INVESTIGATION OF POLARIZATION PURITY AND PORT ISOLATION IN LINEARLY AND CIRCULARLY POLARIZED MICROSTRIP PATCH ANTENNAS WITH GROUND PLANE SERRATIONS

摘要

This paper investigates the application of serrations to the ground plane of a diagonal fed and dual fed microstrip patch antenna. Polarization characteristics as well as port isolation for the dual fed case are examined. Previous studies on polarization purity enhancements with serrated ground planes have shown as much as a 10dB reduction in cross polarization radiation for a probe fed linearly polarized microstrip antennas on finite ground planes. Along with greater polarization purity, moderate increases in the 3dB beamwidth and tunability also arise from the use of serrations along the ground plane in the single fed linearly polarized case. With this in mind, serrations are applied to similar patch geometries with different feeding schemes to attain dual orthogonal linear polarization as well as circular polarization. Measurements of both cases highlight effects of serrations on radiation parameters, impedance, and port isolation in the dual fed case.