Ku band ultra-narrow bandwidth microstrip bandpass filter

Abstract

The invention provides a Ku band ultra-narrow bandwidth microstrip bandpass filter, which comprises a microstrip substrate, wherein the reverse side of the microstrip substrate acts as a grounding metal plate, two sides of the microstrip substrate are provided with a first input / output port and a second input / output port respectively, the obverse side of the microstrip substrate is provided with a first uniform transmission line unit, a second uniform transmission line unit, a first coupling feeder, a second coupling feeder, a third coupling feeder, a fourth coupling feeder, a first open-circuit branch knot, a second open-circuit branch knot, a first folded L-shaped structure unit, a second folded L-shaped structure unit, a rectangular structure unit, a third open-circuit branch knot and a fourth open-circuit branch knot. The Ku band ultra-narrow bandwidth microstrip bandpass filter is good in selectivity, high in out-of-band rejection ratio, small in size, light in weight, planar and low in cost.

Description

technical field [0001] The invention belongs to the technical field of microwave transmission devices, in particular to a Ku-band ultra-narrow-band microstrip bandpass filter. Background technique [0002] With the development of microwave and millimeter wave communication, radar and other systems, microstrip circuits are widely used in modern communication systems due to their advantages of small size, light weight, wide frequency band, and easy matching with radio frequency circuits. The Ku-band ultra-narrow-band microstrip band-pass filter is a key electronic component in the way of receiving and transmitting in this band, and its performance often affects the performance indicators of the entire communication system. Therefore, the Ku-band ultra-narrowband filter with small size, light weight, planarization, good in-band selectivity, and high out-of-band rejection has strong theoretical significance and engineering application value. [0003] Existing literature reports...

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Problems solved by technology

[0004] Document 1 (Zhao, G.Q., Z.Zhang, X.Lv, and H.J.Sun, A Ku Band Waveguide Bandpass Filter With E-plane Metallic Diaphragm, Microwave and Millimeter Wave Technology (ICMMT), 2010:875-877) uses A Ku-band bandpass filter is designed in the form of a waveguide. Although the insertion loss is small and the structure is simple, the overall size is large, and the center frequency and bandwidth are not easy to adjust;

[0005] Document 2 (Guo, Z.Q., Q.Chen, and Y.Fan, A Compact Ku-Band Filter Based On Substrate Integrated Circular Cavity, Intelligent Signal Processing and Communication Systems (ISPACS), 2010: 1-3) uses integrated media A Ku-band bandpass filter is designed in the form of a waveguide. Although the volume is reduced, it increases the processing difficulty and production cost, and the selectivity of the passband is not ideal;

[0006] Document 3 (Jiang, S.L., J.M.Zhou, and J.Zhou., A LTCC-Based Ku-band3D Bandpass Filter Using Stepped-Impedance Hairpin Resonators, Microwave and Millimeter Wave Technology (ICMMT), 2012:1-4) uses A Ku-band bandpass filter is designed in the form of low-temperature co-fired ceramic technology. Although the volume is small and the performance is good, the structure is not easy to integrate in the microwave circuit module, and the out-of-band rejection is not high;

[0007] To sum up, Document 1 designs a Ku-band bandpass filter in the form of a waveguide. Although the insertion loss is small and the structure is simple, the overall size is large; in Document 2, a Ku-band bandpass filter is designed in the form of an integrated dielectric waveguide. Although the volume of the band-pass filter is reduced, it increases the processing difficulty and production cost; in Document 3, a Ku-band band-pass filter is designed by using low-temperature co-fired ceramic technology. Although the volume is small, the performance Very good, but this structure is not easy to integrate in the microwave circuit module; moreover, the band-pass filters of the Ku-band designed in Documents 1, 2 and 3 are all broadband Ku-band band-pass filters

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