JPH06204707A - Resonance frequency adjusting method for dielectric filter - Google Patents

Abstract

PURPOSE:To adjust the resonance frequency of a small-sized dielectric filter. CONSTITUTION:Input/output of the filter composed of a 1st dielectric substrate 21 and a 2nd dielectric substrate is directly executed at an impedance matching point, and a terminal electrode 28 is formed to a flank close to the flank of the substrate. The resonance frequency is adjusted by varying a distance between the terminal and an outer conductor. Normally a conductor film is trimmed for fine-adjustment of the resonance frequency in the decreasing direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of adjusting the resonance frequency of a dielectric filter, and more particularly to a method of adjusting the resonance frequency of a dielectric filter according to the distance between its terminal electrode and an outer conductor.

[0002]

2. Description of the Related Art Various dielectric filters are used in a high frequency range from the UHF band to the microwave band. Among them, a dielectric filter is often used which is a combination of a TEM resonator having a through hole, an inner conductor formed in the through hole, and an outer conductor formed on the outer peripheral surface. There are a structure in which individual resonators are connected and a structure in which a plurality of resonance records are integrated in a block.

In these dielectric filters, input / output coupling capacitance must be formed between the inner conductor of the resonator at the input / output stage. This coupling capacitance can be measured by connecting a capacitor or by using a dielectric substrate on which a capacitor is formed, by inserting a metal rod coated with a dielectric into a through hole where an inner conductor is formed, or by using a dielectric near the inner conductor. Various methods have been considered, such as inserting a metal rod into a hole provided in the body or forming a metal film on the outer peripheral surface separately from the outer conductor.

In the field of dielectric filters, there is a demand for miniaturization and thinning, and the wavelength must be shortened as the frequency band rises, so that the dimensions must be shortened. Therefore,
The present inventor previously proposed in Japanese Patent Application No. 4-179112 a structure in which two dielectric substrates are bonded to each other to form a dielectric filter, and an input / output electrode is formed on the bonding surface.

[0005]

When it is necessary to widen the required bandwidth in the dielectric filter, the value of the input / output coupling capacitance must be increased. However, if the filter is downsized, the size of the electrode forming the coupling capacitance is also restricted, and it becomes difficult to obtain a large capacitance. Also, Q
The problem of decrease in

It is also desirable to avoid adding or connecting special parts in order to obtain a large input / output coupling capacity. Further, a structure capable of finely adjusting the resonance frequency is desirable.

The present invention solves the above problems and adjusts the resonance frequency suitable for a dielectric filter for connecting a dielectric resonator at an input / output terminal to an external circuit with a simple structure and manufacturing process. It provides a method.

[0008]

According to the present invention, a conductor film connected to an inner conductor of a resonator at an input / output end of a dielectric block is connected to a terminal electrode at an impedance matching point, and the terminal electrode and the outer conductor are connected to each other. The above problem is solved by adjusting the distance.

That is, a flat second dielectric substrate is adhered on the grooved surface of a first dielectric substrate having a plurality of linearly extending parallel concave grooves, and the second dielectric substrate is bonded to the inside of the concave groove and the second dielectric substrate. The inner conductor is formed on the surface of the dielectric substrate facing the groove, and the outer conductor is formed on the unbonded surface of the first and second dielectric substrates and the end surface parallel to the extending direction of the groove. In a resonance frequency adjusting method for a dielectric filter, in which a short-circuit conductor is formed on one of the exposed end surfaces of the groove to form a plurality of resonators, the groove extends at least on the adhesive surface of the dielectric substrate. It is formed by extending from the end face parallel to the direction to the groove direction that becomes the input / output resonator, connected to the inner conductor at the impedance matching point, and insulated from the outer conductor on the end face parallel to the extending direction of the groove. Connected to the terminal conductor film, and Those having features to adjust a resonant frequency by adjusting the distance between the conductors.

[0010]

Function: The resonance frequency is lowered by increasing the distance from the terminal electrode. Fine tuning of the resonance frequency is possible even after assembly and mounting.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a state before assembly of a dielectric filter to which the present invention is applied. A flat second dielectric substrate (12) is adhered to the side of the first dielectric substrate (11) having two parallel concave grooves (14) with the concave groove (14) with glass or the like.
This forms a block of dielectric with two parallel through holes. In the present invention, the dielectric substrate 12
The conductor pattern 16 is formed in advance on the bonding surface of.
The conductor pattern 16 is formed so as to extend from an end surface parallel to the extending direction of the concave groove 14 to a portion facing the concave groove, and after adhesion, the concave groove 14 of the dielectric substrate 11 and the dielectric substrate facing it.
It is formed so as to be connected to the inner conductor formed on the surface of 12.

FIG. 2 shows that after the bonding and the formation of the conductor film,
It is a perspective view which shows the same dielectric filter as FIG. It has a structure in which two through holes 25 are formed in a dielectric block formed by adhering the dielectric substrate 21 and the dielectric substrate 22. An inner conductor is formed on the surface of the through hole 25, and the through hole 25
An outer conductor 27 is formed on the outer peripheral surface parallel to the extending direction of the. FIG. 2 shows an example of two elements of the interdigital type. The front side of the resonator on the left side is an open end surface, and the front side of the resonator on the right side is a short circuit end surface. A body filter is constructed.

