Abstract: This paper presents the design of microstrip rectangular patch antenna with center frequency at 3.8 & 5GHz for WiMAX & WLAN application. The antenna with microstrip line feeding technique was designed and simulated using Computer Simulation Tool (CST) Microwave Environment software. The antenna designed on Roger4004substrate with overall size of 30x40 x 1.59 mm3 and dielectric substrate with e_r = 4.4. This antenna structure isdesigned by using CST Software based on the characteristic impedance for the transmission line model. The performances of designed antenna are compared in terms of parameters like substrate dimension, feed size and ground plane. The antenna performance in terms of its frequency domain and time domain characteristics are investigated.

Keywords: CST Microwave Studio, UWB, WiFi, WiMax, Simulation, Microstrip Line Feed, microstrip Antenna, Omni-directional patterns.