Bandwidth Enhancement of Printed E-Shaped Slot Antennas Fed by CPW and Microstrip Line

Two printed wide-slot antennas with E-shaped patches and slots, for broadband applications, are proposed. They are fed by a coplanar waveguide (CPW) and a microstrip line with almost the same performances. Detailed simulation and experimental investigations are conducted to understand their behaviors and optimize for broadband operation. Good agreement between the measurement and simulation has been achieved. The impedance bandwidths, determined by 10-dB reflection coefficient, of the proposed slot antennas fed by microstrip line and CPW, from both measurement and simulation, are about 136% (2.85 to 15.12 GHz) and 146% (2.83 to 18.2 GHz), respectively. This large operating bandwidth is obtained by choosing suitable combinations of feed and slot shapes. In order to achieve wider operation bandwidth both of the designed antennas have round corners on the wide slot and patch. Meanwhile, the proposed antennas exhibit almost omnidirectional radiation patterns, relatively high gain, and low cross polarization. A comprehensive numerical sensitivity analysis has been done to understand the effects of various dimensional parameters and to optimize the performance of the designed antennas. Results for reflection coefficient, far-field E and H-plane radiation patterns, and gain of the designed antennas are presented and discussed.