Hybrid metasurface-based broadband high gain stealth antenna.

In this paper, a novel hybrid metasurface (HMS) is proposed for reducing antenna RCS and maintaining the gain of the antenna. The HMS consists of a polarization-selective absorbing surface (PSAS) and an asymmetric transmission metasurface (ATMS). PSAS can absorb the in-band and out-of-band x-polarized waves, while completely transmitting y-polarized waves. The out-of-band y-polarized waves transmitting the PSAS is reflected by the ATMS with 90° polarization rotation when the ATMS is located under the PSAS, and the reflected wave is absorbed by the PSAS. The in-band y-polarized wave passing through the PSAS can completely pass through the ATMS and the antenna array. Thus the RCS reduction of the antenna can be achieved. Based on antenna reciprocity principle, the in-band y-polarized wave radiated by the metasurface lens antenna can completely pass through the HMS. The measurement results show that the antenna RCS is significantly reduced for x-polarized and y-polarized incident waves in 8∼18 GHz. The 3 dB gain relative bandwidth of stealth antenna is 40% (8∼12 GHz). The realized gain of the antenna at the center frequency reaches 26.3 dB. It is noteworthy that the stealth antenna balances both radiation performance and scattering performance, which makes it have the merits of high gain and excellent stealth performance simultaneously.