

With this configuration, a metal elastic sheet is interposed between the multilayer substrate and the closing member, and the closing member presses the multilayer substrate toward the bottom surface of the case via the elastic sheet. No gap is formed between the ground conductor layer provided on the case and the case, and no gap is formed between the ground conductor layer provided on the upper portion of the multilayer substrate and the closing member. That is, the housing and the ground conductor layer are not in close contact with each other, and a gap is not formed between the housing and the ground conductor layer.
Therefore, the casing and the multilayer substrate can be kept at the same potential in terms of high frequency, and the high frequency characteristics can be stabilized. For this reason, when a high-frequency circuit is connected to a predetermined input circuit or a predetermined output circuit, when a signal is input from the input circuit to the high-frequency circuit, variations in signals transmitted from the high-frequency circuit to the output circuit occur. Can be prevented.

  In the high-frequency circuit according to the present invention, the multilayer substrate has a recess that penetrates through the other ground conductor layer and a part of the dielectric, and the high-frequency signal line is exposed on a bottom surface of the recess, and the high-frequency circuit The semiconductor element is accommodated in the recess so as to be connected to the signal line, and the elastic sheet is configured to have a contact portion that contacts the upper surface of the semiconductor element.

  With this configuration, no gap is formed between the semiconductor element and the closing member, and no gap is formed between the ground conductor layer provided on the upper portion of the multilayer substrate and the closing member. The element and the blocking member and the multilayer substrate and the blocking member can be kept at the same potential in terms of high frequency, and the high frequency characteristics can be stabilized.

  In addition, since the elastic sheet is provided with a contact portion that contacts the upper surface of the semiconductor element, even if the upper surface of the semiconductor element protrudes from the ground conductor layer on the upper side of the multilayer substrate, the elastic sheet is securely adhered to the semiconductor element. It is possible to reliably prevent a gap from being formed between the semiconductor element and the closing member.

  In the high-frequency circuit according to the present invention, an area of the elastic sheet is formed larger than an opening area of the case, and a bent portion is provided on an outer peripheral portion of the elastic sheet. It is comprised from what contacts the inner peripheral part.

  With this configuration, when a gap is formed between both end portions of the multilayer substrate and the inner peripheral surface of the case due to processing accuracy or the like, the bent portion is pressed by the closing member and bent to the inner peripheral surface of the case. In this state, the gap formed between both end portions of the multilayer substrate and the inner peripheral surface of the case can be filled, and the upper ground conductor layer can be reliably brought into contact with the case and the closing member.

  For this reason, the same potential can be maintained between the housing and the multilayer substrate at a higher frequency, and the high frequency characteristics can be further stabilized. Further, it is possible to suppress radiation noise from being generated from the multilayer substrate in the gap between the both end portions of the closing member and the semiconductor element and the inner peripheral surface of the case.

  The present invention can provide a high-frequency circuit that can maintain the same potential in high frequency between the casing and the multilayer substrate and can stabilize high-frequency characteristics.

Hereinafter, embodiments of a high-frequency circuit according to the present invention will be described with reference to the drawings.
1 to 4 are diagrams showing an embodiment of a high-frequency circuit according to the present invention.
First, the configuration will be described.

  As shown in FIG. 1, the solid-state power amplifier 21 is, for example, a solid-state power amplifier that amplifies a microwave used in an ODU (Out door unit) of a very small earth station (VSAT) that performs satellite communication. (Solid state power amplifier: SSPA).

  The solid-state power amplifier 21 includes a bottomed case 22 in which an opening 22a having one end opened, and a lid 23 as a closing member attached to the case 22 so as to close the opening 22a. The case 22 and the lid 23 constitute a housing 24. The case 22 and the lid 23 are made of a metal such as an aluminum alloy, a zinc alloy, or a magnesium alloy.

