JPS5829883B2 - filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter, and more particularly to a filter using, for example, a quarter wavelength coaxial TEM resonator.

Conventionally, filters used in the VHF band or UHF band include those using an LC resonator and those using a coaxial resonator.

However, the former did not have sufficient selection characteristics, and the latter had the disadvantage of having a narrow shape.

In recent years, in the field of communication equipment, there has been a desire to make systems smaller and lighter.While other components are being made smaller and lighter, filters are still being used despite their importance. However, because it was difficult to make the system smaller and lighter, it was delayed in making the system smaller and lighter.

Therefore, reducing the size and weight of filters has been a technical proposition for engineers in this field.

Therefore, the main object of the present invention is to provide a filter that can be made smaller.

To summarize, this invention arbitrarily stores a plurality of 1/4 wavelength coaxial TEM resonators in two or more parallel holes in a case made of a conductor, and connects each resonator with an inner conductor and an outer conductor. A dielectric resonator with a dielectric between the
This is a filter in which the voltage open ends of each resonator are coupled by capacitance, and the voltage short ends of each resonator are coupled by an inductive coupling window.

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

In terms of construction, the case 1 is a rectangular rectangular body made of a conductor such as duralumin, with holes 2, 3 and 4 cut out therein.

1a is an upper pig, and 1b is a lower pig.

Two quarter-wavelength coaxial TEM resonators 5, 5 are housed inside the holes 2, 3, and 4, respectively.

Each of the quarter-wavelength coaxial TEM resonators 5 has a dielectric material 8, such as a titanium oxide ceramic dielectric material, between an inner conductor 6 and an outer conductor 7, as shown in FIG. exists and consists of

That is, this 1/4 wavelength coaxial TEM resonator 5 has an inner conductor 6'' made by baking a material, for example, silver paste, which has excellent high frequency conductivity and good adhesion to the dielectric, on the inner wall and outer periphery of the dielectric 8. Let J=- and outer conductor 7.

Moreover, each resonator 5, 5 . The interior of the dielectric body 8 and therefore the inner conductor 6 is hollow, and therein is preferably a central rod 9, 9 made of a similar ceramic or the like for reinforcement.
．． ... is inserted.

An input coupling capacitor 10 is provided on the input side of the 1/4 wavelength coaxial TEM resonator 5 in the first stage, and an output coupling capacitor 11 is provided on the output side of the 1/4 wavelength coaxial TEM resonator 5 in the 6th stage. be combined.

These coupling capacitors 10 and 11 are formed by providing electrodes on both end faces of a cylindrical dielectric body, for example, one electrode is connected to the inner conductor 6 of the resonator 5, and the other electrode is connected to a conductive wire facing the input side. The button on the output side is connected to an input coaxial connector 13 via a conductor 12, and an output coaxial connector 15 via a conductor 14.

The 1/4 wavelength coaxial TEM resonator 5, 5. ... is 1
/4 wavelength resonator, the thick end becomes the short-circuit side and the other end becomes the open side.

This resonator 5,5. . . , their open sides are coupled by capacitance, and their short-circuit sides are inductively coupled by a coupling electrode 16.

That is, the second stage 1/4 wavelength coaxial TEM resonator 5 and the third stage 1/4 wavelength coaxial TEM resonator 5. The fourth stage 1/4 wavelength coaxial TEM resonator 5 and the fifth stage 1/4 wavelength coaxial TEM resonator 5 are coupled by capacitance, and the first stage 1/4 wavelength coaxial TEM resonance TEM resonator 5, second stage 1/4 wavelength coaxial TEM resonator 5, and third stage 1/4 wavelength interaxial TEM resonator 5
M resonator 5 and fourth stage 1/4 wavelength coaxial TEM resonator 5
, the fifth stage 1/4 wavelength coaxial TEM resonator 5 and the sixth stage 1/4 wavelength coaxial TEM resonator 5 are coupled by a coupling electrode 16.

More specifically, the inner conductor 6 of the second stage 1/4 wavelength coaxial TEM resonator 5 and the inner conductor 6 of the third stage 1/4 wavelength coaxial TEM resonator are connected to a coupling capacitor 17. They are connected by a conducting wire 18 and a coupling capacitor 19.

The conducting wire 18 is inserted into the hole 2 formed by hollowing out the space between the holes 2 and 3.
0 to coupling capacitor 17.19.

Similarly, the inner conductor 6 of the fourth stage 1/4 wavelength coaxial TEM resonator 5 and the inner conductor 6 of the 5th stage 1/4 wavelength coaxial TEM resonator 5 are connected to the coupling capacitor 21. They are connected by a conducting wire 22 and a coupling capacitor 23.

