JP2007300153A - Microwave circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave circuit device wherein impedance mismatch is hardly caused and the number of screws in use can be reduced in addition. <P>SOLUTION: The microwave circuit device is configured such that a metallic part of a metallic plate adhered with a dielectric body comes into contact with a ground terminal of a lower face of a microwave component so as to reduce the distance of a current path for ground connection so that the impedance mismatch hardly takes place. In addition, the metallic plate is designed to be extended up to the lower face of the microwave component so as to decrease the number of the screws in use. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microwave circuit device in which a microwave component incorporating a microwave circuit and a metal plate to which a dielectric substrate is attached are placed.

  A microwave circuit device is usually configured by placing a microwave component containing a microwave circuit and a dielectric substrate in a case.

  As shown in FIG. 3, the case 305 on which the microwave component 301, the dielectric substrate 302, and the metal plate 304 are placed conventionally has a base portion 307 on which the portion on which the microwave component 301 is placed protrudes. Further, the dielectric substrate 302 is fixed on the metal plate 304 by a screw 303b at a position close to the microwave component 301 in addition to the screw 303a. In addition, there was a gap between the microwave component 301 and the metal plate 304.

  5 is a cross-sectional view taken along line BB in FIG. Assuming that the signal line connection current flows in the direction of the arrow 506, the ground connection current flows so as to bypass the gap between the microwave component 501 and the metal plate 304 as indicated by the arrow 507. For this reason, in the microwave circuit device, there is a difference between the distance of the current path of the signal line connection and the distance of the current path of the grant connection, and this difference causes an impedance mismatch.

  FIG. 6 is an enlarged view of a portion C in FIG. As shown in FIG. 6, when the screw 303 b is stopped at a position away from the end of the metal plate 605, a gap is generated between the metal plate 605 and the case 602, and the ground connection current is increased as indicated by an arrow 606. Diverted and the impedance matching worsened. Due to this impedance mismatch, a reflected wave is generated, which causes a deterioration in the voltage standing wave ratio (VSWR: Voltage Standing Wave Ratio).

Patent Document 1 exists as a document indicating such a conventional technique. As shown in FIG. 5 of Patent Document 1, the current in the ground connection follows the path of the terminal board 2 -the metal base 1 -the microwave component, and the distance of the current path becomes longer than the current path of the signal line connection. End up.
JP-A-4-346501, FIG.

  The present invention has been made in view of the above-described problems of the conventional microwave circuit device, and an object thereof is to provide a microwave circuit device with improved impedance matching and voltage standing wave ratio.

  The present invention aims to improve impedance matching and voltage standing wave ratio by shortening the distance of the current path of ground connection.

  In order to achieve the above object, claim 1 of the present invention provides a microwave component incorporating a microwave circuit, and a dielectric substrate having a circuit pattern connected to a signal line of the microwave component provided on an upper surface thereof. A case having a flat surface, a metal plate provided on the surface of the case, and at least a part of which is in contact with a lower surface having a ground terminal of the microwave component, and the metal plate And a fixing means for screwing the dielectric substrate and the microwave component to the case.

  According to the present invention, since the difference between the distance of the current path of the signal line connection and the distance of the current path of the ground connection can be minimized, the impedance matching can be improved.

  In the present invention, since the metal plate provided on the case extends at least to the lower part of the end of the microwave component, it is necessary to screw the dielectric and the metal plate to the case at a position close to the microwave component. No, there is an effect that the number of screws used can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIG. The configuration of the microwave circuit device of Embodiment 1 is as follows.

  A dielectric substrate 102 is attached to the metal plate 104, and the metal plate 104 is fixed to the case 105 with screws 103. The reason for this is that when ceramics are used for the dielectric substrate 102, the ceramics may be cracked if they are fixed to the case 105 with screws, and when other softer dielectrics are used, they are screwed to the case 105. This is because if the dielectric is deformed and the dielectric is deformed and cannot be reliably fixed, the dielectric is attached to the metal plate using an adhesive or the like, and the metal plate 104 and the case 105 are adhered. The dielectric substrate 103 is fixed to the case 105 by screwing.

  The metal plate 104 is configured to be in contact with a ground terminal provided on the lower surface of the microwave component 101 containing the microwave circuit and to cover the entire bottom surface of the microwave component 101.

  Furthermore, although the microwave component 101 is screwed to the case 105 with a screw 103, the metal plate 104 is also fastened together with the screw 103. Thus, the microwave component 101 and the case 105 are locked so as to sandwich the metal plate 104. Here, the microwave component 101 may be covered with a metal case. The microwave component 101 and the circuit pattern on the dielectric substrate 102 are connected by leads 106.

  4A is a cross-sectional view taken along line AA in FIG. A dielectric substrate 403 is attached to the metal plate 404 and screwed to the case 405. The metal plate 404 is in contact with the macro wave component 401. The first embodiment is configured to cover the entire bottom surface of the microwave component 401. Furthermore, although the microwave component 401 is screwed to the case 405 with a screw (not shown), the metal plate 404 is also fastened together with the screw. Thus, the microwave component 401 and the case 405 are locked so as to sandwich the metal plate 404 therebetween.

  When the current of the signal line connection flows in the direction of the arrow 406 in the order of the dielectric substrate 403-lead 402-microwave component 401-lead 402-dielectric substrate 403, the current of the ground connection is the metal plate 404-microwave component 401. -It flows in the direction of the arrow 407 in the order of the metal plate 404.

