Diffraction from tapered resistive junctions

Resistive sheets are often used for radar-cross section reduction by providing a transition from a metal edge to free space. In this work, the authors present an exact TM (transverse magnetic) diffraction coefficient for a joint formed by two abutting tapered resistive sheets whose resistivity is zero at the junction but increases linearly away from it. The procedure used for the derivation of the diffraction coefficient is similar to that employed by S.-I. Yang et al. (1988). This leads to a result which is only applicable to linearly tapered sheets and TM incidence. Thus, for TE (transverse electric) incidence and junctions formed by quadratically tapered half planes, the authors resort to an approximate solution based on physical optics (PO) approximation. The derived rigorous analytical and PO diffraction coefficients are compared with numerical data generated from an appropriately chosen finite structure which simulates the junction in the infinite plane. On the basis of the generated numerical data, the authors validate the rigorous TM diffraction coefficient and determine the accuracy of the PO diffraction coefficients.<>