Double-frequency band-pass filter

Abstract

The invention provides a double-frequency band-pass filter, which belongs to the design field of microwave and millimeter wave devices. The filter comprises a first metal patch, a second metal patch and a medium substrate, wherein the two metal patches are respectively wrapped on the upper surface and the lower surface of the medium substrate; the first metal patch consists of an input feeder line, an output feeder line and two three-mode stepped impedance resonators; the two resonators are respectively provided with three metallized through holes; and three metallized through holes corresponding to the first metal patch are arranged on the second metal patch. The double-frequency band-pass filter is designed by using two three-mode stepped impedance resonators which are loaded by stub lines; each resonator can generate and independently control a pass band; the bandwidths of the two pass bands are respectively 15.4 % and 10.2 %; four transmission zero points are generated, so that the band-pass filter has the characteristics of high frequency selection performance, independent pass band control, low cost, high performance, small size and adjustable pass band widths.

Description

technical field [0001] The invention relates to a high-selectivity dual-frequency microstrip bandpass filter, which belongs to the design field of microwave and millimeter wave devices. Background technique [0002] In recent years, with the rapid development of wireless communication systems, radio frequency devices with dual-frequency characteristics have broad application prospects. In a traditional dual-frequency communication system, each communication system has its own independent antenna, filter, LNA and other components, resulting in relatively large volume and loss of the entire system. If the above radio frequency components are all designed as dual-frequency systems, the volume of the entire dual-frequency communication system will be reduced by half, and the power consumption will be greatly reduced, which is convenient for system integration. As a key component of the RF front-end, the performance of the dual-band band-pass filter directly affects the performa...

AI Technical Summary

Problems solved by technology

The first is to cascade a band-pass filter and a band-stop filter, the problem is that the size is larger [2]

The second is to use stepped impedance resonators [3-5] , the two resonant frequencies of the resonator can be controlled by adjusting the impedance ratio and electrical length of the two parts, but the bandwidths of the two passbands are difficult to be independently adjustable, and the frequency selectivity of the filter is poor

In reference [8], a kind of broadband bandpass filter is designed by using the stepped impedance resonator loaded by the stub, which realizes the characteristics of dual passband and miniaturization, but the frequency selectivity still needs to be improved

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