A reconfigurable microstrip cross parasitic antenna with complete azimuthal beam scanning and tunable beamwidth

Abstract

In this article, a reconfigurable cross parasitic antenna is proposed to achieve complete azimuthal beam scanning and tunable beamwidth in the E- and H-plane. The antenna consists of a square-shaped driven element and four size-tunable parasitic elements placed on each side of the driven element. Each tunable parasitic element is composed of a hexagonal slot loaded with two varactor diodes. The tunable parasitic element shows dual-resonance behavior and hence its effective electrical size can be controlled with respect to the driven element. The radiated beam of the cross antenna is continuously scanned in the elevation plane from θ = 0° to 10.8°, 0° to 32.4°, and 0° to 40° in ϕ = (0°, 180°), (45°, 135°, 225°, 315°), and (90°, 270°) planes, respectively. Moreover, the 3-dB beamwidth of the cross antenna is continuously tuned from 65° to 152° and from 64° to 116° in the E- and H-plane, respectively. The antenna shows good impedance matching in all the operating modes with −10 dB bandwidth from 2.43 to 2.47 GHz. A prototype of the antenna is fabricated to experimentally verify the simulated reflection and radiation characteristics.