Design of Frequency Reconfigurable Patch Antenna for Sensing and Tracking Communications

Abstract

This paper presents a front-end structure of a reconfigurable patch antenna for cognitive radio systems. The antenna structure consists of an Ultrawideband (UWB) sensing antenna and an array of frequency reconfigurable antennas incorporated on the same substrate. The UWB and reconfigurable antennas are fed by co-planar waveguides (CPW). The reconfigurability is achieved by rotating the series of patch antennas through a certain angle and the rotation is controlled by mechanical means using an Arduino microcontroller. The rotational reconfigurability has been preferred over MEMS switches, PIN diodes, and other lumped elements because the latter requires the need for bias lines. The entire structure is designed using High Frequency Structure Simulator (HFSS) software and the prototype is fabricated over FR-4 substrate having a thickness of 1.6mm and measurements are carried out. This antenna achieves a wideband frequency from 2 GHz to 12 GHz and distinct narrow band of frequencies by reconfigurability using single antenna consisting of different shapes spaced accurately to ensure isolation between adjacent frequency bands and each antenna element working for a bandwidth of 2 GHz for frequency from 2 GHz to 12 GHz upon a single substrate and the reconfigurable elements are controlled using a low cost Arduino microcontroller connected directly to the antenna which ensures accurate controlling of the rotation and fast switching between the antenna elements. The measured results agree with the simulated results and have less than 10 dB impedance bandwidth.