A Miniaturized Hexagonal Three-mode Filter Based on Central Branch Loading

Abstract

The invention relates to a small-scale hexagonal three-mode filter based on center branch knot loading. The filter comprises a resonance part, a dielectric substrate, a ground plate, a coupling line and a feeder line. On the basis that an annular hexagonal resonator is utilized as a basic filter structure, interdigital line variation is carried out on three nonadjacent edges of the hexagon, the working frequency of a degenerate fundamental mode is reduced, and a round paster branch knot is utilized for loading in the center of the resonator to introduce a new resonance mode, so that the filter is deeply miniaturized and the bandwidth is greatly extended. By means of the small-scale hexagonal three-mode filter, the bandwidth of a pass band can be increased effectively, parameters of the filter can be tuned under the situation that miniaturization and band spreading are achieved, the filtering requirements of needed frequency bands are met, it is unnecessary to redesign a new filter, the design time of the filter is shortened, and the filter has universality in actual engineering design.

Description

technical field [0001] The invention belongs to the technical field of filters, and relates to a miniaturized hexagonal three-mode filter based on central branch loading. Background technique [0002] With the leap-forward development of modern mobile and wireless communication systems, wireless communication systems have higher and higher requirements on circuit size and signal quality. As a key device for extracting and suppressing signals at the front end of the radio frequency, the filter's performance directly affects various indicators of the communication system, which puts forward very strict indicator requirements for the design of the filter. Considering both low-size and high-performance filter design is one of the efforts of microwave engineers in recent years, and has become a research hotspot and difficulty in microwave passive devices in recent years. In the actual design and production process of the filter, in addition to meeting the basic performance requi...

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Problems solved by technology

However, the degree of miniaturization achieved by the above methods is limited by the operating frequency of their respective fundamental modes, which limits the further reduction of the overall size of the filter.

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