Gounot Y., Musafir R.

The present paper investigates properties of the solutions obtained with the equivalent sources method in scattering problems with the aim of identifying suitable source configurations. Simple geometry scatterers are considered — a cube and parallelepipeds with different aspect ratios — and four source supports are tested: linear, ‘double linear’ (made of two parallel lines), circular and elliptical. It was found that the supports providing best solutions differ according to the body geometry and the incidence angle of the impinging wave, suitable configurations being pointed out. Moreover, in the situations in which the other supports fail, the double linear one provides satisfactory solutions with a minimum number of sources. It is shown that indicators derived from the (complex) source strengths corresponding to the best solutions allow characterizing monopole sets that guarantee a good solution; admissible values for these indicators are proposed. Also, a rule that furnishes, for the cube, the optimal number of sources as a function of kL, is given for the circular and the simple linear supports. For the parallelepiped, a thumb rule for monopole positioning is proposed for the double linear support.