JPH03216004A - Directional coupler - Google Patents

Abstract

PURPOSE:To evade the effect of case resonance to be occasionally caused based on the grounding condition of substrate at an operating frequency band and at the time of containing a metallic case and to improve the degree of integration of components by providing a contact in contact with the cover of metallic case of a conductor side on one side of a dielectric board. CONSTITUTION:A coupling circuit section 3 realizing the characteristic of the directional coupler is provided on a dielectric circuit board 1, a dielectric board 2 provided with a ground conductor 6 to one side of the circuit section 3 and a throughhole 8 provided to both the boards 1, 2 is provided to connect both the boards 1, 2 to ground in common. Moreover, a contact 7 is provided to the ground conductor 6 to one side of the dielectric board 2 and the contact 7 is brought into contact with a metallic case cover 9. Since the ground condition at an operating frequency band from the metallic case cover is satisfied, the ground impedance of both the boards is made equal and even the effect of the case resonance to be caused at the time of containing the metallic case is evaded to realize the excellent characteristic.

Description

[Detailed Description of the Invention] [-Industrial Applications] The present invention relates to a microwave integrated circuit, and particularly to a directional coupler configured as a planar circuit. [Prior Art] Conventionally, in a microwave device, Directional couplers may be used to detect or distribute high frequency signals.

Generally, a microwave band directional coupler configures a coupling circuit by coupling a main signal line and a sub-signal line, and the coupling degree is determined by the distance between the couplings, and the distance in the signal propagation direction is λg / 4
The frequency band to be used is determined by selecting λg or 3/4λg. In recent years, from the viewpoint of integrating microwave circuits, circuits that are small and configured on a flat surface are desired, and it is required to mount circuits with various functions on the same substrate. In general, there is a configuration method using microstrip lines, but in this case, although it is superior in terms of integration in terms of implementation, the directivity as the performance of the original directional coupler is dB (0 to 2 dB) L cannot be obtained. Also, is there a method of constructing a tri-plate structure, in other words, by pasting together two bases, connecting them to a connection circuit, and sandwiching them between ground conductors? On the other hand, it is a big constraint when it comes to mounting.In order to solve this drawback of the tri-plate groove structure, we installed a board with a circuit pattern and a dielectric board with a conductor on one side only in the connecting circuit part. By doing so,
A structure that realizes a triplate structure and allows elements to be placed in other parts is conceivable. In that case, a through hole is provided for the purpose of high-frequency grounding in the coupling circuit part of the board with the circuit pattern and in the dielectric board with the single-sided conductor, so that the ground potential of both boards is equalized. .

[Problem to be solved by the invention]

In the above-mentioned conventional directional coupler, as the operating frequency becomes higher, especially in the microwave frequency range, the through holes become effective as actance elements, resulting in insufficient grounding and damage to the dielectric substrate on the mounting side. Since it is grounded to the case through a single-sided conductor or a through hole on the circuit pattern side, there is a drawback that the grounding impedance of both boards is not equal. Another disadvantage is that when housed in a metal case, due to the above-mentioned reason, the conductor on one side of the dielectric substrate on the mounting side is not sufficiently grounded, which makes it easy to couple with the case resonance mode, leading to deterioration of the characteristics of the directional coupler. There is.

[Means to solve the problem]

The present invention provides a coupling circuit section formed by two parallel line patterns on a flat circuit board, a dielectric substrate having a conductor on one side and mounted only on the coupling circuit section, and the circuit board. and a through hole formed in the dielectric substrate for common grounding of the two substrates, the directional coupler having a through hole provided on the conductor side of the one side of the dielectric substrate and of a metal case. It is equipped with a contact that makes contact with the cover.

Moreover, the directional coupler of the present invention has a shape in which the contactor contacts the cover of the metal case at at least two places.

,Example] Next, the present invention will be explained with reference to drawing p.

1 and 2 are an exploded perspective view and a cross-sectional view of an embodiment of the present invention.

This embodiment has a coupling circuit part 3 formed by two parallel line patterns on a flat dielectric circuit board 1, and a dielectric body having a one-sided ground conductor 6 and mounted only on the coupling circuit part 3. A through hole 8 is formed in the substrate 2, the dielectric circuit board Wi1, and the dielectric substrate 2 for common grounding of both substrates.
Further, one side of the dielectric substrate 2 has a ground conductor #. The contactor 7 is provided on the 6 side and comes into contact with the metal cage 9 when housed in the metal cage 10.

That is, as shown in FIGS. 1 and 2, a dielectric circuit board 1
A coupling circuit section 3 that realizes the characteristics of a directional coupler is provided on the top, and a dielectric substrate 2 having a one-sided ground conductor 6 is mounted on the circuit section, and a through hole 8 provided on both substrates or a coupling circuit section 3 that realizes the characteristics of a directional coupler is provided. It has a structure in which it is provided for common grounding and further includes a contactor 7 on a one-sided ground conductor 6 of the dielectric substrate 2 to be mounted.

According to this embodiment, the contactor 7 provided on the single-sided conductor side of the dielectric substrate 2 comes into contact with the metal case force bar 9, so that the grounding condition in the operating frequency range can be adjusted from the metal case force bar side. This makes it possible to equalize the grounding impedance of both boards, and is also effective in avoiding the effects of case resonance that occurs when the metal case is stored. Good characteristics can be achieved.

In this embodiment, the shape of the contact 7 is such that it contacts the metal case force bar 9 at two points, but this is to stabilize the frequency characteristics rather than contacting at one point, and the shape of the contact 7 is such that it contacts the metal case force bar 9 at two points. It may also be shaped like this. Further, in order to ensure the contact between the contact 7 and the metal case force bar 9, the contact 7 may be made to have spring properties, for example.

〔Effect of the invention〕

As explained above, in order to realize the triple-plate ellipse for microwave integration, the present invention provides a circuit pattern on the single-sided conductor side of a dielectric substrate mounted only on the circuit portion of the substrate portion of the circuit pattern. By having the structure of the contactor, it is possible to avoid the effects of the grounding conditions of both boards in the operating frequency band and the booth resonance that may occur when storing the metal gates. High frequency parts as well
It can be mounted in areas other than the combined circuit part on the same circuit board.
It is effective in increasing the degree of integration of parts.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view of this embodiment. 1... Dielectric circuit board, 2... Dielectric substrate, 3...
・Coupling circuit section, 4...Element, 5...Grounding conductor, 6.
... Single-sided ground conductor, 7... Contact, 8... Through hole, 9... Metal case force bar, 10... Metal case.

Claims (2)

[Claims] 1. a coupling circuit section formed by two parallel line patterns on a flat circuit board; a dielectric substrate having a conductor on one side and mounted only on the coupling circuit section; and the circuit board and the dielectric substrate. In the directional coupler, the through hole is provided on the conductor side of one side of the dielectric substrate and is in contact with the cover of the metal case. A directional coupler characterized by comprising a contactor. 2. 2. The directional coupler according to claim 1, wherein the contact has a shape that makes contact with the cover of the metal case at at least two places.