Wide stop-band coaxial single-cavity three-mode wideband filter using cross feeder

Abstract

The invention discloses a wide stop-band single-cavity three-mode wideband filter using a cross feeder. The filter comprises a cavity, a coaxial cavity solid inner conductor, a SMA radio frequency connection input port, a SMA radio frequency connection output port, an input end cross feeder main branch, an output end cross feeder main branch, an input end cross feeder external coupling branch, anoutput end cross feeder external coupling branch, an input end cross feeder internal coupling branch and an output end cross feeder internal coupling branch. The whole filter structure is a symmetricstructure about the symmetry plane A-A'. In the circuit structure with small size, the filter realizes wideband pass-band characteristics, wide stop-band range and high pass-band selectivity due to transmission zeros on both sides. Besides, the filter also has the characteristics of low dispersion and simple design and processing so as to meet the design requirements of small-scale wideband communication systems, and the filter can be applied to mobile communication, radar, satellite and other microwave electronic systems.

Description

technical field [0001] The invention relates to a cavity broadband filter, in particular to a wide-stop-band coaxial single-cavity triple-mode broadband filter using a cross-shaped feeder. Background technique [0002] In recent years, with the development of wireless communication technology, navigation technology and electronic countermeasures, the frequency bands occupied by the systems are getting closer and closer, and the communication devices are getting smaller and smaller. The design of the device puts forward higher and higher standards and requirements. Cavity filters have the characteristics of high power capacity, high quality factor, high stability, low loss, and good temperature characteristics, so they are often used in electronic equipment such as communication base stations, aviation, aerospace, radar, electronic countermeasures, and radio and television. . At the same time, since there is a certain inverse proportional relationship between the resonator ...

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Problems solved by technology

The advantage of this method is that the volume is relatively small, but the control is not as good as the first method

[0004] In the current research on cavity multimode broadband filters, there are two key issues that have not been resolved: 1. In all literatures on cavity multimode broadband filters, the FBW (relative bandwidth) of cavity three-mode broadband filters The maximum can only be 30%, and the market has a demand for wider bandwidth, such as making FBW greater than 40%, so how to break through the current upper limit of bandwidth is a key problem that needs to be solved urgently; 2. The parasitic mode of the cavity filter The harmonics of the filter seriously affect the stopband characteristics of the filter. How to suppress the harmonics or keep the harmonics away from the passband to achieve wide stopband characteristics is another key problem that needs to be solved urgently.

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