JPH0633687Y2 - Dielectric block for constructing a dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a dielectric block used to construct a distributed constant dielectric filter.

[Prior Art] Distributed constant type dielectric filters for bandpass filters in the several hundred MHz to several GHz band for use in car phones and the like are already known. This type of dielectric filter has a plurality of through holes for resonance extending from one end surface to the other end surface of the dielectric block, an inner conductor layer on the inner peripheral surface of each through hole, and an outer conductor layer on the outer peripheral surface. And a coupling hole for mutual inductive coupling between the resonance through holes.

[Problems to be solved by the device]

By the way, the shape of the coupling hole affects the electrical characteristics such as the pass band width, the attenuation characteristic, and the insertion loss of the band pass filter.
Therefore, when various dielectric filters having different characteristics are required, it is necessary to prepare various dielectric blocks having different shapes of coupling holes. Since the dielectric block is molded using a mold, multiple types of expensive molds must be prepared to form multiple types of dielectric blocks, and the unit price of the dielectric filter is inevitable. It became high.

Therefore, an object of the present invention is to provide a dielectric block that can reduce the cost of the dielectric filter.

[Means for Solving the Problems] The present invention for achieving the above object is formed into a prismatic shape having a pair of end faces and a plurality of side faces facing each other, and a through hole extending from one of the pair of end faces to the other. The present invention relates to a dielectric block for forming a dielectric filter in which at least two side surfaces are provided with recesses of different shapes. In addition, the said recessed part of a different form means the recessed part where at least one of a shape, a dimension, and a position differs.

[Function] The dielectric block according to the present invention functions as a dielectric for forming one resonator included in the dielectric filter. Therefore, when constructing a dielectric filter including a plurality of resonators, it is necessary to bond a plurality of dielectric blocks of the present invention. The recess formed on the side surface of the dielectric block serves as a coupling hole or a coupling recess for mutually inductively coupling the resonators. Since one dielectric block has concave portions having different forms (at least one of shape, size, and position) on a plurality of side surfaces, it is possible to obtain a plurality of dielectric filters having different characteristics depending on how the concave portions are combined. When constructing a multi-stage dielectric filter including three or more resonators, dielectric blocks of the same formation may be joined in multiple stages, or the same dielectric block may be used for the input stage and the output stage. Alternatively, a dielectric block having another shape may be arranged in the intermediate stage.

[First Embodiment] Next, a dielectric block of a first embodiment and a distributed constant type dielectric filter using the same will be described with reference to FIGS. 1 to 7.

When constructing a dielectric filter, first, a plurality of dielectric blocks 1 made of, for example, barium titanate-based ceramics shown in FIG. 1 are prepared. This dielectric block 1 is formed into a quadrangular prism shape by a mold so as to have a pair of end faces 2 and 3 and first, second, third and fourth side faces 4, 5, 6 and 7, and is fired. Which has a through hole 8 extending from one end face 2 to the other end face 3 and has four side surfaces having different first, second, third and fourth recesses 9, 10,
Have 11 and 12. The through hole 8 is used for forming a resonator,
The recesses 9, 10, 11, 12 are used to form the coupling holes.

Next, when the first concave portion 9 is used for coupling among the four concave portions 9 to 12, the second and second portions except the first side surface 4 having the first concave portion 9 as shown in FIG. 3 and the fourth side surface 5,
Conductor layers are provided on the lower end face 3 and the through holes 6 and 7 by dipping or plating. That is, as shown in FIG. 2, the inner conductor layer 13 is provided in the through hole 8, the outer conductor layer 14 is provided on the three side faces 5, 6, 7, and the end face conductor layer 15 is provided at the end face 3. In addition,
The outer conductor layer 14 is also provided in the recesses 10, 11, 12.

Next, the two dielectric blocks 1a and 1b are bonded with an adhesive (not shown) as shown in FIG. 3 so that the first side surface 4 having the first recess 9 becomes a bonding surface. That is, two dielectric blocks 1a having the same structure as the dielectric block 1 of FIG.
1b is prepared, and the first side surfaces 4 of the two dielectric blocks 1a and 1b are adhered to each other so that the coupling holes 9a are formed by the two recesses 9. In addition, before or after joining the two dielectric blocks 1a and 1b, as shown in FIG. 4, a terminal unit 18 in which a terminal pin 16 and a tubular dielectric 17 are integrated is provided in each of the two through holes 8. Get in. As a result, the dielectric filter shown in the equivalent circuit of FIG. 5 is obtained. That is, the first resonator is obtained from the capacitor C1 and the inductance L1 of FIG. 5 based on the one through hole 8, and the second resonator including the capacitor C2 and the inductance L2 is obtained based on the other through hole 8.
, And both resonators have inductive impedance Z
Are connected to each other by. The coupling capacitors Ca and Cb are obtained based on the terminal pin 16 and the inner conductor layer 13 in each through hole 8. In addition, the resonator in each through hole 8
It is configured as a 1/4 wavelength distributed constant type coaxial resonator.

When constructing dielectric filters having different characteristics, the same dielectric block 1 as that shown in FIG. 1 is used, but the first concave portion 9 is used.
The coupling hole is formed based on the concave portion different from the above. For example, the fourth side face 7 having the fourth recess 12 is joined together to form the dielectric filter shown in FIG. Alternatively, the third side face 6 having the third recess 11 is joined to each other to form the dielectric filter shown in FIG.

Since the coupling hole 12a in FIG. 6 and the coupling hole 11a in FIG. 7 have different shapes from the coupling hole 9a in FIG. 3, there are differences in the pass band width, attenuation characteristic, insertion loss, etc. of the bandpass filter.

