A modified rectangular monopole antenna with defected ground structure & slot in the feed-line for cognitive radio applications

Design of antenna for cognitive radio application is proposed in this paper. A novel antenna is presented here with the rectangular monopole modified by rounding the edges to improve the performance of antenna which serves as the sensing antenna for cognitive radio and the desired frequency reconfiguration for the communicating antenna is provided by defected ground structure and the slot in the feed-line with switches. A prototype of the antenna is fabricated and tested. A good agreement is found between the simulated and measured data.