A stair-shaped CPW-fed printed UWB antenna for wireless body area network

In this paper, a CPW-fed ultra-wideband antenna for wireless body area network is proposed. The proposed antenna has a stair-shaped structure printed on the top of a substrate with the dielectric constant of 4.4 and occupies a small volume of 36 mm × 24 mm × 1 mm. The antenna has an impedance bandwidth of 8 GHz from 3 to 11 GHz. The variation of group delay between the two proposed antennas is less than 1.09 ns and the maximum gain variation is about 6.5 dB. The radiation pattern over the frequency band of interest is changed from near omni-directional to directional pattern when the antenna is placed on the body.