A Compact Integrated UWB/Reconfigurable Microstrip Antenna for Interweave Cognitive Radio Applications

摘要

This paper presents a compact sensing/communicating antenna configuration for interweave cognitive radio (CR) systems. The sensing antenna is an ultra-wide band (UWB) planar monopole antenna, while the communicating antenna is a reconfigurable microstrip antenna etched on the backside of the UWB antenna radiating patch. Based on the current distribution of the UWB sensing antenna, the position and the shape of the communicating antenna are optimized to effectively reduce the mutual coupling between the antenna ports. A frequency reconfigurability from (5-6) GHz is achieved by attaching a varactor diode to the radiating patch of the communicating antenna. The simulated and measured results show good radiation and frequency domain characteristics of the proposed antenna. It is found that the communicating antenna has reflection coefficient values less than -18dB at the resonant frequencies. The mutual coupling between the sensing and communicating antennas is found less than -20dB.