Impedance bandwidth improvement for microstrip-fed slot antennas using short-circuited termination

In this paper, the impedance bandwidth of microstrip-fed slot antennas is improved by using short-circuited termination as compared to open-circuited termination. The bandwidth improvements for simple slot, single-folded slot, and double-folded slot antennas, respectively, are demonstrated. The 10-dB return loss bandwidth of 29% is attained for the double-folded slot antenna fed by a short-circuited microstrip line. The measured far-field patterns are stable across the passband, which makes it a good candidate for UWB application.