A small coaxial cavity three-band filter

Abstract

The invention discloses a small coaxial cavity three-frequency filter. The small coaxial cavity three-frequency filter includes a first coaxial cavity, a second coaxial cavity, an input port, an output port, a coupling piece loaded by a first Chinese character Wang-shaped three section, a coupling piece loaded by the second Chinese character Wang-shaped three section, a resonator loaded by a firstcoaxial three-piece slice, a resonator loaded by a second coaxial three-piece slice, and a coupling window, wherein the entire filter is a symmetrical structure about a center plane of the coupling window The small coaxial cavity three-frequency filter is advantaged in that not only the cavity three-frequency filter with the controllable frequency is achieved, but also miniaturization of the filter is achieved, high power capacity, large frequency ratio, wide stop band and simple design and processing are achieved, design requirements of small three-frequency communication systems can be met,and the three-frequency filter can be applied to microwave electronic systems such as mobile communication, radars and satellites.

Description

technical field [0001] The invention relates to a cavity filter, in particular to a small coaxial cavity three-frequency filter. It belongs to the field of microwave technology. Background technique [0002] With the rapid development of wireless communications, spectrum resources are becoming increasingly scarce. In order to reduce communication costs and improve spectrum utilization, tri-band filters, as a commonly used multi-band filter next to dual-band filters, have become a research hotspot because they are compatible with three different standards of key components in the front-end of tri-band communication systems. . Because of the advantages of low insertion loss, high Q value (quality factor), high power capacity and high stability, coaxial cavity tri-band filters have been widely used in highly selective narrowband communications, especially in coaxial cavity The main radio frequency filter is still one of the key equipment in mobile communication base stations...

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Problems solved by technology

like figure 1 As shown, the filter has good passband characteristics of three frequencies, but there are three problems: 1. The size is large, and there is too much redundant space in the entire cavity; 2. The frequency ratio of the passband is too small, of which 3 The center frequencies of the two passbands are 3.65GHz, 3.8GHz and 4GHz respectively; 3. The stopband characteristics are poor, the first harmonic appears at 4.5GHz, and the stopband is too narrow to affect practicality

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