A Novel Low RCS Microstrip Antenna Using Aperture Coupled Microstrip Dipoles

Abstract

A microstrip antenna composed of parallel dipoles of different widths fed by rectangular slots cut in the ground plane of a microstrip line is designed for low RCS property. Based on the surface current distribution on the patch, the effects of cutting slots in the patch and the ground plane on the resonant modes which have a unique relationship with the radiation performance and RCS response of a microstrip antenna are discussed. By properly controlling resonant modes, the proposed antenna realizes good radiation performance and low RCS. Compared to the rectangular patch antenna with the same operating frequency, the proposed antenna, with only a 0.5 dB reduction of gain, has an RCS reduction of approximately 2–10 dB in the vicinity of the peaks illuminated by the plane wave from different incidence directions. Additionally, the antenna bandwidth does not decrease, which overcomes the problem that the RCS reduction techniques cause the loss of bandwidth.