Ultra-wideband Low RCS Conformal Patch Array Antenna with a Modified Ground Plane

In this paper, a conformal patch array antenna with ultra-wideband low radar cross section (RCS) for cylindrical platform applications is designed, which can ensure the radiation performance and achieve prominent electromagnetic (EM) stealth. Firstly, a conventional planar 1×4 microstrip array antenna is designed as a reference antenna, and part of the ground of the antenna is modified to a metasurface structure composed of unit cells with various sizes, which are selected based on optimized multielement phase cancellation (OMEPC), so as to achieve ultra-wideband RCS reduction. Then, the structure is conformed on a cylinder to form a conformal array antenna, which can realize RCS reduction both in and out of the working frequency band of the array antenna. Meanwhile, the radiation performance is well maintained. The conformal array antenna can achieve a monostatic RCS reduction greater than 5 dB from 1 to 20 GHz, with an average reduction of 7.7 dB.