Investigation of Low-loss COC Dielectric Substrate on Leaky-wave Antenna at Millimeter-wave Band

This article investigates the effect of low-loss cyclic olefin copolymer (COC) dielectric substrate on the performance of millimeter-wave devices. As a proof of concept, a circularly polarized leaky-wave antenna working at Ka band based on spoof surface plasmon polaritons (SSPPs) is designed and optimized, by the use of low-loss COC substrate. By taking different values of substrate dielectric loss tangent, the simulated results verify that low-loss dielectric substrate such as COC (assuming its dielectric loss tangent at Ka band is 0.001) would greatly improve the performance of leaky-wave antennas at millimeter-wave band. The proposed leaky-wave antenna has a high gain of 9.3 dB and radiation efficiency of 91% at 26.5 GHz, which is 1.21 dB and 20%, 11.05 dB and 79% larger when the loss tangent of dielectric substrate increases to 0.01 and 0.1, respectively.