Spoof surface plasmon polaritons based microwave bandpass filter

Recently, Plasmonics and metamaterials have been receiving consideration. Spoof surface plasmon polaritons (SSPPs) are a type of electromagnetic surface wave that to a certain limit shares an analogous behavior with surface plasmon polariton (SPP) at microwave frequency domain. The significant point is that the dispersion relation of SSPP is principally controlled by the geometry of the pattern using plasmonic metamaterial. The motivation behind this work is to explore and implement the subwavelength propagation or nanoconfinement of wave beyond the diffraction limit using plasmonic metamaterial‐inspired SSPP structure in the microwave frequency domain. In this article, the conventional symmetric H‐shaped unit cell is modified into a new unit cell. Using this modified unit cell, a new SSPP structure is designed which provides broadband bandpass filter (BPF) characteristics. The measurement shows the passband of BPF is 1.2 to 6.0 GHz with insertion loss less than 2 dB. The size of the fabricated SSPP BPF is 26 × 4 cm.