AN ASYMPTOTIC ANALYSIS OF A WIRE MESH PARALLEL-PLATE WAVE-GUIDE

The method of steepest descents is applied to a parallel-plate wavegui de where one of the plates is a bonded wire mesh modeled by a sheet im pedance boundary condition. The structure is excited by a magnetic lin e source exterior to the waveguide. The parameters of the wire mesh ar e adjusted to exploit the contributions from the leaky-wave poles in t he near far-zone radiation pattern. The use of the asymptotic expressi ons in this region is justified by comparisons with results obtained b y numerical integration. The transient response of the structure is ob tained by transforming the frequency domain response to the time domai n with an FFT algorithm. An alternate representation for the magnetic field which is computationally efficient for determining the response in early time is derived. Numerical results for a double exponential p ulse excitation of the line source are presented.