Impedance characteristics of trapezoidal ultra-wideband antennas with a notch function

In this paper, we propose trapezoidal ultra-wideband (UWB) antennas that have a notch function. The proposed antennas cover the entire UWB band (3.1-10.6 GHz) and have a notch for the IEEE 802.11a frequency band (5.15-5.825 GHz) by varying the shape of the slot inserted into the antenna. To obtain a frequency-notched UWB antenna. we incorporate slots of various shapes into the antenna. The notch frequency can be adjusted by changing the slot length. The proposed antennas also show good gain flatness, except in the IEEE 802.11a frequency band. (c) 2005 Wiley Periodicals, Inc.