JPH0591003U - Dielectric filter - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the number of parts of the dielectric filter and simplify the structure. [Structure] The dielectric filter 1 is composed of a dielectric coaxial resonator 2 in which three coaxial resonators are integrally molded, and a coupling substrate 7. A recess 5 is formed in the open end face 31 of the dielectric coaxial resonator 2 at the position where the hole 4 is formed, and the electrode D is formed at the bottom of the recess 5.
1'-D3 'are formed. Electrodes D1 to D3 are formed at predetermined positions on the substrate surface 71 of the combined substrate 7.
When the coupling substrate 7 is attached to the open end face 31 of the dielectric coaxial resonator 2, the electrodes D1 to D3 are provided at a predetermined interval and the electrode D
Electrodes D1 to D3 and D1 'are arranged to face 1'to D3'.
To D3 'by the capacitance formed between the dielectric coaxial resonator 2
And the coupling substrate 7 are coupled to complete the dielectric filter 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dielectric filter structure in which a plurality of dielectric coaxial resonators are connected in series.

[0002]

[Prior Art]

 FIG. 13 is a main part perspective view showing an example of the structure of a conventional band elimination filter (hereinafter referred to as BEF) using a dielectric coaxial resonator. The case and cover are omitted in FIG. Also, it shows that the stippled area is covered with a conductive member.

The BEF shown in FIG. 1 is a three-stage dielectric filter using, for example, 2.5 mm square prismatic dielectric coaxial resonators R1 to R3. Electrodes d1 to d3 are formed on the surface of the coupling substrate 20 facing the central conductors M1 to M3 of the dielectric coaxial resonators R1 to R3, respectively, between the electrodes d1 and d2 and between the electrodes d2 and d3. Are connected by coils L1 and L2 each formed of an air-core coil.

A ground electrode (not shown) is formed on the back surface of the combined substrate 20, and a capacitor is formed between the ground electrode and the electrodes d1 to d3 on the surface. Also, individual capacitors 21, 22, and 23 are attached to the electrodes d1 to d3 on the surface of the substrate, and these capacitors 21 to 23 are dielectric coaxial resonators R1 to R3 via coupling terminals T1, T2, and T3. Of the central conductors M1 to M3.

FIG. 14 is a perspective view of an essential part showing an example of the structure of a conventional bandpass filter (hereinafter referred to as BPF) using a dielectric coaxial resonator. Note that the case and cover are omitted in FIG.

The BPF shown in the figure is a three-stage dielectric filter. The three dielectric coaxial resonators are integrally molded by the resonator 24. The stippled portion of the resonator 24 is shown to be covered with a conductive member. Coupling pins P1 and P3 are coaxially attached to holes 25 and 27 forming the central conductor of the dielectric coaxial resonator via fitting members 28 and 30 made of resin, and are connected to the coupling pins P1 and P3. A coupling capacitance is formed between the central conductors (conductors applied to the inner peripheral surfaces of the holes 25 and 27). A metal case 31 is attached to the tips of the coupling pins P1 and P3 to shield the open end face of the dielectric coaxial resonator 24.

[0007]

[Problems to be solved by the device]

 The conventional BEF and BPF described above include capacitors 21 to 23, coils L1 and L2, coupling terminals T1 to T3, coupling pins P1 and P3, a metal case in addition to the dielectric coaxial resonators R1 to R3 and 24 and the coupling substrate 20. It is composed of many parts such as 31 and has a complicated structure. For this reason, the number of assembling steps increases, manufacturing is difficult, and the cost is disadvantageous.

The present invention has been made in view of the above problems, and an object thereof is to provide a dielectric filter having a simple structure with a small number of parts.

[0009]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a plurality of dielectric coaxial resonators formed in an array, and the dielectric coaxial resonators are arranged to face each other so as to cascade-connect the dielectric coaxial resonators. A dielectric filter comprising a coupled substrate, wherein the dielectric coaxial resonator has a first electrode formed at a position where a central conductor is formed on an open end surface, and the coupled substrate is a surface facing the open end surface. A second electrode is formed at a position facing the first electrode, and the dielectric coaxial resonator and the coupling substrate are coupled by the capacitance formed between the first electrode and the second electrode. It is the one.

