Abstract:
The radar echo characteristics of inanimate objects are given by the radar cross section
(RCS) of the object. The RCS is proportional to the ratio of the scattered power density
at the receiver to the incident power density at the target. Echo reduction and its effects
are often the important concern of modern radar designers. There are different types
employed to reduce the RCS, Shaping, radar absorbing material (RAM), passive
cancellation, active cancellation, and plasma field[1]. Cancellation methods require
loading the object with discrete antenna like elements (slots, dipoles or patches) whose
impedance must be chosen so as to cancel the returns from other parts of the body. In
this paper a cancellation technique is used to reduce RCS of a metallic object by using
array of microstrip patches designed at required frequency and distributed on the surface
of plate with different structures. The best structure of array of patches, which gives
minimum RCS independent of the polarization, is selected. The effects of height of
substrate, dielectric constant of substrate, the spaces between patches, and structure size
on RCS reduction are discussed. Computer simulations with ZELAND package and
measurements were performed to confirm the obtained results.