A quasi-elliptic Band Pass Filter designed using quadruplet metamaterial resonators for operation in the 3 GHz (5G) Band

Abstract

In this paper, we investigate the pertinent characteristics of a metamaterial square spiral resonator in realizing a compact bandpass filter operating in the 3.5-3.7 GHz 5G band. The resonators designed by analytical modelling and full wave simulations are incorporated as broad side coupled structures between two parallel input and output microstrip lines. By incorporating radial stubs in the microstrip line, the stop band performance of the filter is improved approximately up to three times the operating frequency. It exhibits competitive attenuation slopes of 79.4 and 67.46 dB/GHz in the lower and upper pass band edges respectively. Electrical size of the proposed filter is just 0.44 × 0.44 $\lambda _g^2$. Operating frequency of the filter can be easily tuned by redesigning the resonators with the design guidelines presented in this article. The proposed filter uses no grounded structures, vias, defected ground or multilayer structures, and hence can be easily fabricated and integrated to microwave circuitry.