A novel solenoidal basis for the MoM analysis of closed surfaces

In the electric field integral equation (EFIE) solved by the method of moments (MoM), it is well known that to avoid the ldquolow frequency breakdownrdquo the unknown current must be separated into a solenoidal part and a non-solenoidal remainder. In our previous works, we have posed more attention in generating an efficient Multi-Resolution (MR) basis for the non-solenoidal part of the current, keeping as solenoidal basis the standard loop basis. Instead here we propose a novel basis for the solenoidal part of the current, applying the MR concept also to this part. The developed basis is generated by a low complexity automatic algorithm, starting from a generic triangular mesh, without any constraints on mesh properties or topology. We have verified that in the case of closed structures, the conditioning of the solenoidal MoM sub-matrix (and consequently of the entire MoM matrix) is much lower than using the standard loop basis, where an arbitrary elementary (point) loop must be deleted.