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.