Adjustable band-pass filter

Abstract

The invention provides an adjustable band-pass filter, which includes a filter main body located in an external magnetic field, wherein the filter main body comprises a resonant cavity, an upper substrate and a lower substrate arranged in the resonant cavity, a radio frequency input end arranged at one end of the resonant cavity and a radio frequency output end arranged at the other end of the resonant cavity, the upper substrate and the lower substrate are vertically opposite and arranged at an interval, the opposite surfaces are provided with microstrip lines, the radio frequency input end is connected with the microstrip line of the lower substrate, the radio frequency output end is connected with the microstrip line of the upper substrate, the upper substrate and the lower substrate are respectively provided with a YIG substrate, the YIG substrates are connected with the microstrip lines, each YIG substrate comprises a GGG substrate connected with the microstrip line and a YIG film arranged on the top surface of the GGG substrate, and a preset distance is formed between the surfaces of the YIG film of the upper YIG substrate and the lower YIG substrate. Through the structural design of the resonant cavity and the YIG substrate formed by the YIG film and the GGG substrate, the center frequency in a certain frequency band range is adjustable while the resonant cavity has the advantages of being simple in structure and easy to assemble.

Description

technical field [0001] The invention belongs to the technical field of radio frequency microwaves, and in particular relates to a band-pass filter with adjustable center frequency. Background technique [0002] Yttrium iron garnet (YIG) magnetically tuned filter, referred to as YTF, is a filter with tunable center frequency. In recent years, due to the demand for miniaturization in electronic countermeasures and test equipment, YIG magnetic modulation filters can be used as preselectors to replace the switching filter banks in receivers. By adjusting the size of the magnetic field and changing the center frequency of the filter, interference can be suppressed Signal, through the useful signal, so as to realize the small volume characteristics of the entire electronic system. In addition to the advantages of fast tuning within a wide frequency band of several octaves, the YIG magnetically tuned filter also has the advantages of high tuning linearity and high out-of-band reje...

AI Technical Summary

Problems solved by technology

However, in order to realize a filter with good performance, YIG balls need to go through a complicated polishing process to obtain small balls with precise dimensions, extremely low eccentricity and optical precision; at the same time, it is necessary to adjust the orientation of multiple YIG balls to achieve The easy axis is parallel to achieve synchronous tuning, which requires a complex tuning device to fine-tune the ball

Therefore, it is not easy to achieve mass production of products using YIG balls as harmonic oscillators

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