JPH0260302A - Dielectric filter and method for adjusting its resonance frequency - Google Patents

Abstract

PURPOSE:To easily adjust a resonator unit to a desired frequency and to facilitate assembling and adjusting by inserting a means to couple in a capacity way with an inner conductor to three through holes and connecting the conductor of an intermediate means to a ground potential. CONSTITUTION:Into a through hole 11 of the resonator unit at both ends, dielectric unit 14a is inserted in order to obtain the coupling capacity of an input output. A dielectric unit 14b of the same construction as a unit 14a is inserted into the through hole 11 of the central resonator unit, the length of the metallic pin is adjusted and the capacity is adjusted. Three units share a flange 16, and for the unit 14b, the length of the pin protruded to the Iower side of the flange 16 may be shorter. Units 14a and 14b are inserted from the releasing edge side of the lower surface of the dielectric block 10 of the through hole 11 and the bottom surface and the side surface of the block 10 are covered with an earth potential shield plate 19. For the units 14a and 14b, by the shield plate 19, the flange 16 is abutted to the block 10 and the insertion dimension of the dielectric unit is kept constant. Consequently, the adjustment of the resonance frequency can be performed by the insertion of the dielectric unit and the adjusting manhour is also reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a block-shaped dielectric filter equipped with two or more resonator units, and particularly to a method for adjusting the resonant frequency of an intermediate resonator unit. The present invention relates to a structure and a method for doing so.

[Prior art]

Block-type dielectric filters, in which a plurality of resonator units are integrally formed in one dielectric block, are used in various fields in the microwave region. Resonator Uniso 1
Some have two - and others have three or more.

In a dielectric filter having three or more resonator units, the resonance frequencies of each stage are not the same. To adjust this,
As shown in FIG. 3, there is a method of changing the dimension 1 from the open end surface to the shorted end surface of the resonator unit. This length of the intermediate resonator unit is increased by 1'' in order to lower the resonant frequency determined by this length.

However, this method has the problem that the open end face needs to be polished in different steps, requiring a large number of man-hours for processing.

Alternatively, as shown in FIG. 4, there is a method in which a conductor pattern 47 that is electrically connected to the inner conductor of the intermediate resonator unit is formed on the open end surface, and the conductor pattern 47 and the outer conductor 45 are closely opposed to each other. As a result, a capacitance is formed between the conductive pattern 45 and the outer conductor 45 at the ground potential.

However, it is necessary to form and adjust the conductor pattern minutely, and great care is required.

〔assignment〕

The present invention aims to solve the above problems and easily adjust a resonator unit to a desired frequency.

It is also an attempt to obtain a dielectric filter that is easy to assemble and adjust.

[Means to solve the problem]

The present invention solves the above problem by inserting a dielectric unit into the intermediate resonator unit and thereby forming a capacitance between the inner conductor and the ground.

That is, in a dielectric filter having through holes formed with three or more conductor films at predetermined intervals in a dielectric filter, the means for capacitively coupling with the inner conductor of the through holes at both ends is the through hole at both ends. It is characterized in that a means is inserted into the hole and capacitively coupled with the inner conductor of the intermediate through hole, and the conductor of the means inserted into the intermediate through hole is connected to a ground potential. It is something.

This is realized by a structure in which a dielectric unit is used as a capacitive coupling means and its conductor is connected to a shield plate that is at ground potential.

In other words, a dielectric filter resonant frequency adjustment method and method for lowering the resonant frequency of an intermediate resonator of a dielectric filter having through holes in which three or more conductive films are formed at predetermined intervals in a dielectric block. By inserting dielectric units into the through holes at both ends to obtain input/output coupling capacity, and by inserting a dielectric unit into the intermediate through hole and connecting the conductor of the dielectric unit to the ground potential, The feature is that a capacitance is formed between the inner conductor formed in the intermediate through hole and the ground potential, thereby lowering the resonant frequency of the intermediate resonator unit.

〔Example〕

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

FIG. 1 is an exploded perspective view showing an embodiment of the present invention. Three through holes 11 are formed in the dielectric block 10, and a conductor film is formed in each of the through holes 11 to serve as an inner conductor. A conductive film is also formed on the side surface of the dielectric block 10 to serve as an external conductor. A conductive film is also formed on the upper surface of the dielectric pro-2 10, forming a short-circuited end surface, but no conductive film is formed on the lower surface, resulting in an open end surface. Note that a coupling hole 13 is formed to adjust the coupling between the resonator units IHI and C, and no conductor film is formed in this coupling hole 13.