The conductor 22 is inserted into the hole 2 formed by hollowing out the space between the holes 3 and 4.
4 to the coupling capacitors 21 and 23.

Further, the electrode 16 may have a structure as shown in FIGS. 4a and 4b.

That is, such an electrode 16 has an inductive coupling window 25 and a central hole 26.

The inductive coupling window 25 can adjust the coupling state between the resonators depending on its size, and although the center rod 9 is inserted into the center hole 26, it is not necessary to insert it therein.

The coaxial TEM mode is a point-symmetric mode, and breaking the symmetry will lead to deterioration of spurious characteristics due to higher-order modes. It is hoped that this will be formed.

In an electrode such as that shown in FIG. 4a, inductive coupling windows 25a and 25b
.

25c is bored in the circumferential direction, and these three connecting windows 2
5a, 25b + 25c each have three axes of symmetry.

Further, the electrode shown in FIG. 4bK has six coupling windows 25a to 25f, and each of these coupling windows 25a and 25f has six symmetry axes.

Such an electrode 16 is formed, for example, by baking silver paste or by using a thin silver or platinum plate.

Also, an inductive coupling window 25.25a bored in this electrode 16
It goes without saying that various shapes and patterns of ~25f can be used other than those shown in FIG.

The outer conductor 7 of each resonator 5 is fixed to the inner wall of the casing 2, 3 or 4 with a conductive adhesive for its fixing and electrical connection.

Alternatively, this may be fixed using screws, but each resonator 5, 5. It is heavy for the vehicle to be stored closely against the inner wall of holes 2, 3, or 4.

The filter of the present invention is not limited to the above-mentioned embodiments, and various modifications are possible.

The number of holes is not limited to three.

Furthermore, the number of resonators housed in each company is not limited to two.

The fixing positions of the input coaxial connector and the output coaxial connector to the case are not limited to those shown in the figure.

First, holes are provided according to the required case external dimensions and the length:width:depth ratio of the external dimensions, and the number of resonators to be accommodated in each company is determined.

In the above-described embodiment, the open ends of the resonators 2 are coupled by a capacitor, but they may be coupled by a stray capacitance.

The dielectric material 8 of each resonator need not be a single piece, and a plurality of dielectric materials 8 may be used in combination due to manufacturing problems.

Further, in the embodiment shown in FIG. 1, when (inner diameter of the outer conductor of the resonator)/(outer diameter of the inner conductor of the resonator) is set to about 3.6, Q reaches its maximum value.

Furthermore, by appropriately selecting the temperature coefficient of the dielectric 8,
Since the influence of the coefficient of linear expansion of the metal conductors such as the inner conductor 6 and the outer conductor 7 is canceled out, the temperature characteristics are excellent.

As described above, according to the present invention, since the dielectric material is present between the inner conductor and the outer conductor of the coaxial TEM resonator, the shape becomes extremely small, and the entire system such as a communication device becomes small and lightweight.

Therefore, it will make a great contribution to the field.

In addition, a 1/4 wavelength coaxial TEM with such a dielectric material
The resonators are coupled by inductive coupling or capacitive coupling, two or more holes are provided in parallel in the case made of a conductor, and the resonators are arbitrarily distributed in layers in these holes, so that the mutual positional relationship and coupling of the resonators is difficult. Since there are no indeterminate factors such as condition, and no special skill is required, assembly or manufacturing is easy, and the characteristics of the designed button can be obtained with excellent reproducibility.

Note that a 1/2 wavelength coaxial TEM resonator may be used if necessary.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a case used in an embodiment of the invention, and FIG. 2 is a sectional view of an embodiment of the invention. FIG. 3 is a plan view of the same with the top lid removed. 4A and 4B are schematic plan views showing a specific example of the electrode 16. FIGS. 1 is a case, 2, 3 and 4 are holes, 5 is a 1/4 wavelength coaxial TEM resonator, 6 is an inner conductor, 7 is an outer conductor, 8 is a dielectric,
10 is an input coupling capacitor, 11 is an output coupling capacitor, 16 is a coupling electrode, 17 is a coupling capacitor, 19 is a coupling capacitor, 21 is a coupling capacitor, 23 is a coupling capacitor, 25 is an inductive coupling window, and 25a to 25f are coupling windows.

Claims (1)

[Claims] 1. Two or more holes are provided in parallel in a flock made of conductor,
A plurality of ]/4 wavelength coaxial TEs consisting of an inner conductor, an outer conductor, and a dielectric material existing between the inner conductor and the outer conductor.
M resonators are arbitrarily arranged in the hole, the open ends of each of the 1/4 wavelength coaxial TEM resonators are capacitively coupled, and the short-circuited ends of each of the 1/4 wavelength coaxial TEM resonators are inductively coupled. Combined filter.