A Dielectric Panel Design for RCS Reduction and EM Shielding

A novel dielectric panel structure that contains no metal layer or conductive compound is proposed for electromagnetic shielding and radar cross section (RCS) reduction uses. It is configured as a planar slab with periodically positioned holes. By choosing appropriate slab thickness, material properties, aperture-to-dielectric area ratio, and hole spacing, the holey panel can suppress reflection and transmission at the same time for plane wave incidences. It conceals back scattering features of targets behind and the panel-to-target distance is not necessarily a fixed number. A thorough analysis is provided to explain how this metalless, nonabsorptive, periodic structure reduces the reflection level by deforming the plane wave with the propagation delay difference between air and dielectric regions. Simulated and measured results of a prototype designed in the E-band indicate that it can provide more than 15 dB RCS reduction at the designated transmission suppressing frequency and the 10 dB reduction bandwidth is more than 20%.