Diffraction by a finite parallel-plate waveguide cavity with perfect electric conductor loading: The case of E polarisation

Abstract

The diffraction by a finite parallel-plate waveguide cavity with perfect electric conductor loading is rigorously analysed for the E-polarised case using the Wiener–Hopf technique. By taking the Fourier transform to the unknown scattered field and applying boundary conditions in the transformed domain, the problem is formulated in terms of the simultaneous Wiener–Hopf equations. These equations are solved using the factorisation and decomposition procedure. The solution is exact but formal because it involves branch-cut integrals with unknown integrands and an infinite number of unknowns. Approximation procedures based on rigorous asymptotic are also presented, leading to an approximate solution of the Wiener–Hopf equations. The scattered field inside and outside the cavity is evaluated by taking the inverse Fourier transform and using the saddle point method of integration. Numerical computations of the radar cross-section have been performed for different physical parameters, providing a detailed analysis of the scattering characteristics.