JPH11205013A - Impedance matching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To match with the impedance of the input/output pin of IC of a small pin interval by lowering the impedance, when the conductor pattern width of a substrate is limited. SOLUTION: A conductor (ground) pattern 7 on the lower surface of the part of IC4 of the substrate 1 of a glass resin, etc., is removed, and this part is fitted to a housing 8 by inserting the substrate consisting of ceramic, etc. A substrate 10 is removed of a part corresponding to an IC4 of a conductor pattern 11 on its top surface. Thereby, the dielectric constant is increased by the total sum of the substrates 1 and 10, so that the impedance of conductor patterns 2 and 3 can be lowered, to match with the input/output impedance of IC4 even if the widths of the patterns 2 and 3 to be connected are small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impedance matching device, and more particularly to an impedance matching device for mounting an IC (integrated circuit) of a high-frequency circuit on a substrate.
It relates to matching the input and output impedance of C.

[0002]

2. Description of the Related Art Satellite broadcasting (BS) or communication satellite (C)
In the converter circuit and the like in S), a glass circuit material is mainly used for a printed circuit board in terms of mechanical strength and cost, and the circuit is formed into an IC to reduce the size. FIG. 4 is a side sectional view of an example of a conventional high-frequency circuit device, in which an IC 4 is disposed on a first substrate 1 and attached to a housing 8. Reference numeral 2 denotes an input-side conductor pattern, and reference numeral 3 denotes an output-side conductor. Pattern, 5
Is an input pin of the IC 4, and 6 is an output pin. The input and output impedances of the IC 4 are, for example, 50 ohms, respectively. In order to minimize the signal loss, impedance matching is required, and it is desirable that the conductor patterns 2, 3 are both 50 ohms. However, the IC 4 has a small pitch between pins for miniaturization and naturally limits the width of the conductor patterns 2 and 3, and as a result, the impedance becomes higher than 50 ohms and the impedance cannot be matched. The impedance of the conductor pattern is greatly affected by the thickness of the board and the relative permittivity of the board. To reduce the impedance, a board with a small thickness and a high relative permittivity can be used, but the thinning of the board requires mechanical strength. Ceramic substrate with high relative dielectric constant (specific dielectric constant of about 10, about 3.5 for glass resin)
Etc. are expensive.

[0003]

SUMMARY OF THE INVENTION In view of the foregoing, the present invention has been made to use a substrate having a high relative dielectric constant in combination with a required portion of a substrate made of a glass resin or the like so as to achieve impedance matching at relatively low cost. Aim.

[0004]

In order to achieve the above object, in the impedance matching device of the present invention, a microwave signal processing circuit is provided on a first substrate, and a signal processing circuit portion of the first substrate is provided. The conductor pattern on the lower surface is removed, a second substrate having a higher dielectric constant than the first substrate is attached to the portion, and the second substrate is attached to a metal housing surface.

Alternatively, the conductor patterns on the lower surfaces of the input terminal portion and the output terminal portion of the signal processing circuit of the first substrate are removed, and a third substrate having a higher relative dielectric constant than the first substrate is attached to these locations. Attach it to the metal housing surface.

The second substrate or the third substrate has no conductor pattern on both the upper and lower surfaces.
Either a conductor pattern is provided on the lower surface and no conductor pattern is provided on the upper surface, or a conductor pattern is provided on the lower surface and the conductor pattern of a portion corresponding to the conductor pattern removed portion of the first substrate on the upper surface is removed. Shall be.

[0007] The conductive pattern portion on the upper surface of the second substrate or the third substrate is bonded to the conductive pattern portion of the first substrate with a conductive adhesive, or the conductive pattern portion on the lower surface of the second substrate or the third substrate. The part is adhered to the housing surface with a conductive adhesive.

Further, a second substrate or a third substrate is provided on the housing surface.
A concave portion corresponding to the shape of the substrate is formed, and the second substrate or the third substrate is embedded in the concave portion so that the lower surface of each substrate is in close contact with the housing surface.

Alternatively, the lower surface of the first substrate is cut in accordance with the shape of the second substrate or the third substrate, the second substrate or the third substrate is fitted, and is brought into close contact with the first substrate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. 1A and 1B are main part configuration diagrams of an embodiment of the impedance matching device according to the present invention, wherein FIG. 1A is a top view, FIG. 1B is a side sectional view, and FIG. 1C is a bottom view of the first substrate 1. In the figure, reference numeral 1 denotes a glass-resin-based material (with a relative dielectric constant of about
3.5), etc., 2 is an input side conductor pattern, and 3 is an output side conductor pattern. Reference numeral 4 denotes an IC of a microwave band signal processing circuit, reference numeral 5 denotes a signal input pin, reference numeral 6 denotes a signal output pin, and the input / output impedance is, for example, 50 ohms. Reference numeral 7 denotes a conductor pattern on the lower surface of the first substrate 1.
Reference numeral 8 denotes a metal housing, and 9 denotes screws for attaching the substrate 1 to the housing 8. 10 is the second such as ceramic substrate (relative permittivity about 10)
Reference numeral 11 denotes a conductor pattern on the upper surface, and 12 denotes a conductor pattern on the lower surface.

The first substrate 1 is formed by removing the conductor pattern (ground pattern) 7 on the lower surface of a portion corresponding to the IC 4 (shown by a dotted line in FIG. 1C), and the second substrate 10 is, for example, shown in FIG. Thus, the conductor pattern of the portion A corresponding to the width of the IC 4 is removed, and the conductor pattern (ground pattern) 12 on the lower surface is left, and the first substrate 1 is mounted on the housing 8 with the second substrate 10 interposed therebetween. As a result, the conductor patterns 2 and 3 of the portion connecting the input / output pins 5 and 6 of the IC 4 are located between the conductor pattern 12 and the substrate 1 (relative permittivity of about 3.5) and the substrate 10 (relative permittivity of about 10). Overlap, the relative dielectric constant becomes higher than that of the first substrate 1 as a whole, the impedance of the conductor patterns 2 and 3 decreases, and it becomes easy to match with the input / output impedance of the IC 4.

