JPH05335819A - Microwave integrated circuit - Google Patents

Abstract

PURPOSE:To obtain a microwave integrated circuit able to integrate a frequency adjustment device without losing the internal air-tightness. CONSTITUTION:A dielectric resonator 14 is fitted to a dielectric board 11 via a support base 13 and the entire parts are enclosed by a cover 15 and a base 16. The support base is formed into a hollow cylinder and a tuning screw 19 is inserted from the rear side of the base 16. Thus, the internal circuit is kept in air-tight state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance frequency adjusting mechanism for a microwave integrated circuit using a dielectric resonator.

[0002]

2. Description of the Related Art Generally, a dielectric resonator is smaller, lighter and cheaper than a cavity resonator and a coaxial resonator, and is widely used in a resonance circuit such as an oscillator and a filter formed by a microwave integrated circuit. ing. As shown in the figure, a resonance circuit using a dielectric resonator has a case (1) that forms a shield case and a substrate (2) that serves as a lid for the case (1). ), The dielectric resonator (4) is mounted on the dielectric substrate (3) mounted on the support substrate (5),
A strip line (6) magnetically coupled to the dielectric resonator (4) is formed on a dielectric substrate (3), and an input / output terminal (not shown) is connected to each strip line (6).
In the case of an oscillator, the magnetic field coupling strength determined by the distance between the dielectric resonator (4) and each strip line (6) and the dielectric resonator on the strip line (6) from a microwave semiconductor element (not shown). When the distance to the magnetic field coupling point of (4) is properly set so as to satisfy the oscillation condition in accordance with the negative resistance characteristic of the semiconductor element, the dielectric resonator (4) oscillates at the resonance frequency, The oscillation output can be taken out from the output terminal.

In such a device, the resonance frequency is caused by a dimensional error of the dielectric resonator (4), a variation in material characteristics, and a shift in the positional relationship between the microstrip line (6) and the dielectric resonator (4). However, a constant value as a designed value cannot always be obtained due to a positional shift between the inner wall of the case (1) and the dielectric resonator (4), a variation in characteristics of active elements used in the case of an oscillator, or the like. Therefore, some mechanism that can continuously change the resonance frequency is required.

Such an adjusting mechanism is disclosed in, for example, Japanese Patent Laid-Open No. 62-200991.
A screw hole (7) is provided in the ceiling part of the case (1) and the tuning screw (8) is screwed in, and the screwing amount is changed to adjust the distance between the dielectric resonator (4) and the tuning screw (8). A mechanism for finely adjusting the oscillation frequency by changing it is adopted.

[0005]

However, the tuning screw (8) inserted in the screw hole (7) does not have a function of hermetically sealing the inside of the case (1).
Therefore, when the tuning screw (8) is provided, the airtightness of the inside is lost, and it is necessary to protect the internal element again in order to compensate for this.

As a conventional method for doing this, the surface is coated with Au plating or glass coat to protect the strip line (6), and the package is used to protect active elements.
There are methods such as using a di-sealed product or resin-sealing after bonding, but there is a drawback that the cost becomes high. Further, a method of adjusting the frequency and then sealing the mounting portion of the tuning screw (8) with a resin, or a method of adjusting the frequency only by adjusting the internal circuit and eliminating the tuning screw (8) are possible. Since the resonance frequency may fluctuate depending on the load to be connected, means for adjusting the frequency is required even after the load is connected.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and the supporting base of the dielectric resonator is formed into a hollow cylindrical shape, and one of the cylinders is bonded to the dielectric resonator to form a lid. The tuning screw is inserted from the other opening to provide a frequency adjusting mechanism that does not impair the airtightness of the internal circuit.

[0008]

According to the present invention, the tuning screw (19) is inserted into the cylindrical support base (13), and the hollow portion of the support base (13) is sealed with the dielectric resonator (14). The internal circuit is kept in an airtight state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIG. Referring to FIG. 1, in the case of an oscillator, a strip line (12) is formed by screen printing on the surface of a dielectric substrate (11) having a high dielectric constant such as ceramic and having a plate thickness of 1.0 to 2.0 mm. Is GaAs MES
A microwave semiconductor element (not shown) such as an FET is mounted on a bare chip and wire bonded. A hollow cylindrical support (13) is adhered near the center of the dielectric substrate (11), and a ceramic dielectric resonator (14) is adhered on the support (13) to form a strip line (12). Magnetically coupled with. The cover (15) is made by processing a metal plate into a flat-bottomed container, and is completely sealed except for the opening surface. The cover (15) is installed so as to cover the dielectric substrate (11) mounted on the metal substrate (16), and the peripheral edges are hermetically joined by seam welding.

