A Compact Two-Port Integrated UWB and Frequency Reconfigurable Antenna System for Cognitive Radio Application

A compact antenna system of two-port integrated UWB monopole antenna and frequency reconfigurable slot antenna for cognitive radio application is proposed. The antenna structure consists of a UWB monopole antenna and a frequency reconfigurable antenna. The UWB monopole antenna is designed to cover the entire UWB spectrum of 3.1-10.6GHz for spectrum sensing, and the frequency reconfigurable antenna is designed for communication. The antenna size is 40mm×26mm×0.8mm. The frequency reconfigurable antenna is a slot controlled by varectors to change the electrical length, and it can realize frequency switching between 5.2GHz, 5.5GHz and 5.8GHz, corresponding to frequency bands of WiMAX and WLAN. The frequency reconfigurable antenna is embedded in UWB monopole antenna and the isolation between them is larger than 15dB.