  A multilayer substrate 25 having a triplate structure is accommodated in the case 22, and the multilayer substrate 25 is formed between a pair of insulating layers 26 and 27 as dielectrics and the insulating layers 26 and 27. A copper foil high-frequency signal line 28 composed of strip lines, a ground conductor layer 29 such as a copper foil formed on the entire lower surface of the insulating layer 26, and a ground conductor such as a copper foil formed on the entire upper surface of the insulating layer 27. Layer 30.

  That is, the multilayer substrate 25 has a high-frequency signal line 28 formed of a strip line on the insulating layers 26 and 27 sandwiched between the ground conductor layers 29 and 30, and the lower ground conductor layer 29 is in contact with the case 22. 22.

  In addition, the multilayer substrate 25 has a recess 31, which penetrates the ground conductor layer 30 and the insulating layer 27, and the high-frequency signal line 28 is exposed on the bottom surface of the recess 31.

  An amplifying element 32 as a semiconductor element is accommodated in the recess 31. The amplifying element 32 is connected to the high-frequency signal line 28 via a pump (not shown).

  Further, a spring sheet 33 as a rectangular elastic sheet made of a copper alloy such as phosphor bronze is interposed between the multilayer substrate 25 and the lid 23, and the area of the spring sheet 33 is larger than the opening area of the opening 22a. Largely formed. The inner peripheral wall of the case 22 is formed in a rectangular shape so that the opening 22a of the case 22 also has a rectangular shape.

  As shown in FIG. 2, a bent portion 33 a is formed on the outer peripheral surface of the spring sheet 33, and the bent portion 33 a bends and contacts the inner peripheral surface of the case 22 when the spring sheet 33 is stored in the case 22. It is supposed to be.

  A pair of tongue portions 33c and 33d as contact portions are formed on the inner peripheral portion of the spring seat 33 via a notch portion 33b, and the tongue portions 33c and 33d protrude upward from the ground conductor layer 30. It is in contact with the upper surface of the amplifying element 32. At this time, the tongue portions 33c and 33d protrude upward from the surface of the spring seat 33 (see FIG. 4).

  The lid 23 is formed with a screw hole 23 a and the spring seat 33 is formed with a screw hole 33 e. Further, screw holes 25 a pass through the multilayer substrate 25, and screw grooves 22 b are formed on the bottom surface of the case 22.

  A plurality of screws 34 (six in this embodiment) constituting the fixing means are inserted into the screw holes 23a, 33e, and 25a, and these screws 34 are screw grooves of the case 22. 22b is screwed.

  Therefore, the multilayer substrate 25 is fixed to the case 22 by the screws 34. At this time, the lid 23 presses the multilayer substrate 25 toward the bottom surface of the case 22 via the spring sheet 33 by the fastening force of the screws 34.

  In the present embodiment, in order to attach the multilayer substrate 25 to the housing 24, the multilayer substrate 25 is accommodated in the case 22 with the ground conductor layer 29 facing downward, and then the spring sheet 33 is placed on the ground conductor layer 30 side.

  Since the spring sheet 33 is formed larger than the opening area of the opening 22 a of the case 22, the bent portion 33 a is slidably contacted with the inner peripheral surface of the case 22 when being accommodated in the case 22. Placed. Further, when the spring sheet 33 is placed on the multilayer substrate 25, the tongue portions 33 c and 33 d are positioned on the amplification element 32.

  Next, after attaching the lid 23 to the case 22 so as to close the opening 22a, the screw 34 is inserted into the screw hole 23a, the screw hole 33e, and the screw hole 25a, and the screw 34 is screwed into the screw groove 22b of the case 22. By doing so, the multilayer substrate 25 is fixed to the case 22.

  At this time, the lid 23 presses the multilayer substrate 25 toward the bottom surface of the case 22 via the spring sheet 33 by the fastening force of the screw 34, so that the ground conductor layer 29 of the multilayer substrate 25 and the bottom surface of the case 22 are in close contact with each other. Since the ground conductor layer 30 is in close contact with the lid 23 via the spring sheet 33, no gap is generated between the ground conductor layer 29 and the case 22 and between the ground conductor layer 30 and the spring sheet 33.