  As described above, the first embodiment of the present invention is configured to shorten the current path of the ground connection and minimize the difference between the distance of the current path of the signal line connection and the distance of the current path of the ground connection. ing. For this reason, compared with the conventional microwave circuit device, impedance mismatching is extremely difficult to occur, and the voltage standing wave ratio is improved.

  Further, in this embodiment, the case 305 does not have the base 307 shown in FIG. 3 and is flat, the metal plate 404 is flat and integrated, and the microwave component is placed thereon. In other words, it is not necessary to fix the screw at a position close to the microwave component, and the number of screws to be used can be reduced as compared with the conventional microwave circuit device.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG. The configuration of the microwave circuit device of the second embodiment is the same as the configuration of the first embodiment except that the metal plate 104 has a defective portion 201 on a part of the bottom surface of the microwave component 101.

  That is, the dielectric substrate 102 is attached to the metal plate 104, and the metal plate 104 is fixed to the case 105 with the screws 103. The metal plate 104 is configured to come into contact with the microwave component 101 containing the microwave circuit and to partially cover the bottom surface of the microwave component 101. The metal plate 104 has a defect portion 201 and is made of two metal plates that do not contact each other. Furthermore, although the microwave component 101 is screwed to the case 105 with a screw 103, the metal plate 104 is also fastened together with the screw 103. Thus, the microwave component 101 and the case 105 are locked so as to sandwich the metal plate 104. Here, the microwave component 101 may be covered with a metal case. The microwave component 101 and the circuit pattern on the dielectric substrate 102 are connected by leads 106.

  FIG. 4B is a cross-sectional view taken along line A′-A ′ in FIG. 2. A dielectric substrate 403 is attached to the metal plate 404 and screwed to the case 405. The metal plate 404 is in contact with the macro wave component 401. In the second embodiment, a part of the bottom surface of the microwave component 401 is covered. In other words, the metal plate 104 is formed of two metal plates that have the defect portion 201 and do not contact each other. A ground terminal (not shown) provided on the lower surface of the microwave component 401 is in contact with and electrically connected to these metal plates.

  Furthermore, although the microwave component 401 is screwed to the case 405 with a screw (not shown), the metal plate 404 is also fastened together with the screw. Thus, the microwave component 401 and the case 405 are locked so as to sandwich the metal plate 404 therebetween.

  When the signal line connection current flows in the direction of the arrow 408 in the order of dielectric substrate 403-lead 402-microwave component 401-lead 402-dielectric substrate 403, the current of the ground connection is metal plate 404-microwave component 401. -It flows in the direction of the arrow 409 in the order of the metal plate 404.

  In the above embodiment, the two metal plates are separate parts. However, if it is connected to the ground terminal on the lower surface of the microwave component, it may be a perforated metal plate in which a portion of the metal plate directly below the microwave component is lost except for that portion.

  As described above, the second embodiment of the present invention is configured to minimize the difference between the distance of the current path of the signal line connection and the distance of the current path of the ground connection. For this reason, compared with the conventional microwave circuit device, impedance mismatching hardly occurs, and the voltage standing wave ratio is improved. As described above, also in this embodiment, the metal plate extends to the lower surface of the microwave component, so that it is not necessary to screw it near the microwave component, and the number of screws to be used can be reduced.

  Furthermore, in this embodiment of the present invention, the metal plate is present only on a part of the lower surface of the microwave component, so that the amount of metal plate used can be reduced.

  As described above, in the present invention, as long as the metal plate is in contact with the ground terminal provided on the lower surface of the microwave component, the effect of the present invention can be obtained regardless of the form of the contact. Further, since the metal plate extends to the lower surface of the microwave component, the number of screws to be used can be reduced, and thus the manufacturing cost can be reduced.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea of the present invention.

1 is an external perspective view of a microwave circuit device according to a first embodiment of the present invention. It is an external appearance perspective view of the microwave circuit device in Embodiment 2 of the present invention. It is an external appearance perspective view of the microwave circuit device in a prior art. FIG. 3 is a cross-sectional view taken along line AA in FIG. 1 and a cross-sectional view taken along line A′-A ′ in FIG. 2. FIG. 4 is a sectional view taken along line BB in FIG. 3. FIG. 6 is an enlarged view of a portion C in FIG. 5.

Explanation of symbols

101, 301: microwave components,
102, 302: dielectric substrate,
103, 303a, 303b: screws,
104, 304: metal plate,
105, 305: Case,
106, 306: Lead,
201: Metal plate defect part.

Claims (4)

A microwave component containing a microwave circuit;
A dielectric substrate provided on the upper surface with a circuit pattern connected to the signal line of the microwave component;
A case with a flat surface,
A metal plate provided on the surface of the case, at least a part of which is in contact with the lower surface of the microwave component having a ground terminal;
Fixing means for screwing the metal plate and the dielectric substrate, and the microwave component to the case;
A microwave circuit device comprising:   The microwave circuit device according to claim 1, wherein the fixing means fastens the metal plate, the dielectric substrate, and the microwave component to the case with screws.   2. The microwave circuit device according to claim 1, wherein the metal plate has a defect portion immediately below the microwave component and is composed of two pieces.   4. The microwave circuit device according to claim 1, wherein the dielectric substrate is affixed on the metal plate.

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