JPS6338881B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter device such as a filter or a duplexer using a coaxial resonator having a dielectric between inner and outer conductors.

When constructing a filter device, such as a duplexer, using a coaxial resonator having a dielectric material between the inner and outer conductors (hereinafter simply referred to as a dielectric coaxial resonator), two main structures can be considered.

One is the structure shown schematically in FIG. 1, as disclosed in Japanese Patent Application Laid-Open No. 56-57302. The other type is disclosed in Japanese Patent Application Laid-Open No. 56-57304, and has a structure as schematically shown in FIG. 2. In the one shown in Fig. 1, the inner conductors of dielectric coaxial resonators 2 are connected so as to hang from the signal propagation path 1, and a coupling capacitor C is connected between the inner conductors of adjacent dielectric coaxial resonators 2. Therefore, it is necessary to provide a cut-off space 3 on the open end side of each dielectric coaxial resonator 2. Here, the cut-off space is defined in size and shape so that adjacent dielectric coaxial resonators 2 are not coupled by electromagnetic waves, and therefore adjacent dielectric coaxial resonators 2 are coupled by a coupling capacitor C. Ru. However, sometimes unnecessary coupling may occur due to leakage signal components propagating along the inner surface of the case forming the cutoff space. Additionally, each dielectric coaxial resonator always requires one cutoff space, which hinders miniaturization. In the case shown in Fig. 2, the signal propagation path 1 and the dielectric coaxial resonator 2 are arranged so that their axial directions coincide, and the open ends of the 1/4 wavelength dielectric coaxial resonator 2 are coupled by a capacitor C. However, the shorted ends are magnetically coupled. Even in this structure, a cutoff space 3 is required on the open end side of the dielectric coaxial resonator 2, as in the example shown in FIG. Since the space 3 can be shared, the case can be made smaller accordingly. Also, unnecessary connections are less likely to occur. However, when configuring a filter, it is necessary to partially adopt an inductive (magnetic) coupling structure, which is structurally more complicated than capacitor coupling, and if the filter is assembled using capacitor coupling, some half-wavelength dielectric coaxial resonators may be used. must be used, which has the disadvantage of going against miniaturization.

Therefore, an object of the present invention is to provide a compact filter device that requires less cut-off space inside the case than the conventional filter device, has no unnecessary coupling, and can entirely adopt a capacitor coupling structure.

That is, the gist of the present invention is to provide a filter device using at least three or more dielectric coaxial resonators having a dielectric material between inner and outer conductors, in which first and second dielectric coaxial resonators are disposed on both sides of a signal propagation path. By distributing the resonators and arranging them so that their open ends face each other, the first and second dielectric coaxial resonators facing each other across the signal propagation path share one cut-off space, and the first , the second dielectric coaxial resonators are coupled by a capacitor, and the first,
This filter device is characterized in that one of the second dielectric resonators and a third dielectric coaxial resonator are coupled through a capacitor.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 3 illustrates the basic idea of this invention. In this way, the first and second dielectric coaxial resonators 2 that utilize coaxial TEM mode resonance are distributed on both sides of the signal propagation path 1 and arranged so that their open ends face each other. The second dielectric coaxial resonators 2, 2 share one cut-off space 3, and the stages are coupled by a capacitor that is more advantageous than dielectric coupling, and either the first or second dielectric coaxial resonator and a third dielectric coaxial resonator (the first,
This refers to dielectric resonators 2 arranged side by side with second dielectric resonators 2, 2. ) is combined with a capacitor, resulting in an extremely rational arrangement.
A filter that is small, has no unnecessary coupling, and has a simple structure suitable for mass production can be obtained. The dielectric coaxial resonator 2 itself is well known, but to be sure, it will be explained with reference to FIG. 4.The 1/4 wavelength dielectric coaxial resonator 2
The inner conductor 22 and the outer conductor 23 are formed by baking silver paste on the inner wall surface and outer circumferential surface of a cylindrical (cylindrical, rectangular cylinder, etc.) body 21 made of titanium oxide based ceramic dielectric, etc., or by electroless copper plating. At the same time, an inner conductor 22 and an outer conductor 2 are formed on the entire bottom surface in the figure.
An open end (top surface in the figure) is formed in the center hole to connect the inner conductor 22 and the outside.
A metal rod-shaped terminal 26 having a stopper collar 25 is inserted therein, and at this time, the terminal 26 and the inner conductor 22 are bonded together using a conductive adhesive. Note that the terminal 26 can have various other structures, but one example is shown in FIGS. 11 to 1.
As shown in FIG. 3, the terminal 90 includes a disc-shaped portion 91
, a plurality of tongue-shaped contact parts 92 extending radially from the periphery of the disc-shaped part 91 , a tongue-shaped connecting part 93 cut into a part of the disc-shaped part 91 toward the center, and a disc-shaped part 91 . A metal piece integrally formed with a stopper 94 extending radially from the periphery of the portion 91 to the necessary minimum length is attached to the contact portion 91.
2 is bent at about 90 degrees with respect to the disk-shaped portion 91 and the entire body is bent into a “he” shape to give it springiness, and the connection portion 93 is bent at an angle of about 90 degrees with respect to the disk-shaped portion 91.
Fold it in the opposite direction to 2. (See FIGS. 12 and 13) When the contact portion 92 is inserted into the center hole of the dielectric coaxial resonator 2, the contact portion 92 is pressed against the inner conductor 22. A connection with the outside, such as a capacitor electrode, for example, is soldered to the connection portion 93.
The shape of the contact portion 92, the connection portion 93, and the stopper 94,
The number is arbitrary.

