JPH04372205A - Printed circuit board - Google Patents

Abstract

PURPOSE:To improve the noise characteristic and to make the performance high by ensuring the electric and mechanical shield. CONSTITUTION:A shield case 12 is provided onto a synthetic resin made board 10 so as to cover a microwave integrated circuit imbeded and joined on the board 10 and the shield case 12 connects to ground so as to be set to the same potential as that of the synthetic resin made board 10 and a dielectric board 11, then the dielectric board 11 is shielded electrically and mechanically to prevent external leakage of a signal and invasion of an external signal, and the attachment of external dust or the like is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board device used to construct a microwave integrated circuit such as a microwave band amplifier circuit.

0002

[Prior Art] As is well known, microwave integrated circuits are
A metal pattern such as a microstrip conductor is formed on the surface of a dielectric substrate made of ceramic such as alumina having a high dielectric constant, and a ground conductor made of a metal film is formed on the back surface of this dielectric substrate. The dielectric substrate on which this microwave integrated circuit is formed is mechanically fragile due to its material, and if it is directly fixed to a case or the like with screws or the like, the substrate will crack or peel. Therefore, with such a dielectric substrate, a microwave integrated circuit is formed using the circuit board device shown in FIG. That is, in the figure, 1 is a synthetic resin substrate such as a glass fiber epoxy resin substrate, and a concave accommodating portion 1a is provided on one side of the substrate. A dielectric substrate 2 on which a metal pattern 2a forming a microwave integrated circuit is formed is accommodated in the accommodation portion 1a and bonded using an adhesive or the like. A mounting hole 1b is formed in the synthetic resin substrate 1, and after being accommodated in a metal case 3 as shown in FIG. 8, it is fixed with a screw 4 using the mounting hole 1b. However, the circuit board device described above has the following problems because the area around the high frequency circuit is electrically and mechanically open due to its structure.

(1) In order to handle microwave band signals, signals may leak to the outside from the metal pattern 2a formed on the dielectric substrate 2, or may be combined with signals existing in the space near the metal pattern 2a. The problem was that the noise characteristics were very poor. This means noise (spurious) in the transmitted signal.
This causes deterioration in performance, and is a major problem especially in high frequency bands or when a large number of high frequency circuits are mounted on the same board.

As a result, when formed around a circuit that requires low loss, such as a resonant circuit of an oscillator, it becomes difficult to ensure low loss characteristics due to the electrically open state. . Furthermore, when a filter is configured using a microstrip line, it is difficult to achieve reliable electromagnetic sealing, resulting in increased pass loss and deterioration of band rejection characteristics. Also, if you configure an amplifier,
Unnecessary oscillation occurs, making it difficult to obtain desired performance. (2) There is a problem in that dust, dirt, etc. adhere to the metal pattern 2a, leading to an increase in transmission loss and deterioration of performance.

[0005]

[Problems to be Solved by the Invention] As stated above, conventional circuit board devices have very poor noise characteristics and are susceptible to dust, etc., which leads to a decline in the performance of microwave integrated circuits. I had a problem.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a circuit board device that has a simple configuration, can improve noise characteristics, and has improved performance characteristics. purpose.

[0007]

[Means for Solving the Problems] The present invention provides a dielectric substrate having a microwave integrated circuit formed on one side and a ground conductor formed on the other side, and a buried structure in which the dielectric substrate is accommodated on one side. A synthetic resin substrate is formed with a concave housing portion and a ground conductor is formed on the other side, and the ground conductor of this synthetic resin substrate and the ground conductor of the dielectric substrate are connected and set to the same potential. a grounding means, which is attached to the synthetic resin substrate so as to cover the dielectric substrate embedded in the housing portion of the synthetic resin substrate, and is connected to a grounding conductor of the synthetic resin substrate and a grounding means of the dielectric substrate; The circuit board device includes a lid body formed of a conductor and connected to the conductor.

