Design and Simulation of a Miniaturized Printed Wideband Antenna with a Gradual Radiator and Defected Ground

Abstract

To improve the integration capability and impedance matching of printed antennas for wideband wireless terminals, a miniaturized planar antenna with a gradual radiator and a defected partial ground is designed and verified by full-wave simulation. The antenna is implemented on an FR4 substrate of 31 mm x 18 mm x 1 mm and fed by a 50 Ohm microstrip line. A gradual, chamfered radiator with a top arc and T-shaped loading is combined with a partial ground containing a central slot and tapered edge, so that the forward and return current paths can be tuned simultaneously. The Driven Modal solver in Ansys HFSS is used to evaluate the reflection coefficient, field, and current distributions, and far-field radiation. The simulated S11 curve exhibits resonances near 3.3 GHz, 4.4-4.6 GHz, 7.7-8.0 GHz, and 13.0 GHz; the deepest resonance reaches about -35 dB, and the typical peak GainTotal is about 3.2 dBi. A parameter sweep of La from 0.6 mm to 0.8 mm shows little influence on the main resonances. The results indicate that the proposed structure provides a compact and feasible basis for multi-band or wideband terminal antennas.