The hollow inside of the support (13) is completely isolated from the inside of the cover (15) by adhering both ends to the dielectric resonator (14) and the dielectric substrate (11). .. A through hole (17) is provided in the dielectric substrate (11) corresponding to the hollow inside of the support base (13), and a female screw (18) is cut in the substrate (16) continuously with the through hole. A metallic tuning screw (19) as a conductor rod is inserted into the support base (13) through the female screw (18) and the through hole (17), and the tuning screw (19) is screwed in. By changing the amount,
The tip of the screw (19) and the dielectric resonator (1
The resonance frequency can be adjusted by changing the distance from 4). After adjustment, turn the tuning screw (1
The position of the tuning screw (19) is fixed by the nut (20) screwed into 9). (21) is a washer. FIG. 2 is an example in which the device of FIG. 1 is connected to an external circuit. A mounting screw (22) integrated on the back surface of the board (16) is inserted into a mounting hole of a circuit board (23) made of Teflon or the like, and the device is fixed by a washer and a nut (24). The input / output terminals (25) fixed through the dielectric substrate (11) and the substrate (16) and electrically connected to the strip line (12) on the surface of the dielectric substrate (11) penetrate the circuit substrate (23). It is inserted into the hole and soldered to another strip line (26) formed on the surface of the circuit board (23). The tuning screw (19) projects through a through hole provided in the circuit board (23).

According to the first embodiment of the present invention constructed as described above, the tuning screw (19) is inserted into the hollow inside of the support base (13), and the dielectric resonator (14) and the tuner are installed. -The resonance frequency can be adjusted by changing the distance from the screw (19). On the other hand, one end of the support base (13) is completely covered with the dielectric resonator (14),
Since the other end is bonded to the dielectric substrate (11), the hollow inside of the support base (13) is exposed to the outside air, and the outside of the support base (13), that is, the inside of the case (15) can be shielded from the outside air. Therefore, the strip line (12) installed on the surface of the dielectric substrate and the element to be protected such as the microwave semiconductor element can be kept completely in an airtight state. The dielectric resonator (14) that is exposed to the outside air inside the hollow inside of the support is not an element that requires hermetic sealing.

Therefore, the device of the present invention is capable of hermetically sealing the internal elements at the same time as providing the frequency varying means by the tuning screw (19). Also,
The tuning frequency (19) can be used to adjust the resonance frequency even when an external circuit is connected.
Furthermore, when designing the circuit of the external circuit, the circuit board (2
3) is connected and measurement and adjustment are repeated to determine an appropriate design value for the strip line (26) of the external circuit. In this case, according to the configuration of the present application, the tuning screw is used. (19) and circuit board (2
Since the strip line (26) of 3) is oriented in the same direction, there is also an advantage that adjustment is easier than using the conventional device.

In the first embodiment, the nut (20) of the tuning screw () is provided on the board (16), but as shown in FIG. 3, the circuit board (23) is provided.
The nut (20) may be provided on the upper part.

[0014]

As described above, according to the present invention, there is an advantage that the frequency adjusting mechanism by the tuning screw (19) can be incorporated while maintaining the airtightness of the internal elements.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a first embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining a state in which an external circuit is connected.

FIG. 3 is a sectional view for explaining a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional example.

Claims (2)

[Claims] 1. A dielectric resonator is attached via a support base,
A dielectric substrate having a resonant circuit coupled to this dielectric resonator is fixed on a plate-shaped substrate, and the dielectric substrate is sealed inside by the substrate and a container-shaped cover bonded to the substrate. In the microwave integrated circuit described above, the support base has a cylindrical shape, one opening of the support base is sealed by the dielectric resonator, and the dielectric substrate corresponding to the other opening and the through hole in the substrate. And a conductor rod capable of adjusting a distance from the dielectric resonator is inserted into the support through the through hole. 2. The microwave integrated circuit according to claim 2, wherein the conductor rod is a male screw, and a female screw is fixed to the dielectric substrate.