Design and Application of the Switchable Electric/Magnetic Conductor Antenna

In this article, the concept of a radiable metal plane has been proposed for the first time, in which an antenna is attached tightly to the switchable electric/magnetic conductor (SEMC) surface. By isolating the radiation and scattering states using a p-i-n diode, a low-profile high-gain antenna and a reflector with the perfect electric conductor (PEC)-like reflection characteristics can be implemented in one structure. As a practical model, the SEMC based on the classical mushroomlike artificial magnetic conductor (AMC) is built and used to back a
$2\times $
2 array of the printed dipole, where the p-i-n diodes are mounted between each adjacent patch to switch PEC and AMC state. As a typical application, this unique radiable metal plane performed as a subarray is orthogonally arranged with a 90° sequential rotation feed network and integrates into a polarization conversion metasurface (PCM) in chessboard configuration to achieve the high-gain circularly polarized (CP) radiation and wideband 10-dB radar cross-section reduction (RCSR). A prototype is then fabricated and measured, and the experimental results show when p-i-ns are turned off, the sample is working as a CP antenna array, whose maximum realized gain of 14.3 dBi is obtained at 4.85 GHz with 31% aperture efficiency. When p-i-ns are turned on, the scattering of the sample is in stealth mode with 10-dB RCSR bandwidth ranging from 3.7 to 8 GHz with 73.5% fractional bandwidth including the operating band of the antenna.