  Further, when the lid 23 presses the multilayer substrate 25 via the spring sheet 33, the tongue portions 33c and 33d bend upward and come into close contact with the upper surface of the amplifying element 32 protruding from the ground conductor layer 30 as shown in FIG. Therefore, there is no gap between the amplifying element 32 and the lid 23 via the spring sheet 33.

  Further, when a gap is formed between both end portions of the multilayer substrate 25 and the inner peripheral surface of the case 22 due to processing accuracy or the like, the bent portion 33 a is pressed by the lid 23 and bent to the inner peripheral surface of the case 22. The ground conductor layer 30 can be brought into contact with the case 22 and the lid 23 by filling the gap between the both ends of the multilayer substrate 25 and the inner peripheral surface of the case 22 (FIG. 3). reference).

As described above, in the present embodiment, the spring sheet 33 made of phosphor bronze is interposed between the multilayer substrate and the lid 23, and the lid 23 moves the multilayer substrate 25 toward the bottom surface of the case 22 via the spring sheet 33. Since the pressing is performed, no gap is formed between the ground conductor layer 29 provided at the lower portion of the multilayer substrate 25 and the bottom surface of the case 22, and the ground conductor layer provided at the upper portion of the multilayer substrate 25. No gap is formed between 30 and the lid 23. That is, the housing 24 and the ground conductor layers 29 and 30 are not in close contact with each other, and a gap is not formed between the housing 24 and the ground conductor layers 29 and 30. For this reason, the housing 24 and the multilayer substrate 25 can be kept at the same potential in terms of high frequency, and high frequency characteristics can be stabilized.
For this reason, when a signal is input to the solid-state power amplifier 21 from a frequency conversion circuit or the like provided in the ODU, it is possible to prevent the variation of the signal and transmit the signal to a predetermined output circuit.

  The multilayer substrate 25 of the present embodiment has a recess 31 that penetrates the upper ground conductor layer 30 and the insulating layer 27, exposes the high-frequency signal line 28 to the bottom surface of the recess 31, and The amplifying element 32 is accommodated in the recess 31 so as to be connected, and the spring sheet 33 has tongues 33 c and 33 d that contact the upper surface of the amplifying element 32.

  For this reason, a gap is not formed between the amplifying element 32 and the lid 23, and a gap is prevented from being formed between the ground conductor layer 30 provided on the multilayer substrate 25 and the lid 23. be able to. Therefore, the amplifying element 32 and the lid 23 and the multilayer substrate 25 and the lid 23 can be kept at the same potential in terms of high frequency, and the high frequency characteristics can be stabilized.

  In the present embodiment, since the tongue 33c, 33d that contacts the upper surface of the amplifying element 32 is provided on the spring sheet 33, the upper surface of the amplifying element 32 protrudes from the ground conductor layer 30 above the multilayer substrate 25. Even if it is a structure, the spring sheet 33 can be made to contact | adhere reliably to the amplification element 32, and it can prevent reliably that a clearance gap is formed between the amplification element 32 and the lid | cover 23. FIG.

  Further, in the present embodiment, the area of the spring sheet 33 is formed larger than the opening area of the opening 22 a of the case 22, the bent portion 33 a is provided on the outer peripheral portion of the spring sheet 33, and the bent portion 33 a is the inner periphery of the case 22. It was made to contact a part.

  For this reason, when a gap is formed between both end portions of the multilayer substrate 25 and the inner peripheral surface of the case 22 due to processing accuracy or the like, the bent portion 33a is pressed by the lid 23 and bent to the inner peripheral surface of the case. In contact with each other, filling a gap formed between both end portions of the multilayer substrate 25 and the inner peripheral surface of the case 22 so that the upper grounding conductor layer 30 can be reliably brought into contact with the case and the lid 23. .

  Therefore, the same potential can be maintained between the housing 24 and the multilayer substrate 25 at a higher frequency, and the high frequency characteristics can be further stabilized. Further, it is possible to suppress radiation noise from being generated from the multilayer substrate 25 in the gap between the both ends of the lid 23 and the amplifying element 32 and the inner peripheral surface of the case 22.

