A circularly polarized loop antenna without perturbation segments

A loop antenna using an L-shaped wire for the feed has been numerically investigated. Calculations reveal that the antenna radiates a CP beam with an axial ratio of 0.1 dB, when the L-shaped wire is shifted by d = 0.1 Oλ₀. To know the radiation mechanism, the current distribution is presented and the total radiation from the antenna is decomposed into radiation from the L-shaped wire and radiation from the loop proper. It is found that the CP beam is formed mainly by the loop proper along which a traveling-wave type current is distributed.