A Single Polarization Absorptive-Diffusive Frequency- selective Radome Based on Hybrid Two-dimensional and Three-dimensional Structure

A novel frequency-selective rasorber (FSR) based on hybrid two-dimensional (2-D) and three-dimensional (3-D) structures is proposed, which provides a high-efficiency transmission band and a broadband radar cross section (RCS) reduction by hybridizing diffusion and absorption. By utilizing the periodicity of the lossy-dipole which transmits electromagnetic (EM) waves when the lossy-dipole operates in half-wavelength mode (2f(0)) and whole-wavelength mode (4f(0)). It can absorb EM wave at the frequency f(0) and 3f(0) by loading lumped resistor on 3-D folded dipole. A 2-D band-pass frequency selective surface operating at 2f(0) is designed, which acts as an equivalent ground for the other layers outside the transmission band. At the frequency of 4f(0), the EM wave transmits through the folded lossy-dipole. Therefore a polarization convert structure is used to broaden the stealth band at 4f(0). The results show that the transmission greater than 80% in the frequency range of 8.0 to 10.2 GHz with a 24.2% fractional bandwidth. In addition, from 1.95 to 5.16 GHz and 12.5 to 14 GHz the absorption is more than 80%. Finally, the polarization convert rate greater than 80% in the frequency range of 14 to 20GHz. The proposed structure has a broad application prospect in radar radome for its broadband stealth performance.