A Compact Surface Wave Launcher with Higher Directivity for Leaky Wave Antenna of Producing Hologram

Holographic antenna have many advantages including independent frequency, low profile and multiple functions. Planer holographic antenna can be designed with leaky wave antenna with surface wave launcher (SWL) fed by a single-plane coplanar waveguide as the feed source. This paper presents a compact surface wave launcher design with higher directivity. To optimize parameters of the launcher, gain of the antenna with proposed SWL-fed-structure is maximized. The directivity of SWL, which can be defined as forward-backward coupling ratio, is reported to reach a peak of 36.58 dB at 25.27 GHz. Moreover, sphere-like overall phase distribution and less amplitude distribution at substrate’s edges of the electric field are both reported, which can enhance the efficiency of holographic antenna.