[0008]

[Function] According to the above structure, the dielectric substrate bonded to the housing part of the constituent resin substrate is electrically and mechanically shielded by the lid, thereby preventing leakage of signals from the outside and interference of signals from the outside. The intrusion of dust is reliably prevented, thereby improving noise characteristics, and the adhesion of dust and the like from the outside is also prevented. Therefore, the formation of high performance microwave integrated circuits is realized.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a circuit board device according to an embodiment of the present invention. In the figure, reference numeral 10 denotes a synthetic resin substrate, and a concave accommodating portion 10a is formed on one side. This housing part 1
A dielectric substrate 11 is housed in Oa, and is bonded to the dielectric substrate 11 by using, for example, a conductive adhesive so as to be embedded therein. This dielectric substrate 11 has a metal pattern 11a forming a microwave integrated circuit such as an oscillator formed on one side, and a ground conductor (not shown for reasons of illustration) formed on the other side. These are interconnected via through holes (not shown for illustration purposes). A shield case 12, for example, is attached as a lid to one side of the synthetic resin substrate 10 so as to cover the dielectric substrate 11. Shield case 12
is formed of a conductive material such as a tin-plated steel plate into a shape that takes into account waveguide mode suppression, and a flange portion 12a for attachment is formed at its base. This collar portion 12a has a mounting hole 12.
b is formed.

Furthermore, a metal pattern 10b such as a microstrip conductor to be connected to an external device (not shown) is formed on one side of the synthetic resin substrate 10, and this metal pattern 10b is similar to the metal pattern 11a of the dielectric substrate 11. and are connected using a connecting member 13 such as copper foil. A ground conductor (not shown) is formed in the housing portion 10a of the synthetic resin substrate 10, and this ground conductor (not shown) is connected to the through hole 10.
It is connected to a ground conductor (not shown) formed in the other direction via c.

Furthermore, a through hole 10d for grounding the case is formed at a predetermined position on the synthetic resin substrate 10, corresponding to the mounting hole 12b of the flange 12a of the shield case 12. One end of this through hole 10d is connected to a ground conductor (not shown) formed on the other surface of the synthetic resin substrate 10.

In the above configuration, the dielectric substrate 11 joined to the housing portion 10a of the constituent resin substrate 10 has its metal pattern 11a connected to the metal pattern 10b of the synthetic resin substrate 10 via the connecting member 13, Its ground conductor (
(not shown) is connected to a ground conductor (not shown) of the housing portion 10a and a ground conductor (not shown) on the other side of the synthetic resin substrate 10 via a through hole 10c. Here, the shield case 12 is electrically connected to the through hole 10d via the screw 14 installed in the attachment hole 12b of the flange 12a, and the other side of the synthetic resin substrate 10 is connected to the through hole 10d through the through hole 10d. are connected to a ground conductor (not shown) and set to the same potential. As a result, the shield case 12 electrically and mechanically shields the microwave integrated circuit on the dielectric substrate 11, and prevents noise such as radiation of unnecessary signals into the surrounding space and intrusion of unnecessary signals from the surrounding space. It also prevents dirt and dust from entering from outside.

The synthetic resin substrate 10 to which the dielectric substrate 11 and shield case 12 are attached is housed in a metal case 15, for example, as shown in FIG. 2, and is attached to the metal case using the mounting hole 10e. It is attached using screws. At this time, the metal pattern 10 of the constituent resin substrate 10
b is connected to, for example, a connector (not shown) provided on the metal case 14, and is connected to the external device (not shown).

As described above, the above-mentioned circuit board device is provided with the shield case 12 so as to cover the microwave integrated circuit embedded and bonded on the synthetic resin substrate 10, and this shield case 12 is connected to the synthetic resin substrate 10 and the dielectric substrate 10. It is configured to be grounded to the same potential as the body substrate 11. According to this, the dielectric substrate 11 is electrically and mechanically shielded by the shield case 12, thereby reliably preventing leakage of signals to the outside and intrusion of signals from the outside, and improving noise characteristics. At the same time, adhesion of dust, etc. from the outside is reliably prevented. Therefore, a configuration of a microwave integrated circuit that requires reliable shielding of the periphery of a resonator such as an oscillator or a filter using a dielectric resonator can be realized. Further, when a filter is configured, the characteristics can be improved, and when an amplifier is configured, oscillation prevention can be reliably realized and performance can be easily improved.

