Four-element planar array antenna for UWB application

A novel low-cost 4-element planar array antenna directly fed by a coaxial cable for Ultrawideband (UWB) application is presented. The proposed antenna consists of 2*2 bowtie elements and a simple 1*4 power divider feeding network. Comparing with the basic bowtie element, the impedance bandwidth of the array antenna has a significant improvement that the low cut-off frequency is extended from 6GHz of the bowtie element to 2GHz. The measured results show that the antenna has a bandwidth of 2GHz to 11GHz for VSWR<;2. The proposed antenna exhibits a bidirectional radiation pattern and a modest gain across the operating band and a peak gain of about 9 dBi at 11 GHz.