Wideband RCS Reduction of a Linear Patch Antenna Array Using AMC Metasurface for Stealth Applications

This article presents a linear microstrip patch antenna array at the X-band that incorporates an aperiodic artificial magnetic conductor (AMC) metasurface which utilizes phase cancellation techniques for reducing both the in-band and out-of-band Radar Cross Section (RCS). The structure consists of two substrates with three layers, the top layer consists of 8 antenna elements along with AMCs which are aperiodically oriented for wideband RCS reduction, and the middle layer (in between the two substrates) consists of a corporate feed network for the antenna array, followed by the ground plane in the bottom layer. Few AMC blocks have been used to achieve a wideband RCS reduction in the frequency range of 6 GHz to 16 GHz with more than 85% reduction in both X- and Y-polarizations utilizing a low profile, compact design. Along with the monostatic RCS reduction, a bistatic RCS reduction up to 40(degrees) has also been observed in simulations. The proposed structure has been fabricated and measurements of the reflection coefficient, gain, patterns, and monostatic RCS plots have been carried out. Measured results indicate good agreement with the results of the simulations after considering all measurement errors.