Optimum design of N sheet capacitive Jaumann absorber using genetic algorithm

An optimun design for N(arbitrary)-sheet capacitive Jaumann elctromagnetic (EM) wave absorber; using genetic algorithm will be presented. This algorit hm is a random optimization method based on the genetic relation in the hum an being. We show the bandwidth for two-sheet capacitive Jaumann absorber c an be expanded even more than 108% showed by knott [1], by using this algor ithm and without imposing the double-notch design criteria. We also show th at our results approaches knott's results when we restrict the characterist ic impedances and lengths of the lines to vary within a very short range. W e also design one-sheet and three-sheet capacitive Jaumann absorbers. The o nly restriction used here is about the meaningful range for the design vari ables. The goal of this algorithm is that we can impose arbitrary restricti on about the range of the variation of the variables. So we can see the per formance behaviour with the range dimension of the variables, and we can ob tain different optimum results for different ranges. Finally we obtain a 20 -dB attenuation bandwidth more than 145% for one-sheet, 173% for two-sheet (compare with 108% obtained in [1]) and 193% for three-sheet capacitive Jau mann EM absorbers, with some acceptable short range for the variables. We d esign the one-sheet and two-sheet capacitive Jaumann absorbers at low frequ ency and the three-sheet at high frequency. the 20-dB attenuation bandwidth obtained for the one-sheet and two-sheet capacitive Jaumann absorbers are respectively, from 10 to 77 MHz and, from 4 to 61 MHz. For the three-sheet capacitive Jaumann absorber the 20-dB attenuation bandwidth obtained is, fr om 0.8 GHz to 280 GHz.