Circularly polarized tilted beam microstrip antenna

A microstrip antenna couplet on a periodic patterned ground plane is proposed to provide circularly polarized tilted beam. Circular polarization is achieved by employing two wide microstrip antenna elements designed to operate in C-band. The elements are fed at the corners with 90⁰ phase difference along a travelling wave microstrip feed line. A novel concept of patterned slotted ground plane is utilized in tilting the main beam from the broadside. The slot patterns on the ground plane and the dimensions of microstrip patches and their angle with respect to the feed line are optimized to achieve wideband axial ratio. The designed antenna exhibits a maximum gain of 3.2dB with beam pointing angle at 30⁰ and operates over a bandwidth of around 8% for a VSWR <;2. Circular polarization beamwidth for axial ratio <;3dB is around 44⁰.