Continuous Beam Steerable Parasitic Antenna Array

Abstract

This paper proposes a parasitic antenna array for continuous beam steering at 900 MHz. Pattern reconfigurable or beam steerable antenna is in demand nowadays especially for wireless systems such as wireless power transfer (WPT) system. Various research has been conducted to improve the reliability of WPT due to its ability to overcome the drawbacks of conventional power supply such as battery that has limited lifetime and wire or cable that might break. Hence, an effective power transfer is desired for power to be supply sufficiently. This can be achieved by implying a directive and steerable antenna to the system. Incorporation of varactor diode on parasitic antenna array is able to attain these properties. The designed antenna in this study consists of 3 layers; (1) a driven element and parasitic stubs, (2) four parasitic dipoles and two shorted dipoles, (3) two parasitic dipoles. FEKO software is used to design and simulate the proposed antenna array. Each parasitic dipole is loaded with varactor diodes in order to control the capacitance. By varying the capacitance at appropriate parasitic dipoles, the beam can be steered from 0° to 80° with 5° steps in the azimuthal plane. The peak gain of the array approximately around 7.5 dBi, while the beamwidth range from 64° to 93°.