Wideband RCS Reduction of Fabry-Perot Antenna Based on Diffuse Scattering Method

Three methods to reduce the RCS of Fabry-Perot(FP) resonator antenna using diffuse scattering are verified and compared in this paper. They are 1 bit random coding, 2 bit random coding and 2 bit random phase gradient coding method respectively. In order to realize reflection phase coding, a receiver-transmitter type unit with adjustable reflection phase from top side is proposed. Metasurface (MS) composed of this unit is the best choice to achieve the RCS reduction of FP resonator antenna, because it has the ability to independently control the reflection phase on both sides. By changing the size of the unit radiation patch, two units with 90° reflection phase difference or four units with 90° reflection phase difference from top side can be obtained. They can be used to compose MSs with different reflection phase distributions. These MSs can form FP resonator antennas with RCS reduction characteristics. Subsequently, simulated results of these three antennas are compared. The results show that the RCS reduction method of FP resonator antenna using 2-bit random phase gradient coding has the best performance. It achieves the wideband RCS reduction of antenna and has the least influence on antenna gain and radiation pattern. It enables FP resonator antenna to achieve an average RCS reduction of 12dB over the bandwidth range of 7.7–13.7GHz while maintain a peak gain of 18dB.