Compact CPW-fed antenna with two asymmetric U-shaped strips for UWB communications

A novel coplanar waveguide (CPW)-fed printed antenna with two asymmetric U-shaped strips is designed and analysed for ultra-wideband wireless applications. The asymmetric radiating structure with two U-shaped strips and a staircase-shaped strip is adopted in the proposed antenna which broadens the bandwidth to a great extent. The dimensions of the antenna are only 23 x 25.5 x 1.6 mm. The antenna yields a wide bandwidth ranging from 3.0 to 12.9 GHz with return loss less than -10 dB with near-linear phase characteristics and stable antenna gain. Furthermore, the proposed antenna can achieve quasi-omnidirectional radiation patterns. The measured results agree well with the simulated prediction.