A circular polarization alterable square MPA with wide frequency tuning

Abstract

A wide-range frequency tunable (2.01 GHz–2.41 GHz) square patch antenna with simultaneous CP alteration ability is designed and its performance is analyzed. Frequency tuning is achieved by varying the capacitance of four varactors connected between the central portion and four additional segments of the main patch. Circular polarization at different bands are achieved by using a wideband 90° phase shifter and a DPDT switch is used to vary the sense of circular polarization rotation. The antenna shows very good axial ratio value at all frequencies with a maximum gain of 2.2 dBc.