Circularly polarized designs of modified isosceles triangular microstrip antennas

The modified designs of different isosceles triangular microstrip antennas realized by overlapping two isosceles patches, are proposed for circularly polarized response. An offset distance between the two overlapped patches yield optimum spacing in between the orthogonal modes of the composite patch, to give circular polarization. Proposed configuration is investigated for angle increasing from 50 degrees to 100 degrees. An optimum response in terms of the bandwidth (BW) is obtained in 50 degrees modified isosceles patch. Here, input impedance and axial ratio (AR) BW of 646MHz (52%) and 76MHz (6.12%), respectively, is obtained. As an additional design feature, proposed configuration shows variation in the center frequency of AR BW against increasing isosceles angle and the offset distance. Proposed designs exhibit broadside radiation pattern with a gain of above 8dBi, with a good agreement between the simulated and measured results. A new simpler design for circular polarized response supported with detailed design methodology are the new technical contributions in the proposed work.