Bandwidth Limits and Other Considerations for Monostatic RCS Reduction by Virtual Shaping

摘要

This work addresses some major issues in the adaptation and application of microstrip patch antenna and reflectarray technology to radar cross section reduction by virtual shaping. We define virtual shaping to be any technique used to cause the shape and orientation of an object as it affects a scattered radar signal to differ from the actual physical shape and orientation of the object. This is accomplished by introducing a linear phase gradient on the incident wave as it is scattered from various parts of the target surface. By this method a vertical surface can be made to appear to radar to be skewed from the vertical as is done in conventional shaping for radar cross section reduction. Virtual shaping has the potential to reduce the negative impacts imposed by conventional shaping on other ship design considerations such as hydrodynamics, stability, payload, and arrangements while maintaining or enhancing the signature control aspects. Microstrip patch antenna and reflectarray technologies offer a theoretical and practical basis for development of virtual shaping techniques; however, the goals of antenna design and the radiation characteristics of reflectarrays when applied to conventional uses of these technologies differ from those considerations when applied to signature control and radar cross section reduction. The major issues of these technologies that become more critical when applied to virtual shaping include (1) limited bandwidth, (2) high sidelobes, and (3) reflections from exposed dielectric surfaces. This paper summarizes efforts that have the potential to extend these technologies to virtual shaping.