A ultrawideband antenna with dual-band band-notch filters

The heptagonal-shaped monopole antenna design for ultrawideband (UWB) applications is proposed. This antenna is designed on PCB FR4 substrate with relative permittivity (r)=4.4, loss tangent tan=0.0245, and thickness h=1.6 mm. The antenna consists of a radiated patch, a feed line, and a ground plane. With the different geometrical parameters, simulated and experimental results of the antenna are suitable for UWB operations. The bandwidth VSWR<2 of the UWB antennas from measurement is approximate to 122.02% (2.63-10.86 GHz). To decrease the interference with the wireless local area networks (WLANs) at 5.2/5.8 GHz and worldwide interoperability for microwave access (WiMAX) at 3.5/5.5 GHz, two band-notched filters covering from 3.4 to 3.69 and 5.15 to 5.85 GHz was design. Two L-shaped slots on the patch and two slot-type split ring resonators (SRRs) on the ground plane were used to produce two band-notched frequency bands. The results for VSWR, far-field H- and E-plane radiation patterns and gain of the proposed antennas are presented and discussed. The radiation area of the design antenna is 26 x 16.38 mm(2). The measured results show a good agreement with the simulated results.