Compact and high-performance lowpass filter based on surface plasmonic polaritons waveguide

Abstract

Abstract A terahertz spoof surface plasmonic polaritons waveguide with metallic rectangular spiral is proposed in the paper. By analyzing dispersion relation and electric field distribution, it is found that the proposed waveguide has a lower asymptotic frequency, a tighter localized field with 11.7 times enhancement, and a more compact size compared with the T-grooves waveguide. Based on a rectangular spiral waveguide structure, a compact and very sharp roll-off lowpass filter is investigated and experimentally verified by scaling down frequency to the microwave region. The fabricated lowpass filter has a high roll-off rate of 566 dB GHz−1, ultrahigh figure-of-merit of 43039, and compact size. Therefore, it may be applicable for various compact integrated devices and circuits in THz and microwave frequency ranges.