JPH03212003A - Waveguide type dielectric filter - Google Patents

Abstract

PURPOSE:To attain polarization with simple constitution by coupling part of a conductor film covering almost entire surface of a dielectric block with coupling conductors mutually, and isolating the coupled part from other film. CONSTITUTION:At least two coupling conductors 10 are provided, a part of them is provided in a dielectric block 1 and the other part reaches the surface of the dielectric block 1. Then a part 6 of the conductor film 2 covering almost all the surface of the dielectric block 1 is coupled with the coupling conductor 10 and the coupled part 6 is isolated from the other film. Thus, a polarized waveguide filter with simple constitution is realized without deteriorating the characteristic.

Description

[Detailed Description of the Invention] [Summary] Regarding a waveguide type dielectric filter, the purpose is to polarize it with a simple configuration, and it has a predetermined length in the axial direction and is perpendicular to the axial direction. A dielectric block having a rectangular cross section and having a plurality of through holes provided at predetermined intervals in the axial direction and in a direction perpendicular to the long side of the rectangle; A waveguide type dielectric filter comprising a conductive film covering the entire surface, comprising at least two coupling conductors, a part of which is installed inside the dielectric block, and a part of which reaches the surface of the dielectric block. However, the conductive film is formed such that a part of the conductor film connects the coupling conductors to each other, and the coupling part is isolated from other films.

[Industrial application field]

The present invention relates to a waveguide dielectric filter, and particularly to a polarized waveguide dielectric filter.

As a filter in the microwave band, it is necessary to miniaturize the device,
Although dielectric filters are widely used to improve performance, there is a demand for the development of dielectric filters that are smaller in size, have higher performance, and are easier to manufacture.

[Prior Art] A λ/4 resonant coaxial filter is generally used as a microwave band filter. FIG. 6 is a diagram showing an example of a five-stage λ/4 resonant coaxial filter.

Conductive metallization 2 is applied to five surfaces of the rectangular parallelepiped dielectric block 1 except for the top surface by baking etc., and the dielectric block 1 is
are provided with coupling holes 4, .about.44, and resonant conductors 3, .about.35, which are holes whose inner surfaces are conductor metallized.

In this type of filter, five resonant conductors 3, ~3
5, the resonant wavelength is set to λ due to the resonance of the TEM mode.
, a five-stage coaxial bandpass filter is formed.

It is generally said that the mutual coupling of each stage is due to magnetic field coupling, and the size of the coupling holes 41 to 4. It is adjusted by the size of The microwave is supplied from a terminal that is capacitively coupled to the resonant conductor 31 at the farthest end, and taken out from a terminal that is capacitively coupled to the resonant conductor 35 at the other end, which will be illustrated later.

Further, Japanese Patent Application Laid-Open No. 63-220603 describes a waveguide type dielectric filter which has a higher Q value than this coaxial type filter and is easier to manufacture because of its simpler structure.

FIG. 7 shows an example of a five-stage filter.

A rectangular parallelepiped dielectric block l is provided with conductive metallization 2 over almost its entire surface.

Pairs of through holes are provided at equal intervals in the axial direction, and conductor metallization is also applied to the inner surface of the through holes to form four pairs of coupling holes 8. The dielectric 1 is exposed in a concave shape at both end faces in the axial direction, and a microwave input end and an output end are formed, respectively.

Each of the five regions separated by the four pairs of coupling holes 8 is T.
An E+o+ mode resonance circuit is formed, and the strength of mutual coupling is adjusted by the size of the coupling hole 8.

By the way, in the above-mentioned dielectric filter, a polar circuit is added to form a pole in the frequency characteristic curve in order to attenuate a specific frequency in order to remove leakage of the local oscillation frequency, for example. .

An example of polarization in the coaxial filter shown in FIG. 6 is shown in FIG. (a) is a perspective view, and (b) is a sectional view. In the following drawings, the hatched portion in the cross-sectional view represents a surface on which conductive metallization is applied.

Capacitive coupling terminals 7 □ and 7° are inserted into the internal cavities of the resonant conductors 3 □ and 34 in order to capacitively couple them, respectively, and the two are coupled by a conductive pattern 6 formed on the dielectric substrate 5. .

With such a configuration, a resonant circuit centered around the resonant conductor 3□, that is, from the second stage resonator, to the resonant conductor 3.
In the resonant circuit centered on , that is, the path leading to the fourth resonator, a shunt is formed by the conductive pattern 6 in addition to a path by magnetic field coupling via the third resonator. By adjusting the phase change and amplitude change applied in this shunt, the phase difference for the specific frequency to be removed at the combining point of both can be made 180 degrees, and the amplitude can be made the same. Electromagnetic waves are attenuated and removed.

FIG. 8(a) shows an example of a conductive pattern in which a conductive pattern 6 is used for direct connection, but as will be described in detail later, various types of conductive patterns 6 can be used. Incidentally, the capacitive coupling terminals 7° and 75 are for inputting and outputting electromagnetic waves, respectively.

[Problem to be solved by the invention]

The waveguide type filter shown in FIG. 7 can also be constructed in the same manner as the coaxial type filter.

