A Reconfigurable Microstrip Leaky-Wave Antenna With a Broadly Steerable Beam

A half-width microstrip leaky-wave antenna with an electronically steerable main beam is introduced. Lumped capacitors are connected between the free edge of the antenna and the ground plane through computer controlled switches, allowing the phase constant of the propagating wave to be varied. Consequently, the main beam of the antenna can be directed along any chosen direction in the longitudinal plane, at any frequency within the operating band of the antenna. By recalling stored switch combinations, the antenna may be steered at a certain frequency, or the antenna may be frequency-scanned while maintaining the beam at a fixed angle. The antenna may also be operated in a dynamic mode using a feedback system, where appropriate switch configurations are determined in real time using an efficient search algorithm. As a proof of concept, simulations are used to determine switch states to allow beam steering through nearly a full 180 degree scan range and also to keep the main beam at a fixed angle across a broad frequency spectrum.