RU130146U1 - CERAMIC MICROWAVE FILTER QUASI-PLANAR TYPE - Google Patents

Abstract

A quasiplanar ceramic microwave filter consisting of two monolithic ceramic blocks interconnected by faces with identical metallization in the form of an E-planar diaphragm, on the remaining faces of which a continuous metallization is applied, while on the end faces of the blocks, with the transition to the lower faces, the input and output communication elements.

Description

The utility model relates to microwave radio engineering and is intended for use in frequency selection devices of the centimeter and millimeter wavelength ranges.

In the indicated wavelength ranges, hollow-waveguide filters such as a chain of directly coupled resonators are used, in which transverse capacitive and inductive diaphragms, inductive rods, and capacitive pins act as shunt reactances (N. Semenov, “Technical Electrodynamics”) a also E-plane diaphragms (Sinyavsky GP, “Quasiplanar waveguide filters with improved characteristics”).

The use of planar technology elements in the manufacture of quasiplanar type filters ensures the manufacturability and low cost of these filters in serial production.

A design variant of a quasiplanar type filter is presented in US 2004/0017272 Al, Jan. 2004.2004.

The main disadvantages of filters of this type are their significant overall dimensions and weight, low temperature stability, the complexity of the layout of such filters on the circuit board with devices on microstrip and coplanar lines.

These disadvantages are largely eliminated in ceramic waveguide filters on thermostable ceramics with high dielectric constant. A known design of a ceramic waveguide filter, consisting of a metallized ceramic block in the form of a rectangular parallelepiped, in which a chain of cavity resonators is formed with direct coupling through flat transverse inductive diaphragms made in the form of metallized grooves on the side of the narrow walls of the ceramic block, with coupling elements in the form of capacitive platforms on the lower edge of the block (patent US 2009/0231064 A1, Sep. 17.2009) or in the form of short-circuited segments of the coplanar line on the lower edge of the block ( US patent 6,677,837 B2, Jan. 13.2004).

The main disadvantage of filters of this type is their low mechanical strength due to the large number of additional structural elements, such as grooves and holes.

Closest to the proposed technical solution are the design of waveguide ceramic filters (US patents No. 6,677,837, RU No. 2462799). Filters have high operational performance, however, in the first case, the presence of grooves of various depths or widths in the ceramic block makes it difficult to mass production, and also reduces the mechanical strength of the ceramic block, and in the second case, each filter type requires its own mold that implements the required size and location of holes.

The technical problem to which the utility model is directed is to increase the manufacturability of microwave filters, increase the mechanical strength, and also the ability to arrange such filters on a circuit board with devices on microstrip and coplanar lines.

To solve the technical problem, a ceramic quasiplanar microwave filter is proposed, consisting of two partially metallized blocks in the form of a rectangular parallelepiped made of high-quality thermally stable ceramics, interconnected by narrow faces with metallization in the form of an E-plane diaphragm, which forms chains of resonators in the connected filter blocks direct connection. At the end faces of the blocks, input and output communication elements are implemented.

The manufacturability of the design and the mechanical strength of the filter are ensured by the use of simple forms of ceramic blocks in the form of a parallelepiped without additional structural elements (grooves, holes), which makes it possible to group mechanically process and metallize the surfaces of ceramic blocks.

Figure 1-figure 3 presents the design of ceramic four-resonator microwave filters of quasi-planar type.

Figure 4 presents the amplitude-frequency characteristic of the filter.

Moreover, in figure 1-figure 3 and hereinafter:

Pos.1 - the first monolithic ceramic block;

pos.2 - the second monolithic ceramic block;

Pos. 3 - E-plane diaphragm;

pos.4 - input communication element;

pos.5 - output communication element;

LI is the width of the first monolithic ceramic block;

L2 is the width of the second monolithic ceramic block.

The filter shown in figure 1, consists of interconnected two monolithic ceramic blocks pos. 1 and pos. 2, on all faces of which, except for the adjoining faces, continuous metallization is applied. Ceramic blocks pos. 1 and pos. 2 are made in the form of rectangular parallelepipeds made of thermostable ceramic material, interconnected by faces with identical metallization in the form of an E-plane diaphragm pos. 3. The appearance of the metallization pattern is determined by the required filter parameters and may have a different configuration. The input pos. 4 and output pos. 5 communication elements are formed on the lower face of the ceramic block pos. 1 in the form of open segments of coplanar lines at the ends and short-circuited segments of coplanar lines at the end faces of the ceramic block. Block pos.2 has the same dimensions as block pos.1, except for size L2. By changing the size of L2, you can adjust the center frequency of the passband with a slight change in other filter parameters.

In the filter shown in figure 2, the input communication element pos.4 is formed in the above manner on the block pos.1, and the output communication element pos.5 on the block pos.2.

In the filter shown in Fig. 3, the input pos. 4 and output pos. 5 communication elements are formed on the lower faces of the ceramic blocks pos. 1 and pos. 2 in the form of open segments of coplanar lines and short-circuited segments of coplanar lines on the end faces of ceramic blocks pos. 1 and pos. 2.

It should be noted that, despite the fact that the utility model is illustrated by the image of filters having four resonators, the number of resonators may be different. The number of resonators is determined by the required filter characteristic and is limited by the permissible filter losses.

Figure 4 presents the amplitude-frequency characteristic of the filter of the centimeter frequency range, while the proposed design can be applied in the millimeter frequency range.

Ceramic microwave filter with E-plane diaphragms works as follows.

After the microwave signal arrives at the communication input element, item 4, energy is effectively input into the filter, which is a chain of resonators with direct coupling formed in a metallized ceramic block using the E-plane diaphragm item 3. The energy output is carried out by means of the output communication element pos.5. The type of filter characteristic is determined by the distribution of loaded Q-factors included in the chain of coupled resonators, which in turn is determined by the configuration of the E-plane diaphragm.

Claims (1)

A quasiplanar ceramic microwave filter consisting of two monolithic ceramic blocks interconnected by faces with identical metallization in the form of an E-planar diaphragm, on the remaining faces of which a continuous metallization is applied, while on the end faces of the blocks, with the transition to the lower faces, the input and output communication elements.

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