However, in this case, the number of parts increases, the size and shape become large and complicated, and the simplicity of the structure, which is one of the advantages of the waveguide type filter, is lost.

Therefore, an object of the present invention is to provide a polarized waveguide dielectric filter having a simple structure.

[Means to solve the problem]

The polarized waveguide dielectric filter according to the present invention has a predetermined length in the axial direction, has a rectangular cross section perpendicular to the axial direction, and has a cross section perpendicular to the axial direction and the long side of the rectangle. A waveguide dielectric filter comprising a dielectric block having a plurality of through holes provided at predetermined intervals in the axial direction, and a conductive coating covering almost the entire surface of the dielectric block. comprises at least two coupling conductors, a part of which is disposed within the dielectric block and a part of which reaches the surface of the dielectric block, the conductor coating having a part of which connects the coupling conductors to each other. It is characterized in that it is formed so that it is bonded and the bonded portion is isolated from other coatings.

[For production]

Since the bonding portion that interconnects the bonding conductors can be formed by removing a portion of the conductor coating,
Polarization does not increase the size and shape, and the structure remains simple.

Furthermore, as will be explained in detail later, it is known that there is little flow of high-frequency current in the axial center of the conductive film, including the long sides of the rectangular cross section, and this is why a pattern for coupling is formed in this region. If formed, there is almost no deterioration in characteristics.

Absolute Excuse] FIG. 1 is a diagram showing a first embodiment of a waveguide type dielectric filter according to the present invention. (a) is its perspective view (
b) is a sectional view. Components that are the same as those in FIG. 7 are given the same reference numerals and their explanations will be omitted.

Reference numeral 10 denotes a coupling electrode formed by applying conductive metallization to the entire inner surface of two coupling holes provided in the dielectric block 1. These are provided at the center of the second and fourth stage resonators, respectively, of the five stages of resonators separated by four pairs of coupling holes 8. In FIG. 1(b), although the coupling hole 8 is not on the cut plane, it is depicted as being on the cut plane for the sake of explanation. 6 is coupling electrode 1
This is a conductor pattern that connects 0 to each other, and is formed in a form isolated from other coatings by conductor printing, dipping, etching, etc.

FIG. 2 is a diagram showing a second embodiment of the waveguide type dielectric filter according to the present invention, and is shown only in a sectional view.

Unlike the example shown in FIG. 1, a metal terminal 11 is buried in the coupling hole instead of the coupling electrode 10, and one end of the metal terminal 11 is connected to the conductive turn 6.
connected to.

In either case, the conductor pattern 6 is formed in the axial direction of the waveguide at the center of the side surface including the long sides of the rectangular cross section of the waveguide. It is known that high-frequency current flows as shown in FIG. 3, and the current distribution in this region is sparse, so removing the conductor metallization in this region will hardly cause any deterioration in characteristics.

In the waveguide dielectric filter shown in FIG. 7, a coupling hole 8 may be provided in the center in some cases. In that case, the conductive pattern 6 may be formed to bypass it as shown in FIG.

In the explanation so far, the shape of the conductive pattern 6 has been shown as if it were a continuous linear pattern.
In practice, as shown in FIG. 5, various patterns are appropriately selected in order to obtain desired characteristics.

〔Effect of the invention〕

As described above, the present invention provides a polarized waveguide filter with a simple configuration without deteriorating the characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the invention, FIG. 2 is a diagram showing a second embodiment of the invention, and FIG. 3 is a diagram showing the state of high-frequency current in a waveguide filter. Fig. 4 is a diagram showing other examples of conductive patterns, Fig. 5 is a diagram showing various conductive patterns, Fig. 6 is a diagram showing an example of a coaxial type filter, and Fig. 7 is an example of a waveguide type filter. FIG. 8 is a diagram showing an example of a polarized configuration of a coaxial filter. In the figure, (1)...Dielectric block, 2...Conductor metallization, 3,~35...Resonant conductor, 41~4. ... Coupling hole, 5... Dielectric substrate, 6... Conductor pattern, 71-7. ... Capacitive coupling terminal, 8... Coupling hole, 9... Dielectric exposed part, I
O...Coupling electrode, 11...Metal terminal, 12
...High frequency current. (b+) Figure 3 represents the state of high-frequency current Figure 3 Figure e:::=:■ (A) Open door (B) @m20 (C) Represents various conductive buttons 6 Figure 6 (b) An example of a coaxial dielectric filter Figure 8 (Example of polarization of a coaxial filter)

Claims (1)

[Claims] 1. having a predetermined length in the axial direction, a cross section perpendicular to the axial direction is rectangular, and provided at predetermined intervals in the axial direction and in a direction perpendicular to the long side of the rectangle. A waveguide type dielectric filter comprising a dielectric block (1) having a plurality of through holes and a conductive coating (2) covering almost the entire surface of the dielectric block, wherein a part of the dielectric block (1), with at least two coupling conductors (10, 11) disposed within the dielectric block, a portion of which reaches the surface of the dielectric block; Coupled conductor (
10, 11) are bonded to each other, and the bonded portion (6) is formed so as to be isolated from other coatings.