JP2000114808A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a terminal electrode at a position away from a shunt conductor. SOLUTION: When connecting a conductor pattern 16 to be pulled out of an impedance matching point to the terminal electrode on an end face 19 and a terminal, a conductor pattern 18 is pulled out of the position of high impedance to the end face 19 and connected to the terminal electrode. At the same time, the conductor pattern 16 to be connected from the intermediate part of that conductor pattern 16 to the shunt electrode is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a dielectric filter, and more particularly to a structure of a conductor pattern for obtaining a connection between a resonator at an input / output end and a terminal electrode. .

[0002]

2. Description of the Related Art Various dielectric filters are used in a high frequency range such as a UHF band to a microwave band. Among them, a dielectric filter including a TEM resonator in which an inner conductor is formed in a portion having a through hole and an outer conductor is formed on an outer peripheral surface thereof is often used. There are a type that is configured by connecting individual resonators, and a type that is integrated with a dielectric block.

In these dielectric filters, input and output coupling capacitances must be formed between the input and output stages and the inner conductor of the resonator. As a means to obtain this coupling capacity,
There are methods for connecting a capacitor and using a dielectric substrate on which the capacitor is formed. In addition, a metal rod coated with a dielectric may be inserted into the through-hole in which the inner conductor is formed, a metal rod may be inserted into a hole provided in the dielectric near the inner conductor, or the outer conductor may be separated from the outer conductor. Or a method of forming a metal film.

In the field of dielectric filters, there is a demand for miniaturization and thinning, and the size must be reduced because the wavelength becomes shorter as the frequency band increases. Accompanying this, it is also difficult to obtain input / output coupling capacitance. Therefore, Japanese Patent Application Laid-Open No. 6-125204 discloses a dielectric filter in which two dielectric substrates are bonded, a conductive pattern is formed on the bonded surface, and the input / output conductive pattern is directly connected to the impedance matching point. Proposed.

FIG. 2 is an exploded perspective view of an example of the dielectric filter before assembly. A flat plate-shaped second dielectric substrate 22 is bonded with glass or the like to the surface of the first dielectric substrate 21 having the two parallel concave grooves 24 on which the concave grooves 24 are provided. As a result, a dielectric block having two parallel through holes is formed. A conductor pattern 26 is formed on the bonding surface of the dielectric substrate 22 in advance, and the conductor pattern 26 is formed so as to extend from an end surface parallel to the extending direction of the groove to a portion facing the groove, After bonding, it is connected to the inner conductor.

FIG. 3 is a perspective view showing a dielectric filter having a conductor film formed after bonding. Dielectric substrate 21 and dielectric substrate
The structure is such that a through-hole 25 is formed in a dielectric block to which the substrate 22 is bonded. An inner conductor is formed in the through hole 25, and an outer conductor 27 is formed on an outer peripheral surface parallel to a direction in which the through hole 25 extends. Terminal electrode 28 surrounded by outer conductor
Is formed, and the conductor pattern 26 shown in FIG. 2 is connected.

[0007]

As described above, in a type in which input and output are directly obtained at an impedance matching point, and when an attempt is made to obtain a dielectric filter having a narrow band in a high frequency band, the impedance matching point is very close to the short-circuit end face. Get closer.

[0008] Since the conductor pattern drawn from the impedance matching point to the end face is connected to the terminal electrode, in that case, the terminal electrode may cover the short-circuit end face, making it difficult to form the terminal electrode. The terminal electrode is preferably formed on the end face of the dielectric block so as to be surrounded by an outer conductor in terms of maintaining characteristics. The present invention provides a dielectric filter capable of forming a terminal electrode at a position away from a short-circuit end face.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem by improving the input / output conductor pattern.

