Dielectric filter

Abstract

A dielectric filter provided by the invention comprises a cuboid ceramic dielectric block, a resonance hole formed in the dielectric block, a conductive layer covering the surface of the dielectric block and a shielding shell formed by vertically bending a metal plate twice, the shielding shell comprises a first vertical plate, a horizontal plate and a second vertical plate which are connected in sequence, the first vertical plate is connected to the rear surface of the dielectric block in a welded mode, the horizontal plate is located above the dielectric block and is parallel to the upper surface of the dielectric block, and the lower end of the second vertical plate is connected to the upper surface of the dielectric block in a welded mode. A stress release groove is formed in the shielding shell, the stress release groove extends upwards from the lower end surface of the second vertical plate, and the stress release groove penetrates through the right-angle connection part of the second vertical plate and the horizontal plate and extends to the horizontal plate, so that the stress release groove penetrates through the second vertical plate and the horizontal plate, the stress between the shielding shell and the dielectric block during thermal expansion and cold contraction can be eliminated, the damage of the conductive layer and the dielectric block is avoided, the performance of part of finished products can be finely adjusted, the operation is convenient, and time and labor are saved.

Description

technical field [0001] The present application relates to the technical field of communications, and in particular to a dielectric filter. Background technique [0002] Dielectric filter (English Dielectric filter) is designed and manufactured by using the characteristics of low loss, high dielectric constant, frequency temperature coefficient and thermal expansion coefficient of dielectric ceramic materials, and can withstand high power. Ladder lines connected in series or parallel. [0003] Most of the existing dielectric filters include a ceramic dielectric block, a resonant hole opened on the dielectric block, a conductive layer covering the surface of the dielectric block and the inner wall surface of the resonant hole, and a metal shielding shell connected to the dielectric block. The shielding shell is usually used with the The conductive layer on the surface of the dielectric block is fixed by welding. In order to facilitate welding and positioning, shallow grooves ...

AI Technical Summary

Problems solved by technology

[0003] Most of the existing dielectric filters include a ceramic dielectric block, a resonant hole opened on the dielectric block, a conductive layer covering the surface of the dielectric block and the inner wall surface of the resonant hole, and a metal shielding shell connected to the dielectric block. The shielding shell is usually used with the The conductive layer on the surface of the dielectric block is fixed by welding. In order to facilitate welding and positioning, shallow grooves are also provided on the dielectric block to match the shielding shell. When performing temperature shock tests or temperature cycle tests on dielectric filters, due to There is a certain difference between the thermal expansion coefficient of the dielectric block and the thermal expansion coefficient of the shielding shell. When thermal expansion and cold contraction, the dimensional changes of the shielding shell and the dielectric block are not the same, and the dimensional change along the long side is the most obvious. It is easy to separate the conductive layer If it is torn from the dielectric block, or the dielectric block is cracked, even if no obvious damage occurs, stress will be formed at the connection between the shielding case and the dielectric block. After a long time, the stress will easily cause the shielding case, the dielectric block and the conductive layer The poor contact will affect the performance of the dielectric filter

[0004] During the process of forming and coating the conductive layer of the existing ceramic dielectric block, due to the existence of fine collapse deformation and the fine edge of the conductive layer, there are some cases where the performance of the finished product is outside the allowable range, but not much. Although the performance of some finished products can be adjusted by grinding the dielectric block and the conductive layer, it is necessary to precisely control the degree of grinding to avoid deformation and cracking of the dielectric block, which is inconvenient, time-consuming and laborious to operate.

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