A Collimated Surface-Wave-Excited High-Impedance Surface Leaky-Wave Antenna

This letter presents a novel high-impedance surface (HIS)-based leaky-wave antenna excited by collimated surface wave (SW). The proposed antenna consists of two identical SW launchers (SWLs) and an HIS structure. Regarding the SWL, it is based on an offset-fed parabolic reflector. By using the substrate-integrated waveguide technique, the reflector system is integrated in the planar substrate. For the HIS, it is formed by a periodically arranged rectangular microstrip patch array. The proposed SWL can generate collimated SW with the TM0 propagation mode. With the perturbation of the HIS, the guided SW can be transformed to m = -1 space-harmonic-mode leaky wave. In addition, in order to obtain efficient broadside radiation, an additional secondary slit is properly designed in each unit cell of the HIS to suppress the open-stopband effect. A prototype of the proposed antenna is demonstrated by both full-wave simulation and experimental verification. Continuous beam scan can be realized from -36 degrees to + 35.5 degrees within the frequency range of 16-22 GHz.