That is, in a dielectric filter in which a plurality of resonators are integrally formed by bonding two dielectric substrates, a first dielectric substrate having a plurality of linear grooves extending linearly. An inner conductor is formed on a surface in the through hole of a dielectric block in which a plurality of through holes are formed by bonding a flat second dielectric substrate on a surface having a concave groove, and the first dielectric Outer conductors are formed on the respective surfaces of the substrate and the second dielectric substrate facing the bonding surface, and on both end surfaces parallel to the direction in which the concave groove extends, and a short-circuit conductor is formed on one of the open end surfaces of the through hole. A plurality of resonators are integrally formed in the dielectric block, and at least one of the dielectric substrates has an adhesive surface extending from an end surface parallel to the extending direction of the groove in the direction of the groove serving as an input / output resonator. Connected to conductors and insulated and separated from outer conductors at both ends It is connected to the child electrodes, and it has the characteristics that equipped with conductor pattern connected to the short-circuit conductor extending from their middle portions to short-circuit conductor.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A conductor pattern extending from a conductor pattern connecting a terminal electrode to a point closer to an open end face from an impedance matching point of a resonator at both ends to a short-circuit end face is added. Is made to be 50Ω, and the input and output impedances are matched.

[0012]

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

FIG. 1 is an exploded perspective view of an example of the dielectric filter before assembly. A flat plate-shaped second dielectric substrate 12 is bonded to a surface of the first dielectric substrate 11 having the two parallel concave grooves 14 with the concave grooves 14 by using glass or the like. As a result, a dielectric block having two parallel through holes is formed. A conductor pattern 16 is formed on the bonding surface of the dielectric substrate 12 in advance, and the conductor pattern 16 extends linearly from an end surface parallel to the direction in which the groove extends to a portion facing the groove, and And a conductor pattern 18 branched in a right angle direction, and the conductor pattern 18 is drawn out to an end face 19 which becomes a short-circuit end face after assembly.

After the two dielectric substrates 11 and 12 are bonded together, an inner conductor, an outer conductor, and a terminal electrode are formed in the same manner as shown in FIG.

The conductor pattern 16 is connected to the inner conductor on the open end face side of the original impedance matching point of 50Ω. The conductor pattern 28 is connected to the ground potential from an intermediate portion of the conductor pattern 26, and the impedance formed by the conductor pattern 28 is added in parallel.

The present invention is applied to a 5.2 mm × 5.7 mm × 2.0 mm 2500 MHz
When applied to a band dielectric filter, it was possible to move an input / output conductor pattern, which had to be connected at 0.3 mm from the short-circuit end face, to the open end face by 0.5 mm.

[0017]

According to the present invention, the input / output electrodes can be moved toward the open end face, the terminal electrodes can be formed so as not to cover the short-circuit end face, and a dielectric filter having good characteristics can be obtained. . The shape of the terminal electrode is not restricted, and a dielectric filter with a high degree of design freedom can be realized.

Further, since it can be realized only by changing the shape of the conductor pattern, a small and inexpensive dielectric filter can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a conventional dielectric filter.

FIG. 3 is a perspective view of a conventional dielectric filter.

[Explanation of symbols]

 11, 12, 21, 22: Dielectric substrate 14, 24: Groove 16, 26: Conductor pattern 18: Conductor pattern

Claims (2)

[Claims] 1. A dielectric filter in which a plurality of resonators are integrally formed by bonding two dielectric substrates to each other, wherein the first dielectric substrate includes a plurality of parallel concave grooves extending linearly. An inner conductor is formed on a surface in the through hole of a dielectric block in which a plurality of through holes are formed by bonding a flat second dielectric substrate on a surface having a concave groove, and the first dielectric Outer conductors are formed on the respective surfaces of the substrate and the second dielectric substrate facing the bonding surface, and on both end surfaces parallel to the direction in which the concave groove extends, and a short-circuit conductor is formed on one of the open end surfaces of the through hole. A plurality of resonators are integrally formed in the dielectric block,
At least one of the dielectric substrates has an adhesive surface extending from an end surface parallel to the extending direction of the concave groove in the concave groove direction serving as an input / output resonator and connected to the inner conductor, and is insulated and separated from the outer conductor at both end surfaces. A dielectric pattern comprising a conductor pattern connected to the terminal electrodes and extending from an intermediate portion thereof to the short-circuit conductor and connected to the short-circuit conductor. 2. The dielectric filter according to claim 1, wherein the conductive pattern is formed on a flat dielectric substrate.