A compact triple-frequency CPW-fed planar monopole antenna for PCS/WiMAX/WLAN applications

A triple-frequency compact monopole antenna with coplanar waveguide (CPW)-fed structure is presented in this paper for PCS 1900, WiMAX and WLAN applications. The proposed antenna, which consists of a rectangular radiation patch with L-shaped slot and an inverted L-shaped stub extending from the ground plane. By engraving an L-shaped slot on the rectangular radiation patch, the antenna can excite two resonant modes (WiMAX and WLAN). The third resonant mode is introduced by extending an inverted L-shaped stub from the ground plane (PCS 1900). The designed planar monopole antenna has a compact size of only 17×30×1 mm³ including the ground plane. The simulated -10dB impedance bandwidth at the first band (lower frequency, fr₁=1.91 GHz) is about 180 MHz, for the second band (middle frequency, fr₂=3.52 GHz) is about 650 MHz and at the third band (upper frequency, fr₃=5.45 GHz) reaches about 1.45 GHz, which cover the PCS 1900 standards (from 1.85 to 1.99 GHz), the 3.5/5.5 GHz WiMAX standards and the IEEE 802.11a 5.2/5.8GHz WLAN standards, respectively. Furthermore, nearly omnidirectional radiation patterns, reflection coefficient and gain over the operating bands have been obtained.