A Versatile Reconfigurable Antenna for Cognitive Radio

This paper presents a versatile reconfigurable antenna capable of spectrum sensing along with various reconfiguration features. The proposed antenna senses the spectrum by semicircular structure from 3 GHz to 10 GHz to identify the spectrum conditions. After recognizing the spectrum condition, the proposed antenna can reconfigure its polarization state, bandwidth and radiation pattern. Polarization reconfigurability is achieved by using a switchable slot in the circular antenna at 5.1 GHz. Radiation pattern reconfigurability is achieved by shorting the parasitic ring at 7 switchable posts via PIN diodes. Bandwidth reconfigurability is obtained by switching two active ports. Measured and Simulated results of the proposed antenna shows very good agreement, hence, validating the design.