Design and Implementation of a Dual Antenna for Cognitive Radio Systems

The cognitive radio (CR) system optimizes spectrum usage and enhances transmission efficiency by automatically adjusting parameters to adapt to changing environments. Antennas in cognitive radio systems are crucial because they must be reconfigurable to operate across different frequency bands, optimizing spectrum usage and improving transmission performance. This paper proposes a dual antenna for cognitive radio systems, consisting of a UWB (Ultra-Wideband) antenna and a frequency-reconfigurable narrowband antenna. The UWB antenna is designed to cover an ultra-wideband range from 2.14 to 14.9 GHz for spectrum sensing, and the frequency-reconfigurable narrowband antenna is designed for communication. A set of 6 PIN diodes is used to change the electrical length, allowing the antenna to switch frequencies among 2.42, 4.95, 5.13, 5.21, 5.38, 5.5, 5.7, and 5.95 GHz, corresponding to the frequency bands of WiFi, WiMAX, and WLAN. Its compact size of 30×70×1.6 mm3 makes it easy and convenient to install in terminal devices.