DESIGN AND PERFORMANCE ANALYSIS OF AN ANTENNA WITH DEFECTED GROUND STRUCTURE FOR COGNITIVE RADIO APPLICATIONS

With development of communication technology, size reduction of microstrip antenna is becoming an important design consideration for practical applications. So, a microstrip-feed circular monopole antenna (CMA) with defected ground structure is proposed for cognitive radio applications, which is modified further to reduce the dimensions of the patch for comparatively lower frequencies. The design considerations for achieving wideband and reconfiguration of the proposed antenna are also discussed. Most of the work in cognitive radio domain has been done in the frequency range of 3.1GHz to 10.6 GHz, but this paper presents a Circular Monopole Antenna (CMA) operating over frequency band of 0.6GHz to 3.58GHz. The proposed antenna was designed and analyzed by using software HFSS (High frequency structure Simulator) 13.0. The proposed antenna uses FR-4 substrate having thickness of 1.6mm and dielectric constant of 4.4. This antenna achieves an impedance bandwidth of 2.98GHz. Antenna performance parameters such as antenna gain, return loss, VSWR, Input impedance, reflection coefficient over the operating bands have been observed and found to be well within the desired range. The simulated results of the proposed design found in close conformity with the measured results of its fabricated counterpart.