Compact monopole-like slot antenna and band-notched design for ultrawideband applications

A compact monopole-like slot antenna and its extended band-notched design are presented for ultrawideband (UWB) applications. The proposed antenna is etched on a printed circuit board and fed by a microstrip fork-shaped feeding stub. The characteristics of the proposed antenna are investigated numerically and validated experimentally. The prototype with an overall size of 25 mm x 25 mm x 0.8 mm achieves good impedance matching, constant gain, stable radiation patterns, and consistent group delay over an operating bandwidth of 3.0-12.9 GHz (124.5%). In addition, the proposed antenna features less ground plane dependence. By adding two grounded open-circuited stubs, the proposed antenna features band-notched characteristics at 5-6 GHz while it maintains the desirable performance over lower/upper UWB bands of 3.1-4.8 GHz/6.2-9.7 GHz.