Beam-Reconfigurable Antenna with Inductive Partially Reflective Surface and Parasitic Elements

 A reconfigurable partially reflective surface (PRS) antenna can offer low-cost and low-complexity beam steering, traditionally implemented using a phased array with a bulky feeding network. This paper utilizes ray-tracing to prove analytically that an inductive nonuniform PRS facilitates larger beam deflection and lower sidelobe level (SLL) than a capacitive one, given the same reflection phase difference. With a suitable tradeoff in the beam deflection angle and gain variation between the reconfigurable states, an inductive reconfigurable PRS is designed for a ±13° steering range. To enhance the steering range with minimal complexity, two parasitic elements loaded with PIN diodes are added to the feeding source, resulting in the overall steering range of ±30°. The fabricated prototype verified that the pencil-shape beam can be steered towards 0º and ±30º with SLLs of less than -19dB at 5.5GHz. The antenna achieved peak realized gains of 9.5-10.4dBi for the three states with gain variation of less than 0.9dBi. The measured overlapped impedance band covers 5.41-5.63 GHz for all states.