Diffraction of a short pulse by a slot in an impedance screen

Abstract

~In this paper, the diffraction of a short electromagnetic pulse by a slot in an impedance screen is studied using timespatial approach. The obtained integral equations of the problem were brought to the infinite system of Linear algebraic equations. The system of orthogonal functions for the expansion in the series of unknown integrands is undertaken the wavelet-basis, whose functions are well localized in time domains. AU matrix elements of the obtained system are represented in the form, convenient for the numerical integration. I. INTRODUCTION Theoretical analysis of scattering of short electromagnetic pulses is of interest for the application in the radar and the measurement technique. During the solution of boundary problems the methods, based on the solution of integral equations frequently applied [I]. The widespread approaches to the solution of the pulses diffiction problems on finite structures are based on the solution of these problems for the simple harmonic waves with the subsequent application of Fourier transform [Z, 31. This approach leads to the difficulties connected with the large volumes of calculations. In this connection solutions of Maxwell's equations in the time domain can be of interest. In this paper, the diffiction of a short electromagnetic pulse by a slot in an impedance screen is studied using time-spatial approach. The obtained integral equations are solved by the expansion of &own integrand in infinite-series in terms of wavelet basis fbctions [4, 51. 11. PROBLEM FORMULATION In the Cartesian coordinate system (x,y,z) thin impedance screen and slot by width 2a (-a < x < a) are located between two dielecbic half-spaces with permittivity El and E2 for upper and lower half-spaces accordingly. The plane of the screen complies with the coordinate plane z = 0. The screen is characterized by surface impedanceZZo, zo =a - is the he space wave impedance. The incident electromagnetic field is created by thin and infinite wire of magnetic current orionted along the axisy . Coordinates of source are ( xo , zo). The current densit): is j(x, z,r) = Jm(t)G(x - xo)S(z - zo) . The dependence of current on the time is the Gaussian pulse, and J (t) = J, exp(-t' I r2). The problem is two-dimensional, a 1% = 0 .