A compact size 2.9-23.5 GHz microstrip patch antenna with WLAN band-rejection

This article presents the design and realization of a compact ultra-wideband (UWB) antenna with on-demand WLAN band-rejection. The antenna consists of a simple truncated rectangular patch with a U-slot and a partial ground plane, which are both patterned on Taconic TLY-5 substrate (epsilon(r) = 2.2). The lower corners of the patch are truncated with a semicircle to realize wideband characteristic, while the notch is obtained by etching a U-slot on the radiating patch. The proposed antenna outperforms the existing UWB antennas owing to its compact size, radiation stability, and very wide impedance bandwidth. Simulated and measured results show that the novel antenna has a very wide operating bandwidth of 2.9-23.5 GHz with a VSWR <2, and a notch band from 4.9 to 6.1 GHz to reject IEEE 802.11a and HIPERLAN/2 frequency band. The antenna offers promising performances including moderate gain (G(max) = 6.1 dB), nearly omnidirectional stable radiation patterns, and a compact overall size of 13x22x 0.8 mm(3). Besides of the other advantages, this antenna design presents mechanical robustness, easy integration into circuit boards, and excellent low-cost mass production suitability.