Ultra-Wideband and Compact Terahertz Planar Load Based on Spoof Surface Plasmon Polaritons With Nickel

In this brief, an ultra-wideband and compact planar terahertz matching load based on spoof surface plasmon polaritons (SPPs) is proposed. As a result of subwavelength field confinement and huge metallic loss near the cutoff frequency of SPP waveguides, a tapering SPP structure with nickel (Ni) can terminate the circuit with quasi- 50 Ω impedance. The Ni-SPP structure can absorb most of the propagating electromagnetic wave as a matching load. The voltage standing wave ratio (VSWR) of this proposed Ni-SPP load, with half a wavelength in length at 250 GHz, is below 1.2 from 150 GHz to 1000 GHz. In order to demonstrate its feasibility in terahertz circuits, this SPP load is then applied in a conventional two-way power divider working from 220 to 325 GHz. The simulated and experimental results show that it has performance similar to that of an ideal load, indicating that the proposed SPP load could have lots of potential applications in terahertz planar multiple-port circuits.