Generating a Reconfigurable Notch Band for Planar UWB Monopole Antennas

A technique to generate a reconfigurable notch band for planar ultrawideband (UWB) monopole antennas with microstrip-fed is proposed and studied. The antenna uses an elliptical radiator with a tapered microstrip feed line to achieve a wide bandwidth from 3.1 to over 10.6 GHz. A resonator implemented using meander-defected-ground structure (meander-DGS) is etched on the ground plane to generate a notch band to suppress unwanted interference in the frequency band of 5.15–5.825 GHz from the unwanted IEEE 802.11a/n wireless-local-area-network (WLAN) systems. To achieve tunability for the notch band, a varactor is loaded on the DGS to control the resonance frequency. The tuning performance, in terms of reflection coefficient, radiation pattern, efficiency and gain, of the antenna is studied using simulation and measurement. Results show that the notch band can be tuned continuously from 5.2 to 6.32 GHz for the WLAN bands. The feeding cable used in measurement causes substantial discrepancies between the simulated and measured results. To study the cable effects, a simulation model for the feeding cable is included to simulation. With the use of the cable model, the simulated and measured results agree very well. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2906–2910, 2013