Design of Monopole Antenna with Defected Ground for WLAN Application

In this paper, a dual-band monopole antenna is proposed for wireless local area network (WLAN) application. The antenna consists of rectangular ring with two slots and defected ground plane, due to which two resonant modes are generated to cover 2.7 and 5.5 GHz WLAN bands. The antenna is fed by 50 Omega microstrip lines. The overall dimensionof the antenna is 20x25x0.8mm(3). The designed antenna operates over the frequency ranges from 2.1-2.84 GHz and 5.1-5.89 GHz with <=-10 dB return loss which is suitable for WLAN bands. The Radiation pattern, peak realized gain, radiation efficiency and current distribution are used to analyze the radiation characteristics of the antenna. Theradiation pattern of the proposed antenna is omnidirectional. The peak realized gain of the antenna is 2.00 dBi at 2.7 GHz band and 3.25 dBi at 5.5 GHz band and the radiation efficiency is 90.29% at 2.7 GHz band and 88.98% at 5.5 GHz band respectively.