  In this embodiment, the semiconductor element is applied to the amplifying element 32 of the solid-state power amplifier 21 provided in the ODU. However, the semiconductor element is not limited to the ODU, and a semiconductor element such as a Pin diode may be used as a semiconductor element. Needless to say, the present invention can be applied to diodes, isolators, and the like. In short, the present invention can be applied to any circuit as long as it is a high-frequency circuit using a multi-layer substrate having a triplate structure.

  Further, the multilayer substrate 25 may be used as a filter circuit or a hybrid circuit by using a stripline pattern of the multilayer substrate 25 having a triplate structure without using a semiconductor element such as the amplifying element 32.

  In the present embodiment, since the multilayer substrate 25 having the triplate structure is used for the high-frequency circuit, radiation noise is generated, transmission due to wraparound of radio waves between the input and output of the amplifying element 32, and deterioration of frequency characteristics. In addition to being able to suppress the deterioration of the voltage standing wave ratio (VSWR) of the input / output of the solid-state power amplifier 21, the adjustment work such as the microstrip line is unnecessary and the productivity of the high-frequency circuit is deteriorated. Needless to say, it can be prevented.

  In addition, the embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the high-frequency circuit according to the present invention has the effect that the casing and the multilayer substrate can be maintained at the same potential in terms of high frequency, and the high-frequency characteristics can be stabilized. It is useful as a high-frequency circuit or the like built in a transmitter / receiver used for radar, radio communication, satellite communication or the like using a high-frequency wave such as a millimeter wave band as a carrier wave.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the high frequency circuit which concerns on this invention, and is sectional drawing of a high frequency circuit. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the high frequency circuit which concerns on this invention, (a) is a top view of an elastic sheet, (b) Longitudinal side view of an elastic sheet, (c) Short side view of an elastic sheet is there. It is a figure which shows one Embodiment of the high frequency circuit which concerns on this invention, and is principal part sectional drawing of the high frequency circuit for demonstrating the bending part of an elastic sheet. It is a figure which shows one Embodiment of the high frequency circuit which concerns on this invention, and is principal part sectional drawing of the high frequency circuit for demonstrating the tongue part of an elastic sheet. It is sectional drawing of the high frequency circuit using the conventional microstrip line. It is sectional drawing of the high frequency circuit using the stripline of the conventional triplate structure.

Explanation of symbols

21 Solid-state power amplifier (high frequency circuit)
22 Case
22a Opening 23 Lid (closing member, casing)
24 Housing 25 Multi-layer substrate 26, 27 Insulating layer 28 High-frequency signal line 29, 30 Ground conductor layer (dielectric)
31 Recess 32 Amplifying element (semiconductor element)
33 Spring sheet (elastic sheet)
33a Bending part 33c, 33d Tongue part (contact part)
34 Screw (fixing means)

Claims (2)

A case having a bottomed case having one end opened, a housing having a closing member attached to the case so as to close the opening, and a high-frequency signal line using a strip line in a dielectric sandwiched between upper and lower ground conductor layers In a high-frequency circuit comprising a multilayer substrate housed in the case so that one ground conductor layer is in contact with the case, and a fixing means for fixing the closing member to the case,
A metal elastic sheet is interposed between the multilayer substrate and the closing member so as to be in contact with the other grounding conductor layer, and the blocking member faces the multilayer substrate toward the bottom surface of the case via the elastic sheet. pressing Te,
The multilayer substrate has a concave portion penetrating the other ground conductor layer and a part of the dielectric, and exposes the high-frequency signal line to a bottom surface of the concave portion, and the concave portion is connected to the high-frequency signal line. Contains semiconductor elements,
The high-frequency circuit according to claim 1, wherein the elastic sheet has a contact portion that contacts an upper surface of the semiconductor element . An area of the elastic sheet is formed larger than an opening area of the case, and a bent portion is provided on an outer peripheral portion of the elastic sheet, and the bent portion is in contact with an inner peripheral portion of the case. The high-frequency circuit according to claim 1.

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