The conductor pattern (16) formed on the joint surface shown in FIG. 1 is connected to the terminal electrode 28 at the end surface of the dielectric substrate, and the inner conductor formed by the conductor film formed in the through hole 25 and the terminal electrode 28. Connect directly. The conductor pattern (16) is connected to the inner conductor at an impedance matching point such as the 50 ohm point of the inner conductor of the resonator at the input / output end. As a result, the input / output terminal is directly connected to the inner conductor of the resonator at the input / output end in a state of impedance matching.

The terminal electrode 28 is a conductor film formed across two dielectric substrates, and is formed close to the outer conductor 27 although it is insulated from the outer conductor 27. Therefore, a capacitance is formed between the input / output terminal and the ground. Terminal electrode
Trimming either of the facing portions of the outer conductor 27 and the outer conductor 27 changes the magnetic field distribution and changes the resonance frequency. When the space is widened, the resonance frequency changes in the direction of lowering. By this trimming, the frequency change (Δf /
f ₀ ) can be changed by about 1%.

In the above example, the interdigital type two-element dielectric filter is shown, but a block of three or more elements can also be used, and a combline type dielectric filter in which the open end face and the short-circuited end face are aligned. The same applies to body filters.

[0017]

According to the present invention, not only is the input / output coupling capacitance unnecessary and a small dielectric filter can be obtained, but
The resonance frequency can be easily adjusted.

As a result, a dielectric filter requiring a wide pass band can be obtained in a small size and at a low cost.

[Brief description of drawings]

FIG. 1 is a dielectric filter to which the present invention is applied (before assembly).
Perspective view showing

FIG. 2 is a dielectric filter to which the present invention is applied (after assembly)
Perspective view showing

[Explanation of symbols]

 11, 21: (First) dielectric substrate 12, 22: (Second) dielectric substrate 16: Conductor pattern 27: Outer conductor 28: Terminal electrode

[Procedure amendment]

[Submission date] August 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0012]

2. Description of the Related Art Various dielectric filters are used in a high frequency range from the UHF band to the microwave band. Among them, a dielectric filter is often used which is a combination of a TEM resonator having a through hole, an inner conductor formed in the through hole, and an outer conductor formed on the outer peripheral surface. There are a structure in which individual resonators are connected and a structure in which a plurality of resonators are integrated in a block.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 18, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Various dielectric filters are used in a high frequency range from the UHF band to the microwave band. Among them, a dielectric filter is often used which is a combination of a TEM resonator having a through hole, an inner conductor formed in the through hole, and an outer conductor formed on the outer peripheral surface. There are a structure in which separate resonators are connected and a structure in which a plurality of resonators are integrated in a block.

Claims (2)

[Claims] 1. A flat second dielectric substrate is adhered onto the grooved surface of a first dielectric substrate having a plurality of parallel grooves extending linearly, and a flat second dielectric substrate is adhered to the inside of the groove and the second dielectric substrate. The inner conductor is formed on the surface of the dielectric substrate facing the groove, and the outer conductor is formed on the unbonded surface of the first and second dielectric substrates and the end surface parallel to the extending direction of the groove. In a resonance frequency adjusting method for a dielectric filter, in which a short-circuit conductor is formed on one of the exposed end surfaces of the groove to form a plurality of resonators, the groove extends at least on the adhesive surface of the dielectric substrate. It is formed by extending from the end face parallel to the direction to the groove direction that becomes the input / output resonator, connected to the inner conductor at the impedance matching point, and insulated from the outer conductor on the end face parallel to the extending direction of the groove. Connected to the terminal conductor film and the terminal conductor film and the outer conductor A resonance frequency adjusting method for a dielectric filter, comprising adjusting a resonance frequency by adjusting a distance. 2. A flat second dielectric substrate is adhered onto the grooved surface of a first dielectric substrate having a plurality of parallel grooves extending linearly, and a flat second dielectric substrate is adhered to the inside of the groove and the second dielectric substrate. The inner conductor is formed on the surface of the dielectric substrate facing the groove, and the outer conductor is formed on the unbonded surface of the first and second dielectric substrates and the end surface parallel to the extending direction of the groove. In a resonance frequency adjusting method for a dielectric filter, in which a short-circuit conductor is formed on one of the exposed end surfaces of the groove to form a plurality of resonators, the groove extends at least on the adhesive surface of the dielectric substrate. It is formed by extending from the end face parallel to the direction to the groove direction that becomes the input / output resonator, connected to the inner conductor at the impedance matching point, and insulated from the outer conductor on the end face parallel to the extending direction of the groove. Connected to the terminal conductor film and the terminal conductor film and the outer conductor A resonance frequency adjusting method for a dielectric filter, characterized in that the resonance frequency is lowered by increasing the distance.