A Wideband Printed Quadruple-Element Antenna With Integrated Balun

A printed ultrawideband (UWB) unidirectional quadruple element antenna is presented. The antenna is composed of four radiating elements with corrugated boundaries and a microstrip-to-double-sided parallel-strip line transition. The antenna size is 0.285λ_L × 0.285λ_L × 0.174λ_L at the lower operating frequency. Experimental results reveal that it can achieve an impedance bandwidth of 83.7% for VSWR <; 2 and a stable unidirectional radiation pattern with measured gain around 6.7 dB. Simulated and measured results are given, and they agree well with each other.