[0016] In the above embodiment, the shield case 1
2 is provided with a flange portion 12a, and the flange portion 12a is used to attach to the synthetic resin substrate 10 and to connect to the grounding through hole 11d, but the present invention is not limited thereto. Protrusions 12c are provided as shown in FIG.
It is also possible to utilize this protrusion 12c and insert it into a grounding through hole 10d formed in the synthetic resin substrate 10 and solder it to achieve support and grounding.

Further, in the above embodiment, the constituent resin substrate 1
Although the dielectric substrate 11 on the top of the dielectric substrate 10 is covered with a separate shield case 12, the present invention is not limited to this, and for example, as shown in FIG.
A recess 15a that also serves as a lid body is provided in the metal case 15 that accommodates the
A shield structure may be constructed in which the recess 15a covers the dielectric substrate 11.

Further, in each of the above embodiments, the case where one dielectric substrate 11 is disposed on the synthetic resin substrate 10 has been explained, but the present invention is not limited to this, and for example, as shown in FIG. It is also possible to arrange the substrates 11 and cover each with a shield case 12. In this case, as shown in FIG. 6, it is also possible to arrange dielectric substrates 11 on both sides of a synthetic resin substrate 10. When dielectric substrates 11 are disposed on both sides of this synthetic resin substrate 10, the shield case 12 that covers the dielectric substrate 11 on one side is accommodated in a stepped portion 15b formed on the mounting surface of the metal case 10. As a result, there is no problem with installation.

Note that each shield case 12 in FIGS. 5 and 6 also has a synthetic resin substrate 1 as described above.
It is electrically connected to a ground conductor (not shown) of 0 and is configured to be connected to have the same potential.

Furthermore, in each of the above embodiments, the dielectric substrate 11 on which the microwave integrated circuit is formed is formed on the synthetic resin substrate 10.
Although the description has been made in the case where only a bias circuit and a digital control circuit are disposed on the synthetic resin substrate 10, the structure is not limited to this, and a structure may be adopted in which low frequency circuits such as a bias circuit and a digital control circuit are mixed and mounted on the synthetic resin substrate 10. is also possible. Therefore, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit of the invention.

[0021]

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a circuit board device that has a simple configuration, can improve noise characteristics, and has high performance characteristics. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a circuit board device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the attached state of FIG. 1;

FIG. 3 is a diagram showing another embodiment of the invention.

FIG. 4 is a diagram showing another embodiment of the invention.

FIG. 5 is a diagram showing another embodiment of the invention.

FIG. 6 is a diagram showing another embodiment of the invention.

FIG. 7 is a diagram showing a conventional circuit board device.

FIG. 8 is a diagram showing the attached state of FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10...Synthetic resin substrate, 10a...Accommodating part, 10b...Metal pattern, 10c, 10d...Through hole, 10e...Mounting hole, 11...Dielectric substrate, 11a...Metal pattern, 12
...Shield case, 12a...Brim part, 12b...Mounting hole,
12c... Protrusion, 13... Connection member, 14, 16... Screw,
15...metal case, 15a...recessed part, 15b...stepped part.

Claims (2)

[Claims] 1. A dielectric substrate having a microwave integrated circuit formed on one side and a ground conductor formed on the other side, and a concave housing portion formed on one side to accommodate and bond the dielectric substrate. a synthetic resin substrate with a ground conductor formed on the other surface; a grounding means for connecting the ground conductor of the synthetic resin substrate and the ground conductor of the dielectric substrate to set them to the same potential; It is attached to the synthetic resin substrate so as to cover the dielectric substrate buried in the substrate housing part, and is formed of a conductor connected to the ground conductor of the synthetic resin substrate and the ground conductor of the dielectric substrate. 1. A circuit board device comprising: 2. The circuit board device according to claim 1, wherein the synthetic resin substrate has a low frequency circuit mounted thereon together with a housing portion to which the dielectric substrate is bonded.