Abstract – Different fractal geometries are successfully applied to design compact size printed and microstrip antenna structures for multiband and dual-band wireless communication applications. In this paper, a printed antenna with fractal based slot structure is presented as a candidate for use in dual-band wireless applications. The slot structure of the proposed antenna is with circle based fractal geometry. The slot structure has been etched in the ground plane of an FR4 substrate with relative dielectric constant of 4.4 and 1.6 mm thickness and on the reverse side a microstrip line has to be printed as a 50 Ω feed. Simulation results of the modeled antenna show that it offers a dual-band resonant behavior with a considerable resonant frequency ratio; covering a wide variety of wireless applications. Modeling and performance evaluation of the resulting antenna are carried out using the commercially available EM simulator HFSS, from Ansoft Corporation. A parametric study reveals that the proposed antenna offers fractional bandwidths of about 13% to 27% for the lower resonant band and 7% to 28% for the upper resonant band. The corresponding gain throughout these bands varies from 2.53 to 3.58 dB and from 4.08 to 5.76 dB respectively. This makes the antenna suitable for use in a wide variety of wireless applications. A fabricated prototype of the proposed antenna shows a return loss response which is in reasonable agreement with that theoretically predicted within the same swept frequency range. Furthermore, the proposed antenna exhibits good radiation characteristics at the resonant bands.
Keywords – Fractal antenna; slot antenna; dual-band antenna; printed antenna; circle-based fractal geometry.