Modified Rectangular Patch Radiator for Microstrip Active Antennas

The applicability of a modified rectangular microstrip patch radiator for active antenna with one-port active element has been demonstrated. The modified rectangular patch antenna, designed for the operating frequency of 3.4 GHz, was manufactured and tested. The inverter line was placed inside the rectangular opening in the central part of the patch. The active patch element for the 9.1 GHz frequency was realized. Co-polar and cross-polar radiation patterns, spectral purity and EIRP have been measured. Oscillating antenna using modified patch showed a higher spectral purity and substantially lower cross-polar levels in comparison with the active patch antenna realized with unmodified rectangular patch.