A low loss and self-packaged patch coupler based on SISL platform

Abstract

This paper proposes a low loss and self-packaged patch coupler based on substrate integrated suspended line (SISL) platform. Due to the benefit of self-packaging, the radiation loss of the patch can be reduced to the minimum. By cutting out the substrate as much as possible while ensuring mechanical strength, the dielectric loss will be further reduced. By connecting the metal layers on both sides of the substrate with via holes, the conductor loss can be further reduced. The measurement and the simulation results of the fabricated SISL patch coupler at 6 GHz are well agreed. The measured insertion loss is only around 0.15 dB. From 5.5 GHz to 6.6 GHz, the measured phase imbalance is 90°±1° and the measured amplitude imbalance is smaller than 0.6 dB. The measured loss is much smaller than that of the previous designs.