Since the second recess 10 can also form a coupling hole, it is possible to provide a dielectric filter having various characteristics based on the one type of dielectric block 1 shown in FIG.

[Second Embodiment] Next, a dielectric block of a second embodiment and a dielectric filter using the same will be described with reference to FIGS. 8 to 10.
However, the reference numerals 1 to 18 in FIGS. 8 to 10 and FIGS. 11 to 14 to be described later are substantially the same as those denoted by the same reference numerals in FIGS. 1 to 7. Since they are present, their description will be omitted.

First and third side faces 4, 6 of the dielectric block 1 of FIG.
The first and third recesses 9 of the same have the same shape, and the second and fourth recesses 10 and 12 of the second and fourth side faces 5 and 7 also have the same shape. It is of course possible to use the dielectric block 1 of FIG. 8 to form a dielectric filter including two resonators as shown in FIG. 3, but the dielectric block 1 of FIG.
Is suitable for a three-stage dielectric filter or a multi-stage dielectric filter having a larger number of stages as shown in FIGS. When constructing the dielectric filter shown in FIG. 9, three dielectric blocks 1 shown in FIG. 8 are prepared, and the third side face 6 of the first-stage dielectric block 1a and the second-stage dielectric block 1b are prepared. The first side face 4 of the second stage is joined to the third side face 6 of the second-stage dielectric block 1b and the third stage dielectric block 1c.
And the first side face 4 of the. As a result, coupling holes 21 and 22 composed of a combination of the first concave portion 9 and the third concave portion 11 are obtained between the three resonance through holes 8. The terminal unit 18 including the terminal pin 16 and the dielectric 17 is fitted only in the through hole 8 of the first and third dielectric blocks 1a and 1c.

FIG. 10 shows a three-stage dielectric filter having characteristics different from those in FIG. Here, the second side face 5 of the first-stage dielectric block 1a and the fourth side face 7 of the second-stage dielectric block 1b are fitted together, and the second side face of the second-stage dielectric block 1b is fitted. The side surface 5 and the fourth side surface 7 of the third-stage dielectric block 1c are joined together. Therefore, coupling holes 23 and 24 are obtained between the three resonance through holes 8 by combining the second recess 10 and the fourth recess 12.

[Modification] The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(1) As shown in FIG. 11, concave portions 25 having different shapes may be provided on each side surface of the octagonal dielectric block 1. Further, the dielectric block 1 can be formed into various polygonal prisms such as a triangular prism or more.

(2) As shown in FIG. 12, the recesses 9, 10, 11, 12 may be formed halfway from one end face 2 of the dielectric block 1 to the other end face 3.

(3) A plurality of recesses 9 may be provided on the side surface 4 of the dielectric block 1 as shown in FIG. Further, the recess 10 may be provided in the horizontal direction as shown in the side surface 5 of FIG. In short, the recess for coupling may be provided so that at least one of shape, size and position is different.

(4) As shown in FIG. 14, recesses 10, 11 and 12 are provided in the center of the side surfaces of the dielectric blocks 1a and 1b in a non-coincident manner, and the third recess 11 of the two dielectric blocks 1a and 1b is provided. The side surfaces 6 may be joined to each other so that two coupling holes 11a are formed.

(5) It is also applicable to the case where the end face conductor layer 15 is omitted and a dielectric filter including a 1/2 wavelength distributed constant type resonator is formed.

(6) In the embodiment, after forming the inner conductor layer 13, the outer conductor layer 14, and the end face conductor layer 15 as shown in FIG. 2, the plurality of dielectric blocks 1 are joined to each other. The conductor layers 13, 14, 15 may be provided after joining. Further, the dielectric block 1 may be welded without being adhered.

(7) An input or output terminal may be coupled to the inner conductor layer 13 without a coupling capacitor, and a coupling capacitor may be separately provided. Further, instead of obtaining the coupling capacitor by the dielectric 17, an individual capacitor having a terminal pin is arranged in the through hole 8, and one electrode of this capacitor is connected to the inner conductor layer.
May be connected to 13.

[Advantages of the Invention] As is clear from the above, one dielectric block can be used for a plurality of types of dielectric filters having different characteristics or different numbers of stages. Therefore, the cost of the dielectric filter can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dielectric block of a first embodiment of the present invention, FIG. 2 is a perspective view showing the dielectric block of FIG. 1 with a conductor layer, and FIG. The top view which shows the state which joined the two dielectric blocks of the same structure as FIG. 4, FIG. 4 is a partially cutaway perspective view which shows the completed dielectric filter, FIG. 5 is the equivalent of the dielectric filter of FIG. Circuit diagrams, FIGS. 6 and 7 are plan views showing dielectric filters having different characteristics formed based on the dielectric block of FIG. 1, and FIG. 8 is a dielectric of the second embodiment of the present invention. 9 is a plan view showing a body block, FIGS. 9 and 10 are plan views showing dielectric filters having different characteristics formed based on the dielectric block shown in FIG. 8, and FIG. 11 is a dielectric of a modification of the present invention. 12 and 13 are perspective views showing the body filter without terminals, and FIG. Perspective view showing a modification of FIG. 14 is a plan view showing a dielectric filter of a modification. 1 ... Dielectric block 2, 3 ... End face, 4, 5, 6, 7 ...
Sides, 8 ... Through holes, 9, 10, 11, 12 ... Recesses, 13 ... Inner conductor layer, 14 ... Outer conductor layer.

Claims (1)

[Scope of utility model registration request] 1. A prismatic shape having a pair of end surfaces and a plurality of side surfaces facing each other, a through hole extending from one of the pair of end surfaces to the other is provided, and at least two of the side surfaces have different shapes. A dielectric block for constructing a dielectric filter, characterized in that a recess is provided.