A multi-cavity coaxial electronically tuned filter

Abstract

The invention discloses a multi-cavity coaxial electric tuning filter, which includes a transmission mechanism, a filter and a linear motor controlled by a drive circuit. The linear motor includes a drive screw and a drive nut. One end of the drive screw is connected from the The inside of the linear motor protrudes, and the other end is fixed on the guide plate by a drive nut. The filter includes first to Nth resonant cavities with the same structure, N≥2. The box body of the first resonant cavity is provided with an inner conductor and a tuning rod, one end of the tuning rod is movably connected with the guide plate, and the other end extends into the inner conductor of the first resonant cavity, and the length of the tuning rod is adjustable. The inner conductor is provided with an elastic connection device, an O-ring and a sleeve that are nested and installed sequentially from the inside to the outside. Electric connection. The invention improves the stability of the filter, optimizes the stop band characteristics of the radio frequency filter, improves the stop band suppression degree of the cavity filter, and improves the anti-interference ability of the communication equipment.

Description

technical field [0001] The invention relates to an electric tuning filter, in particular to a multi-cavity coaxial electric tuning filter, which belongs to the technical field of microwave filters. Background technique [0002] In the prior art, the Chinese utility model patent with the patent number CN201220549062.4 discloses "a UHF band miniaturized electronically adjustable duplexer", and the Chinese utility model patent with the patent number CN201420768754.7 discloses "a wide-tuned synchronous Shaft ESC filter", the stepper motors used are reactive or hybrid stepper motors, and the motor and transmission mechanism are connected by gear transmission or coupling, which is not only difficult to process and assemble, but also relatively large in size. Transmission accuracy is also reduced due to gear clearance or coupling assembly accuracy. In the case of high operating frequency requirements, the frequency positioning accuracy cannot meet the requirements. [0003] In th...

AI Technical Summary

Problems solved by technology

In order to obtain the filtering performance of the multi-cavity band-pass filter, two four-cavity electronically tuned band-pass filters are usually cascaded, but this method of sacrificing volume for anti-interference ability has low superposition efficiency of stop band characteristics and large difference loss , under the requirements of miniaturized equipment, it can no longer meet the requirements

[0004] In addition, the transmission mechanism in the prior art uses a direct connection between the guide plate and the guide rod, and when the load is heavy, the guiding effect is not good

Especially in the case of simultaneous linkage of multiple resonant cavities, the overall assembly error of the transmission mechanism makes the transmission of the filter not smooth, and the load capacity requirements of the motor are increased.

The top of the original inner conductor of the coaxial cavity electric tuning filter is a comb-shaped shrapnel, the forming process of metal materials has a long production cycle and low yield

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