Low-Cost Dielectric Reflective Surface for Low-Level Backscattered Diffuse Reflections

This article presents the design of non-subwavelength, non-resonant, and non-absorptive dielectric surface that creates a low-level backward diffuse reflections under illumination of a far-field plane wave at millimeter wave regime. Thus, radar cross section reduction of a solid metallic object can be achieved. The dielectric surface is consist of unit cells of only two different electric permittivity (epsilon (r1) = 6.14 and epsilon (r2) = 3.49) distributed across the surface aperture to achieve low-level backscattered diffuse reflections. The unit cells used are having non-subwavelength size (0.53 lambda(80GHz)) which ensures an easier fabrication of the presented surface using low cost simple PCB technology, in particular at high frequencies. RCS reduction of more than 10 dBsm is achieved from 70 to 87 GHz (BW ae 21.65 %) using the presented dielectric surface of optimized permittivity distribution. The RCS reduction capabilities of the presented surface are studied theoretically under both normal and oblique incidences and then fabricated and verified experimentally by reflectivity measurements.