An Integrated Antenna Array With Broadband, Low-RCS, and High-Gain Characteristics

This communication presents an integrated structure of broadband low radar cross section (RCS) high-gain antenna array based on the frequency selective absorber (FSA), with significant electromagnetic reduction and antenna radiation functions. The FSA in the integrated structure consists of two layers, with the upper layer resistor and the lower layer grounded metal patch separated by an air layer. The bottom metal patch can also serve as an antenna radiator, and the structure area does not cause an additional increase in scattering RCS. By adjusting the shape and size of the bottom patch, a chessboard configuration low-RCS antenna array can be designed to achieve radiation and diffuse scattering functions. Broadband low-RCS antenna arrays exhibit excellent radiation performances by loading the feeding network, and in the stealthy receiving state, combined with the absorber function, antenna arrays can achieve both in-band and out-of-band broadband RCS reduction (RCSR). A $4\times 4$ integrated structure is processed and tested, and the functionality of the designed broadband low-RCS antenna array is verified. Simulation and experimental results show that the broadband low-RCS antenna array achieves a realized gain of 14.9 dBi at 5.3 GHz and obtains a monostatic RCSR greater than 10 dB for x and y polarization under normal incidence in the range of 3.15–8.75 GHz.