Double balanced multiplier integrated circular polarization switchable microstrip antenna

In this paper, a circular polarization switchable microstrip antenna with a double balanced multiplier that consists of four diodes in a star form is proposed. A 90 deg. phase difference condition of two orthogonal excitation modes on a patch is produced by a didoes' nonlinear coupling of the multiplier. A circular polarization switching (LHCP and RHCP) capability by a bias polarity for diodes is experimentally confirmed.