CPW-fed ultra wideband (UWB) monopoles with band rejection characteristic on ultra thin organic substrate

Two CPW-fed compact elliptical monopole UWB antennas are introduced with band rejection characteristic at the band used for wireless LAN applications. The antennas are fabricated on ultra thin (100 mum) liquid crystal polymer (LCP) and the band notch is caused by the presence of a resonating slot within the elliptical radiator. The two investigated antennas have a U-shaped slot and a C-shaped slot respectively. From the presented return loss and VSWR measurements, the C-shaped slot causes a wider rejection band compared to the U-shaped slot that could be used for the design of UWB antennas with reconfigurable sub bands. Both designs present almost identical radiation pattern behavior with the design without any slot with the exemption of the gain in the frequency notch band, which is maintained negative.