FIG. 5 and subsequent figures show embodiments in which the present invention is applied to a duplexer.

5 and 6 show the arrangement inside the case 4 of the first embodiment. In FIG. 5, the right half shows six dielectric coaxial resonators used in the first filter section. 2 is the part assembled with the configuration shown in FIG. The left half is a part in which six dielectric coaxial resonators 2 used for the second filter part are assembled in a configuration as shown in FIG. The second filter section is connected to the first filter section by a coaxial cable or stripline 6. In the figure, 7 is a common input/output connector for the first and second filter parts, 8 is a dedicated input/output connector for the first filter part, and 9 is a dedicated input/output connector for the second filter part. The coupling capacitors used in the first and second filter sections may be ordinary capacitors that are individual components, but a more preferable example is a composite capacitor component 3 as shown in FIGS. 7 and 8.
It is conceivable to use 0.40. The composite capacitor component 30 has capacitor electrodes 32, 3 on one surface of a plate-like dielectric plate 31 made of a ceramic dielectric or the like.
3, 34, 35, 36, 37, 38, 39, and if used for the first filter part, the connector 7 or the center conductor of the stripline 6 would be connected to the electrode 32, and the electrode The terminal 26 of the first stage dielectric coaxial resonator 2 is connected to the terminal 33 at the upper end in the figure, and the terminal 26 of the second stage dielectric coaxial resonator 2 is connected to the electrode 34 at the lower end in the figure. The terminal 26 of the body coaxial resonator 2 is connected to the terminal 26 of the third stage dielectric coaxial resonator 2 at the upper end in the figure, and the terminal 26 of the third stage dielectric coaxial resonator 2 is connected to the electrode 35 at the upper end in the figure. The terminal 26 of the fourth stage dielectric coaxial resonator 2 is connected at the lower end, and the terminal 26 of the fifth stage dielectric coaxial resonator 2 is connected at the upper end in the figure. The terminal 26 is connected to the electrode 38, and the dielectric coaxial resonator 2 of the sixth stage is connected to the electrode 38 at the lower end in the figure.
The terminal 26 is connected to the electrode 39, and the connector 8 is connected to the electrode 39. Composite capacitor parts 30
is used for the second filter part, electrode 3
2 is connected to the center conductor of the stripline 6, and the electrode 39 is connected to the connector 9. The rest is the same as above. Composite capacitor parts 40
The capacitor electrode shape is composite capacitor part 3
In an example different from 0, the electrode 42 is the electrode 32,
Electrode 43 to electrode 33, electrode 44 to electrode 34,
The electrode 45 is connected to the electrode 35, the electrode 46 is connected to the electrode 36,
The electrode 47 is connected to the electrode 37, the electrode 48 is connected to the electrode 38,
Electrode 49 has a similar effect to electrode 39. In this way, the capacitor electrode can have any shape and is arbitrarily determined so as to obtain the required capacitance.

9 and 10 show the arrangement inside the case 50 of the second embodiment, and in FIG. 9, the same parts as those of the first embodiment are given the same numbers and explained. omitted. The difference from the first embodiment is that the connector 7 is arranged on one center line of the case 50, and the connectors 8 and 9 are arranged on the other center line. There is no difference in the area where you are.

Other possible structures as embodiments of the present invention include:
Although it has a structure in which the first and second filter parts are stacked, looking at each filter part, there is no difference in the part implementing the present invention.

As is clear from the above embodiments, the present invention provides a filter device using at least three or more dielectric coaxial resonators having a dielectric material between the inner and outer conductors. By distributing to the second dielectric coaxial resonator and arranging the open ends thereof to face each other, the first and second dielectric coaxial resonators facing each other across the signal propagation path form one cut-off space. First, let's share
A filter device in which second dielectric coaxial resonators are coupled together by a capacitor, and either one of the first or second dielectric resonators and a third dielectric coaxial resonator are coupled by a capacitor. As a result, only the minimum required cut-off space is required, making it possible to achieve a smaller size. Also, unnecessary coupling is less likely to occur, and the above-mentioned effects are obtained with a simple coupling structure of capacitor coupling, which is extremely complete compared to conventional examples. A filter device with high efficiency can be obtained.

[Brief explanation of the drawing]

1 and 2 are schematic explanatory diagrams of a conventional example, FIG. 3 is a schematic explanatory diagram of the present invention, FIG. 4 is a sectional view of a dielectric coaxial resonator, and FIG. 5 is a schematic diagram of an embodiment of the present invention. Internal layout diagram, Figure 6 is also an internal layout diagram seen from the side, Figure 7 is a plan view of the composite capacitor parts, Figure 8
The figure is a plan view of another composite capacitor component, FIG. 9 is an internal layout diagram of another embodiment of the invention, and FIG. 10 is an internal layout diagram similarly seen from the side.
FIG. 11 is a developed view of the terminal, FIG. 12 is a plan view, and FIG. 13 is a side view. 1 is a signal propagation path, 2 is a dielectric coaxial resonator, 3 is a cut-off space, C is a capacitor, and 90 is a terminal.

Claims (1)

[Claims] 1. In a filter device using at least three or more dielectric coaxial resonators having a dielectric between inner and outer conductors, first and second dielectric coaxial resonators are disposed on both sides of a signal propagation path. By distributing the resonators and arranging them so that their open ends face each other, the first and second dielectric coaxial resonators facing each other across the signal propagation path can share one cutoff space, and 1. The second dielectric coaxial resonators are coupled to each other by a capacitor, and further, either one of the first or second dielectric resonators and a third dielectric resonator are coupled to each other by a capacitor. Characteristic filter device.