[0010]

[Action]

 According to the present invention, the dielectric filter is constructed by attaching a coupling substrate to the open end face of the dielectric coaxial resonator. The coupling substrate is attached with the surface on which the second electrode is formed facing the open end surface of the dielectric resonator. At this time, the second electrode formed on the coupling substrate is arranged with a predetermined gap from the first electrode formed at the position where the center conductor is formed on the open end face of the dielectric coaxial resonator. Each dielectric coaxial resonator is coupled to the coupling circuit of the coupling substrate by the capacitance formed between the first electrode and the second electrode, and the filter circuit is completed.

[0011]

【Example】

 FIG. 1 is a perspective view showing a structure of an embodiment of a dielectric filter according to the present invention.

The dielectric filter shown in the same figure is a three-stage BEF having the circuit configuration shown in FIG. The BEF 1 shown in the figure is composed of a dielectric coaxial resonator 2 and a coupling substrate 7. In the dielectric coaxial resonator 2, a dielectric 3 made of rectangular parallelepiped ceramics or the like in which three holes 4 are formed in parallel from one end face 31 to the other end face 32 is made of silver, copper, or the like. It is covered with a conductive member 6 (dotted portion), and is formed by integrally molding the three dielectric coaxial resonators θ1 to θ3 shown in FIG. A concave portion 5 having a diameter larger than that of the hole 4 is formed at the position where the hole 4 is formed on the one end face 31, and the dielectric member 3 except the peripheral portion of the bottom portion 51 of the concave portion 5 has the conductive member 6 formed therein. Is covered with.

The conductive member 6 covering the outer peripheral surface of the dielectric 3 forms an outer conductor, and the conductive member 6 covering the inner peripheral surface of the hole 4 forms a center conductor. Termination short-circuited quarter-wave dielectric coaxial resonators θ 1 to θ 3 are constituted by terminating by the conductive member 6 on the end face 32. The dielectric coaxial resonators θ1 to θ3 are coupled to each other by a magnetic field component formed in the dielectric 3. The electrodes D1 'to D3' formed on the bottom of the recess 5 are coupled to the conductive member 6 covering the inner surface of the recess 5 as shown in FIG. It forms C6.

FIG. 2 is a view showing the structure of the combined substrate 7. The coupling substrate 7 is made of a dielectric material such as ceramics and has a rectangular shape having substantially the same size as the one end surface 31 of the dielectric coaxial resonator 2. On the surface 71 of the substrate, three circular electrodes D1 to D3 are formed at predetermined positions facing the concave portion 5 when mounted on the dielectric coaxial resonator 2, and these electrodes D1 to D3 are formed. Pattern coils PL1 and PL2 are formed between D1 and D3. The pattern coils PL1 and PL2 correspond to the coils L1 and L2 of FIG. 4, respectively.

Further, lead wires 8 and 8 ′ that extend toward the short sides 72 and 72 ′ of the combined substrate 7 are formed on the electrodes D 1 and D 3 at both ends, respectively. These lead wires 8 and 8'further wrap around the side surface of the substrate and are formed on the rear surface 73 of the substrate for a predetermined length. The lead wires 8 and 8'may be extended from the long side of the combined substrate 7 to the substrate back surface 73 to form input / output terminals.

A convex portion 9 is formed around the substrate surface 71, and when the coupling substrate 7 is attached to the dielectric coaxial resonator 2, the electrodes (coupling circuit) formed on the substrate surface 71 are dielectric coaxial. It does not come into contact with the conductive member 6 covering the one end surface 31 of the resonator 2.

The coupling substrate 7 is attached to the one end surface 31 of the dielectric coaxial resonator 2 by bonding or the like so that the substrate surface 71 is on the dielectric coaxial resonator 2 side. An electrode for connection may be formed on the convex portion 9 of the coupling substrate 7, and the electrode and the conductive member 6 of the dielectric coaxial resonator 2 may be connected by soldering or the like to be attached.

