TABLE OF CONTENTS Before discussing the various aspects of radar cross section prediction and control, it is helpful to introduce a few fundamental concepts. Many of these methods will be familiar from antenna studies, in which case this chapter serves as a review. However, the discussions and examples in this chapter will be directed toward RCS problems. The application of these methods to RCS can be substantially different from their corresponding antenna applications.
As in antenna theory, we consider fields to be set up by a combination of impressed electric and (in general) magnetic currents. Currents are induced such that the fields satisfy the boundary conditions and Maxwell s equations. The radiation integrals provide a means of calculating the fields due to a prescribed set of currents. Unfortunately, the currents on a body are usually not known. It is necessary to find the currents first or, at least, to provide an estimate of them. Finding the current involves solving a differential or integral equation; these methods will be discussed in Chapters 3 and 4. A good guess for the current is provided by the physical optics approximation presented in Sec. 2.10. First, several theorems are introduced that will be used to advantage in subsequent sections to formulate and solve scattering problems.
In general, the uniqueness theorem states that a solution to Maxwell s equations that satisfies the boundary conditions is unique. More specifically of interest to us is the following result: For a...
