Half-mode substrate integrated waveguide bandpass filter based on s-type complementary helix

Abstract

The invention discloses an S-type complementary spiral line-based half-mode substrate integrated waveguide bandpass filter, and mainly aims to solve the technical problems of poor selectivity, narrow bandwidth, high insertion loss and the like of a filter. A circuit structure is designed on each of the upper and lower surfaces of a microstrip dielectric substrate separately; the upper surface comprises two symmetrical microstrip feeder lines and a metal rectangular surface; four L-shaped groove lines in mutual symmetry are arranged in the metal rectangular surface; an a pair of longitiduinally-symmetrical S-type complementary spiral line structures are arranged in the positions, corresponding to the areas of the L-shaped groove lines, of the lower surface of the microstrip dielectric substrate, wherein the complementary spiral line structure units are in rotation symmetry in a transverse direction. According to the novel structured half-mode substrate integrated waveguide bandpass filter, the circuits are symmetrical up and down, the units are symmetrical left and right and up and down, and a coplanar waveguide transitional structure is adopted for feeding; simulation and experiments prove that the out-of-band frequency selectivity of the filter is improved, the bandwidth is relatively high, the insertion loss is low, and the filter can be applied to a wireless communication system with requirements of a small size and a light weight.

Description

technical field [0001] The invention belongs to the technical field of electronic devices, in particular to a half-mode substrate integrated waveguide bandpass filter, specifically a novel half-mode substrate integrated waveguide bandpass filter based on an S-type complementary helix structure, which can be used in wireless Communication system radio frequency front end. Background technique [0002] With the development and innovation of modern wireless communication systems, microwave and millimeter wave systems are developing rapidly towards miniaturization, high integration, and low cost. The waveguide structure with low loss, high quality factor and high power capacity has been widely used due to its excellent performance, but its size and volume are too large to be suitable for occasions with high miniaturization and integration; while traditional microstrip Although the radiation of the structure is large, due to its small size and simple processing, it can meet the ...

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Problems solved by technology

[0004] Therefore, based on the above-mentioned superior performance of HMSIW, many research institutions and scholars at home and abroad have carried out research on HMSIW bandpass filters in recent years. According to "Zhang, Q.L., Wang, B.Z., Zhao, D.S., and Wu, K.: ACompact Half-Mode Substrate Integrated Waveguide Bandpass Filter With WideOut-of-Band Rejection, IEEE Microw.Wirel.Compon.Lett., 2016, 26, (7), pp.501-503 "proposed based on electromagnetic bandgap (EBG ) structure of the left-handed half-mode substrate integrated waveguide bandpass filter, the filter introduces a transmission zero point at the low frequency of the passband by loading an electromagnetic bandgap structure on the left-handed half-mode substrate integrated waveguide structure, and expands the stopband range. However, the filter bandwidth is narrow and the square coefficient is poor

According to "Huang, Y.m., Shao, Z.H., Jiang, W., Huang, T., and Wang, G.A.,: Half-mode substrate integrated waveguide bandpass filter loaded with horizontal–asymmetrical stepped-impedance complementary split-ring resonators, Electron. Lett. ,2016,52,(12),pp.1034-1036" proposed a half-mode substrate-integrated waveguide bandpass filter based on the ladder impedance-complementary split resonator structure, which combines the traditional ladder impedance structure ( SI) combined with the traditional complementary split resonant ring (CSRR), can effectively increase the equivalent inductance and capacitance of CSRR, thereby reducing the resonant frequency of the filter, but the filter has poor out-of-band rejection and narrow bandwidth

[0005] In summary, loading traditional structures such as complementary split resonator rings, defect grounds (DGS), and electromagnetic bandgap on half-mode substrate-integrated waveguide structures can realize different types of filters. A passband is generated nearby, but there is no transmission zero point or only one transmission zero point at the high and low frequencies of the generated passband. Therefore, the half-mode substrate integrated waveguide bandpass filter based on the traditional structure design has a narrow bandwidth and out-of-band frequency selection Poor performance, large insertion loss, etc.

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