Low-loss microwave cavity using layered-dielectric materials

Loss measurements have been carried out on a cylindrical pillbox cavity whose metallic flat end walls have been replaced by an ordered sequence of high purity sapphire and air dielectric layers. The loss of the TE01 mode at 18.99 GHz was substantially lowered. An improvement in cavity Q for this mode from 8.30×103 to 531×103 was observed. These experimental results closely reproduce two independent theoretical simulations. All measurements were taken at 30 °C.