The mounting position of the second substrate 10 on the lower surface of the first substrate 1 may be cut in accordance with the shape of the second substrate 10, and the second substrate 10 may be fitted to the second substrate 10 for easy mounting. Or,
A recess may be formed in the housing 8 according to the shape of the second substrate 10, and the second substrate 10 may be embedded in the recess to facilitate positioning. At the time of attachment, the conductive pattern 11 on the upper surface of the second substrate 10 may be bonded to the first substrate 1 with a conductive adhesive, or the conductive pattern 12 on the lower surface of the second substrate 10 may be electrically conductive. It may be adhered to the housing 8 with an adhesive. By bonding the conductive pattern with a conductive adhesive, a reliable conductive effect can be obtained.

In the above description, the second substrate 10 has been described as having a conductor pattern (ground pattern) on both upper and lower surfaces. However, a substrate having no conductor pattern on the upper surface or a substrate having no conductor pattern on both upper and lower surfaces may be used. . This is because even if there is no conductor pattern 11 on the upper surface of the second substrate 10, the conductor pattern 7 on the lower surface of the first substrate 1 also serves this role, and there is no conductor pattern 12 on the lower surface of the second substrate 10. However, since the housing 8 performs this function, the cost can be reduced as compared with the case having the conductor pattern. However, the presence of the conductor pattern 11 or the conductor pattern 12 provides a stable grounding effect.

FIG. 3 is a side view of a main part of another embodiment of the impedance matching device according to the present invention, in which the second substrate 10 is divided into two third substrates 21, and the input pins 5 and the output pins of the IC 4 are separated. Since it is separately attached to the portion 6, the amount of use of a relatively expensive ceramic substrate can be reduced, and the cost can be reduced. In addition, the thing with and without the conductor pattern 22 on the upper surface of the third substrate 21, the thing with and without the conductor pattern 23 on the lower surface, the lower surface of the first substrate 1 is cut, the housing 8 is cut into a concave shape, Conditions and effects such as bonding the conductor pattern with a conductive adhesive are the same as those of the second substrate 10, and the description is omitted because the contents are duplicated.

[0015]

As described above, according to the impedance matching device of the present invention, a substrate having a high relative dielectric constant such as ceramic is partially provided on the back surface of a substrate having a low relative dielectric constant such as a glass resin. By overlapping, the relative dielectric constant can be increased as a whole, and the impedance can be reduced even when the width of the conductor pattern of the substrate is limited, and the I-pin having a narrow pin interval can be used.
It can be matched with input / output impedance such as C.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of an embodiment of an impedance matching device according to the present invention.

FIG. 2 is an example of a second substrate.

FIG. 3 is a main part configuration diagram of another embodiment of the impedance matching device according to the present invention.

FIG. 4 is a main part configuration diagram of an example of a conventional high-frequency circuit device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 input side conductor pattern 3 output side conductor pattern 4 IC5 input pin 6 output pin 7 conductor pattern on the lower surface of a 1st board 8 housing | casing 10 2nd board | substrate 11 conductor pattern on the upper surface of a 2nd board 12 second Conductor pattern on lower surface of substrate 21 Third substrate 22 Conductor pattern on upper surface of third substrate 23 Conductor pattern on lower surface of third substrate

Claims (9)

[Claims] 1. A signal processing circuit having a microwave band disposed on a first substrate and attached to a metal housing surface, wherein a conductor pattern on a lower surface of a signal processing circuit portion of the first substrate is removed. An impedance matching device in which a second substrate having a higher dielectric constant than the first substrate is attached to the location. 2. A signal processing circuit in a microwave band disposed on a first substrate and attached to a metal housing surface, wherein the lower surface of an input terminal portion and an output terminal portion of the signal processing circuit on the first substrate. An impedance matching device comprising a third substrate having a higher relative dielectric constant than the first substrate attached to a corresponding portion of the third substrate. 3. The impedance matching device according to claim 1, wherein the second substrate or the third substrate does not have a conductor pattern on both upper and lower surfaces. 4. The impedance matching device according to claim 1, wherein the second substrate or the third substrate has a conductor pattern on a lower surface and does not have a conductor pattern on an upper surface. 5. The second substrate or the third substrate has a conductor pattern on a lower surface, and a conductor pattern in a portion corresponding to a conductor pattern removed portion of the first substrate on the upper surface is removed. 3. The impedance matching device according to 2. 6. The impedance matching device according to claim 5, wherein the conductive pattern portion on the upper surface of the second substrate or the third substrate is bonded to the conductive pattern portion of the first substrate using a conductive adhesive. 7. The impedance matching device according to claim 4, wherein the conductive pattern portion on the lower surface of the second substrate or the third substrate is bonded to the housing surface using a conductive adhesive. 8. A method according to claim 1, wherein a concave portion corresponding to the shape of said second substrate or said third substrate is formed in said housing surface, and said second substrate or said third substrate is embedded in said concave portion. 3,
8. The impedance matching device according to 4, 5, 6, or 7. 9. The method according to claim 1, wherein the lower surface of the first substrate is cut in accordance with the shape of the second substrate or the third substrate, and the second substrate or the third substrate is fitted. 4,
The impedance matching device according to 5, 6, or 7.