Dielectric units 14a are inserted into the through holes of the resonator units at both ends in order to obtain input/output coupling capacitance. The dielectric unit 44a is a metal pin such as copper coated with a dielectric material such as polyethylene, and is provided with a collar 16 to maintain the insertion length. A capacitance is formed between the metal pin and the inner conductor.

Dielectric material 1-node 14 is also connected to the through hole of the central resonator unit.
b is inserted. This dielectric unit 14b has the same structure as the input/output dielectric Uniso I 14a,
Capacity is adjusted by adjusting the length of the metal pin inserted into the through hole. It is the same that the bottle 16 has the flange 16, but the length of the bottle that projects downward may be short.

Insert the dielectric UniSolo 4a and 14b into the through hole 1 of the dielectric block 10 from the open end side, and then seal 1).
and 19 to cover the bottom and side surfaces of the dielectric flock 10. By this shield plate 19, dielectric unit/1i4a, 14
h is supported with the collar 16 in contact with the dielectric block 10. Since the shield plate 19 is at ground potential, it is possible to connect the outer conductor of the resonator unit to the side surface of the dielectric block 10 and the solder side.

FIG. 2 is a front cross-sectional view showing the 3rd position.

The dielectric block 10 includes dielectric units H4a and 14b.
is inserted. The collar 16 of the dielectric unit is held between the seals 1-1 and 19, and the dimensions of the dielectric unit inserted are kept constant. The dimensions of the metal pin protruding toward the flange 1G side can be set arbitrarily, but it must be long enough to be inserted into the printed circuit board at the input/output stage.

However, in the intermediate stage, the tips of the metal pins may be soldered to the shield plate 16, so it is sufficient that they protrude slightly.

The dielectric unit 1- is made with different lengths, and the dielectric unit 1- is made to have a predetermined capacitance depending on the characteristics of each element.
It is best to select the throat and insert it. Further, the length may be adjusted by grinding or the like to obtain a desired capacity.

〔effect〕

According to the present invention, the resonant frequency can be adjusted using a dielectric corniso I.
・This can be done by simply inserting the , and the number of T for adjustment can be significantly reduced.

In addition, it is easy to reorganize, and since it is sufficient to use the same structure as that for input/output, it is advantageous in terms of reducing the number of parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of an embodiment of the present invention, FIG. 2 is a front sectional view thereof, and FIGS. 3 and 4 are perspective views of a conventional dielectric filter. 11...Dielectric block 14...Dielectric unit 19...
...shield plate

Claims (6)

[Claims] (1) In a dielectric filter having through-holes in which three or more conductive films are formed at predetermined intervals in a dielectric block,
Means for capacitively coupling with the inner conductors of the through holes at both ends are inserted into the through holes at both ends, and means for capacitively coupling with the inner conductors of the through holes at both ends are inserted into the intermediate through hole. A dielectric filter characterized in that the conductor of the inserted means is connected to ground potential. (2) The dielectric filter according to claim 1, wherein the capacitively coupling means is a dielectric unit in which a conductor is coated with a dielectric. (3) In a dielectric filter having through holes formed with three or more conductive films at predetermined intervals in a dielectric block,
Dielectric units are inserted into the through holes at both ends to obtain input/output coupling capacitance, and a dielectric unit is also inserted into the intermediate through hole, and the dielectric unit is placed close to the open end surface of the dielectric block. The conductor of the dielectric unit inserted into the intermediate through hole is electrically connected to the shield plate, and a capacitance is formed between the inner conductor formed in the intermediate through hole and the ground potential. A dielectric filter characterized by: (4) The dielectric filter according to claim 3, wherein the conductor of the dielectric unit inserted into the intermediate through hole is soldered to the shield plate. (5) A dielectric filter resonant frequency adjustment method for lowering the resonant frequency of an intermediate resonator of a dielectric filter having through holes in which three or more conductive films are formed at predetermined intervals in a dielectric block, By inserting dielectric units into the through holes at both ends to obtain input/output coupling capacitance, and by inserting a dielectric unit into the intermediate through hole and connecting the conductor of the dielectric unit to the ground potential, the intermediate A method for adjusting the resonant frequency of a dielectric filter, characterized in that a capacitance is formed between an inner conductor formed in a through hole and a ground potential, thereby lowering the resonant frequency of an intermediate resonator unit. (6) The method for adjusting the resonant frequency of a dielectric filter according to claim 5, wherein the resonant frequency of the intermediate resonator unit is changed by changing the length of insertion of the dielectric unit.