Optimum design of N sheet capactive Jaumann absorber using genetic algorithm

An optimum design for N(arbitrary)-sheet capacitive Jaumann electromagnetic (EM) wave absorber, using the genetic algorithm is presented. This algorithm is a random optimization method. We show the bandwidth for two-sheet capacity Jaumann absorber can be expanded even more than 108% as showed by Knott (see IEEE Trans.AP, vol.43, no.11, 1995), by using this algorithm and without imposing the double-notch design criteria. We also show that our results approaches Knott's results when we restrict the characteristic impedances and lengths of the lines to vary within a very short range. We also design one-sheet and three-sheet capacitive Jaumann absorbers. Finally we obtain a 20-dB attenuation bandwidth of more than 145% for one-sheet, 173% for two-sheet and 193% for three-sheet capacitive Jaumann EM absorbers, with some acceptable short range for the variables. We design the one-sheet and two-sheet capacitive Jaumann absorbers at low frequency 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 from 0.8 GHz to 280 GHz.