When the coupled substrate 7 is attached to the dielectric coaxial resonator 2, the electrodes D1 to D3 formed on the substrate surface 71 are formed on the bottom of the recess 5 of the dielectric coaxial resonator 2 as shown in FIG. The electrodes C1 to C3 shown in FIG. 4 are formed so as to face the electrodes D1 'to D3', and the BEF1 is completed.

The capacitance values of the capacitors C1 to C3 can be set to desired values by adjusting the size or shape of the electrodes D1 'to D3' on the bottom of the recess 5. Further, as shown in FIG. 5, the height of the portion of the combined substrate 7 where the electrodes D1 to D3 are formed is increased, and the distance between the electrodes D1 'to D3' is adjusted to adjust each of the capacitors C1 to C3. The capacity value may be adjusted.

In the above embodiment, the projection 9 is provided around the surface 71 of the coupling substrate 7 so that the electrodes formed on the coupling substrate 7 serve as the conductive member 6 on the mounting surface (end face 31) of the dielectric coaxial resonator 2. As shown in FIG. 6, although the protrusions 9 of the coupling substrate 7 are removed, the electrode escape portion 15 is provided on the one end face 31 of the dielectric coaxial resonator 2 as shown in FIG. The formed electrode may not come into contact with the conductive member 6 on the mounting surface (end surface 31) of the dielectric coaxial resonator 2. In this embodiment, there is an advantage that the shape of the combined substrate 7 is simple.

Further, in the above embodiment, the coils L1 and L2 are composed of the pattern coils PL1 and PL2 formed on the coupling substrate 7, but as shown in FIG. 7, instead of the pattern coils PL1 and PL2, winding coils are used. You may make it connect ML1 and ML2. Further, when the winding coils ML1 and ML2 are connected between the electrodes D1 'and D2' and between the electrodes D2'D3 'of the combined substrate 7 in which the convex portions 9 are not formed, respectively, as shown in FIG. It is preferable to form a recess 5 ′ including three holes 4 in one end face 31 of the body coaxial resonator 2 so as to accommodate the winding coils ML 1 and ML 2.

Although the above embodiment is for the BEF, the BPF can also be configured with the same structure.

FIG. 9 is a perspective view of the essential parts showing the structure of an embodiment of the BPF using the dielectric coaxial resonator according to the present invention.

The BPF 10 shown in the figure is a three-stage dielectric filter having the circuit configuration shown in FIG. The dielectric coaxial resonator 11 is the same as the dielectric coaxial resonator 2 of the BEF 1 shown in FIG. It has a structure in which holes 13 and 13 'are formed. The inner peripheral surfaces of the holes 13 and 13 'are not covered with the conductive member 6. Since the dielectric coaxial resonator 11 does not include the conductive member 6 that covers the inner surface of the recess 5, capacitances corresponding to the capacitors C4 to C6 in FIG. 4 are not formed.

As shown in FIG. 10, the combined substrate 12 is obtained by removing the electrode D2 and the pattern coils PL1 and PL2 from the combined substrate 7 shown in FIG. In addition, in FIG. 9, the convex portion 9 is provided on the coupling substrate 7, but in the case of this BPF 10, the one end face 31 of the dielectric coaxial resonator 11 is not covered with the conductive member 6, so that the coupling substrate 7 is formed. The convex portion 9 may not be provided on 7.

When the coupled substrate 12 is attached to the dielectric coaxial resonator 11, the electrodes D1 and D3 formed on the surface 121 of the substrate are electrodes D1 ′ and D3 formed on the bottom of the recess 5 of the dielectric coaxial resonator 11. ′, And capacitors C1 ′ and C3 ′ shown in FIG. 10 are formed to complete the BPF 10.

Note that, when the coupling substrate 7 is attached to the dielectric coaxial resonator 2 by coating the side surface and the back surface of the substrate with the conductive member 6 as shown in FIG. 12, for example, the outer conductor of the dielectric coaxial resonator 2 is attached. You may make it connect with the electrically-conductive member 6 used as this. The combined substrate 12 can have the same configuration. By doing so, the shield of the coupling substrates 7 and 12 is improved, and the stability of the filter characteristics is improved.

