Low-loss BiCMOS spoof surface plasmon polariton transmission line in sub-THz regime

Abstract

This study presents an on-chip spoof surface plasmonic polariton transmission line (sSPP-TL) in the sub-THz regime. The proposed sSPP-TL is designed and fabricated in the standard 0.13 μm BiCMOS process. To eliminate the influence of a high index silicon substrate, a special underlying ground shielding plane is introduced. A mode converter is designed with both impedance and momentum matching in order to achieve efficient conversion from grounded coplanar waveguide to sSPP-TL. Electromagnetic (EM) simulated and measured results show good conversion efficiency from quasi-transverse EM to sSPP mode (measured input reflection coefficient is below -18.5 dB). More importantly, a low propagation loss profile (average measured insertion loss is 1.54 dB/mm) is observed in the broadband frequency range in sub-THz (140-325 GHz). The demonstrated sSPP-TL has shown great potential for on-chip sub-THz communication in the standard silicon process.