Shadowing a Small Size but Large Radar Cross Section Object with a Large Size but Small Radar Cross Section Object

Radar cross section (RCS) is not necessarily in direct proportion to object size, particular structure shape that can cause multiple reflection usually has larger RCS. In this article we demonstrate how a small object with a large RCS, like the corner reflector, can be shadowed by a large object with a small bistatic RCS for certain direction, like a fighter engine air inlet, to achieve RF stealth effect in certain direction. Multi-level-fast-multipole-method (MLFMM) simulations are used to calculate the RCS of these two structures in S-band, and compare their RCS when the corner reflector is placed inside the air inlet. Results show RCS reduction up to 17 dBs is possible, but the combined RCS is not as small as the air inlet itself because reflection from the corner reflector can still find its way out to the radar.