In the above embodiment, the case where the dielectric coaxial resonators 2 and 11 in which the three dielectric coaxial resonators θ1 to θ3 are integrally formed is used is explained. However, a single dielectric coaxial resonator is used. It is also possible to construct the dielectric filter with the same structure by attaching the coupling substrates 7 and 12 to the ones in which θ1 to θ3 are aligned.

Although the three-stage BPF and BEF have been described, the present invention can also be applied to other multi-stage dielectric filters. It can also be applied to a dielectric filter such as an antenna duplexer, which is a combination of the BPF and BEF.

[0030]

[Effect of the device]

 As described above, according to the present invention, the first electrode is formed at the position where the central conductor is formed on the open end face of the dielectric coaxial resonator, while the position is formed so as to face the first electrode of the coupling substrate. A second electrode is formed on the surface of the dielectric coaxial resonator, and a coupling substrate is arranged facing the open end surface of the dielectric coaxial resonator, whereby a capacitance is formed between the first electrode and the second electrode. Since the dielectric coaxial resonator and the coupling substrate are combined to form a dielectric filter, the filter structure is simplified, the number of components is reduced, the number of assembly steps is simplified, and the cost is reduced. Contribute.

Further, in the case of the dielectric filters having the same number of stages, various filters can be configured by changing the coupling circuit of the coupling substrate, and the standardization of the product becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a structure of an embodiment of a BEF which is a dielectric filter according to the present invention.

FIG. 2 is a diagram showing a structure of a combined substrate of the BEF.

FIG. 3 is a vertical sectional view of the BEF.

FIG. 4 is a diagram showing a circuit configuration of the BEF.

FIG. 5 is a vertical sectional view showing the structure of the BEF in which the coupling between the coupling substrate and the dielectric coaxial resonator is increased.

FIG. 6 is a perspective view of an essential part showing another embodiment of the BEF.

FIG. 7 is a perspective view showing a structure in the case where a coil of the BEF circuit is formed of a winding coil on the coupling substrate side.

FIG. 8 is a perspective view of an essential part showing the structure of another embodiment in which the coil of the BEF circuit is formed of a winding coil on the coupling substrate side.

FIG. 9 is a perspective view of a main part showing a structure of an embodiment of a BPF which is a dielectric filter according to the present invention.

FIG. 10 is a perspective view showing a structure of a combined substrate of the BPF.

FIG. 11 is a diagram showing a circuit configuration of the BPF.

FIG. 12 is a view showing another embodiment of the combined substrate.

FIG. 13 is a main part perspective view showing an example of the structure of a BEF using a conventional dielectric coaxial resonator.

FIG. 14 is a perspective view of an essential part showing an example of the structure of a BPF using a conventional dielectric coaxial resonator.

[Explanation of symbols]

 1 BEF (Dielectric Filter) 2,11, θ1 to θ3 Dielectric Coaxial Resonator 3 Dielectric 4,13,13 'Hole 5,5' Recess 6 Conductive Member 7,12 Coupling Substrate 8,8 'Lead Wire 9 Convex Part 10 BPF (dielectric filter) 15 Electrode escape part 31,32 End face 71,121 Substrate front face 72 Substrate rear face C1 to C6, C1 'to C3' Capacitors L1, L2, ML1, ML2, PL1, PL2 Coils D1 to D3 D1 'to D3' electrodes

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Hisashi Mohri 2-26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Murata Manufacturing Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A dielectric comprising: a plurality of dielectric coaxial resonators formed in an array; and a coupling substrate arranged opposite to an open end face of the dielectric coaxial resonators so as to cascade-connect each dielectric coaxial resonator. A body filter, wherein the dielectric coaxial resonator has a first electrode formed at a position where a center conductor is formed on an open end face,
A second electrode is formed on a surface of the bonded substrate facing the open end surface at a position facing the first electrode, and the dielectric coaxial is formed by a capacitance formed between the first electrode and the second electrode. A dielectric filter characterized in that a resonator and the coupling substrate are coupled to each other.