# Using the optimization algorithm of Problem 9.2, find a stealth or low observable scatterer shape…

Using the optimization algorithm of Problem 9.2, find a stealth or low observable scatterer shape with as low as possible backscattering width over a 20? range of angles from 170? to 190? at f = 300 MHz. The scatterer must be such that a circular cylinder of radius 0.5? can fit inside it without touching the scatterer surface, and its longest dimension must be less than 10 ?. Model the scatterer as a PEC or a conductor with high conductivity. Earlier codes have computed bistatic scattering widths. For this problem, since we are interested in the backscattering direction the MoM postprocessing

»Using the optimization algorithm of Problem 9.2, find a stealth or low observable scatterer shape with as low as possible backscattering width over a 20? range of angles from 170? to 190? at f = 300 MHz. The scatterer must be such that a circular cylinder of radius 0.5? can fit inside it without touching the scatterer surface, and its longest dimension must be less than 10 ?. Model the scatterer as a PEC or a conductor with high conductivity. Earlier codes have computed bistatic scattering widths. For this problem, since we are interested in the backscattering direction the MoM postprocessing must be changed to compute monostatic scattering widths (fs = fi ). Use a mesh density of at least n? = 10 (although a courser mesh can be used in initial testing of the algorithm to save time). For your scatterer, prepare the following: (a) a plot of the scatterer shape; (b) the polyarc description; (c) a plot of the backscattering width from 0? to 360? (it is helpful to mark the 20? range with vertical lines); and (d) a plot of the convergence history of the optimization algorithm for your design (cost function value as a function of NelderMead iteration number). (e) Give the maximum value of the backscattering width over the range 170? = f = 190?.

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