Tunable filter and tunable duplexer

Abstract

The invention discloses a tunable filter, which comprises a cavity and a tuning mechanism. At least three waveguide resonant cavities are arranged in the cavity, direct coupling is realized between adjacent waveguide resonant cavities through a direct coupling window, cross coupling is realized between non-adjacent waveguide resonant cavities through a cross coupling structure, at least one slit is arranged on the cavity wall at the same side of each waveguide resonant cavity, and the electrical length of each slit is less than the half-wavelength of the highest working frequency of the tunable filter; the tuning mechanism comprises a group of dielectric sheets and a driving mechanism, wherein the dielectric sheets are in one-to-one correspondence with the slits, and all the dielectric sheets can be simultaneously inserted into the corresponding waveguide resonant cavities at the same depth without friction through the corresponding slits under the driving of the driving mechanism. Theinvention also discloses a tunable duplexer. The tunable filter and the tunable duplexer have good out-of-band rejection characteristic, and in the whole tuning range, the relative position of the transmission zero and the bandwidth of the pass band is basically kept unchanged, and the echo of the filter is kept at a better level.

Description

technical field [0001] The invention relates to a filter, in particular to an adjustable filter and an adjustable duplexer. Background technique [0002] Tunable filters are an important part of microwave reconstruction systems, and are widely used in frequency hopping radio stations, electronic countermeasures, multifunctional receivers, dynamic frequency allocation systems, and point-to-point communication systems. The use of adjustable filters can greatly reduce the material and maintenance costs of communication equipment manufacturers. Taking point-to-point communication as an example, an adjustable filter can replace dozens of conventional filters, so it can greatly reduce the number of types of ODU equipment. Greatly reduce production, storage, transportation and maintenance costs. Therefore, it is a hot research field in the microwave communication industry at present. Common tunable filters are mostly realized by means of radio frequency switches to control loadin...

AI Technical Summary

Problems solved by technology

Adding a resonant cavity means increasing the insertion loss of the filter, and the volume, weight and cost will all increase

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