A 6–18 GHz cavity-backed log-periodic-slot end-fire antenna for conformal application

A 6-18 GHz log-periodic slot-inspired cavity-backed end-fire antenna for conformal application is proposed in this paper. The log-periodic structure with 10 slot elements is applied to cover 6-18 GHz frequency band and the metallic cavity is placed under each slot element to keep wideband performance and prevent the effects of large metallic holder on the radiation pattern. A dielectric cover is used to improve the antenna performance and a broadband microstrip-CPW transition are inserted in the antenna as the feeding network. With these novel designs, the proposed antenna shows experimentally a good return loss and end-fire gain performances in the frequency range of 6-18 GHz. The proposed antenna also keeps low-profile and easy flush-mounted characteristics.