Wideband circularly-polarized loop antenna

A simple loop antenna without loading is introduced to radiate a circularly-polarized wave with a broad bandwidth. This antenna consists of a rhombic loop with one point opened and located above a ground plane. A proposed technique to control the current distribution is (1) to open one point at an appropriate position on the loop and (2) to change the loop configuration. The antenna characteristics including axial ratio, current distribution, radiation pattern and input impedance are calculated by the method of moments. The calculated results are in good agreement with the measured data.<>