A macro-element compression for the moment method

A new approach based on QR compression of the off-diagonal blocks of the impedance matrix arising in integral equations solutions of electromagnetic (EM) scattering problems, previously implemented for finite and irregular gratings, is extended here to an arbitrarily shaped obstacle. The main tool consists in dividing the entire surface scatterer into subdomains and in assembling the global impedance matrix as a combination of the macromatrices associated to each interaction of any patch on the other. The correlation between compression rate and accuracy of field computation is drawn up. An experimental study is performed to optimize the method relatively to the two competing parameters: accuracy and cost. Finally, it is shown that this method works equally well in both the high and the low frequency domain and also with an inclusion of a small detail in a large object