A simple circularly-polarized traveling-wave array antenna

This paper presents a simple circularly-polarized traveling-wave array antenna. It uses four identical rectangular microstrip patches which are arranged in two rows of two elements to form the array. Fairly low cross-polarization radiation is achieved by exciting the two rows of traveling wave arrays with opposite feed locations and opposite phases. Measured results show that the 3-dB axial ratio bandwidth for both RHCP and LHCP is 11.5%, a peak gain of 14 dBi is achieved, low side lobe levels and a 15-dB cross-polarization discrimination at beam peak. Measured performance is presented.