Millimeter-Wave On-Chip Bandpass Filter Based on Spoof Surface Plasmon Polaritons

A gallium arsenide (GaAs)-based millimeter-wave broadband bandpass filter (BPF) is proposed based on slotted half-mode substrate integrated waveguide (HMSIW) spoof surface plasmon polaritons (SSPPs). The center frequency and bandwidth of this SSPP-based on-chip BPF can be easily controlled by tuning the geometry dimensions of the SSPP unit cell, which is attributed to its unique dispersion characteristics. For demonstration, a prototype of the proposed BPF is fabricated and experimentally characterized, with good agreement between the simulated and measured results. Due to the ability of the strong electric field confinement, the proposed on-chip SSPP structure has lower coupling feature with closely-spaced transmission line circuits than its counterpart traditional HMSIW structure.