Research on the 2-D annular leaky-wave antenna

This paper studies a 2-D planar periodic leaky-wave antenna based on a series of concentric annular microstrip rings on a grounded dielectric slab. The leaky wave is generated from the perturbation to the surface wave, which is excited from the fundamental and dominant TM0 mode. The computation method for the propagation constant is first analyzed, and then the radiation property is researched. A set of suitable structural parameters for only -1th spacial harmonic radiation are extracted from the theoretical computation and then verified by the simulation, which shows an agreement. The results indicate that this proposed antenna can radiate two symmetrical flat conical beams with over 90% total efficiency. The theoretical results on radiation performance are then verified by simulation and measurement with good agreement.