Millimetre Wave Filters Based On Split Ring Resonators

With the rapid development of the microwave communication system,the electromagnetic spectrum resource in the low frequency section becomes more and more tense,and the demand for the communication equipment is more and more stringent.Therefore,the research of the high frequency communication equipment including the millimeter wave and the terahertz wave is very promising.This paper mainly studies the design of the filters in millimeter wave.The left handed material,including the split ring resonator(SRR),has been widely used in the design of the millimeter wave filter as a new material.The filter which combines the split ring resonator with the transmission line and the resonant cavity can improves its performance and realize the miniaturization of the device.In this paper,the millimeter wave filters with excellent performance based on the split ring resonator and complementary triangular split ring resonator(CTSRR)are proposed.In this paper,a coplanar waveguide(CPW)bandpass filter based on a novel SRR is proposed.According to the characteristics of the traditional SRR,a novel SRR structure is proposed.The metallic via-hole is used to connect the SRR etched on the back of the CPW with the ground plate.Thus a bandpass filter with good performance is obtained.Substrate integrated waveguide(SIW)technology has attracted much attention due to its advantages of high quality factor,considerable power,low insertion loss and low cost.In this paper,a bandpass filter with triangular substrate integrated waveguide(TSIW)based on CTSRR is proposed.A pair of metallic via-holes is added to separate the degenerate mode and adjust the transmission zeros.Meanwhile,the CTSRR is utilized as a resonator to work together with the degenerate modes.Finally,a 16% 3dB-fractional bandwidth bandpass filter with three transmission zeros is designed.In addition,based on the TSIW cavity above,a TSIW dual-band filter based on CTSRR is proposed.The two passbands are realized by the CTSRR and the degenerate modes.In order to control the transmission zeros,two adjustment techniques include shifting feeding technique and adding via perturbations are introduced.Finally,the dual-band filter with transmission zeros in both sides of each passband is designed.The filters based on TSIW are fabricated and measured.And the measured results are in agreement with the simulation results.It also proves that the designed filters are feasible in engineering.