An Inverse Equivalent Surface Current Solver with Zero-Field Enforcement by Left-Hand Side Calderón Projection

The inverse source problem of near-field antenna measurements is often formulated in terms of unknown equivalent electric and magnetic surface current densities. Exploiting just the constraints for the radiated field exterior to a closed Huygens surface results in ambiguous equivalent sources due to the excitation of non-radiating currents during the solution process. Therefore, enforcing the zero-field or Love side condition for the suppression of non-radiating currents based on a left-hand side preconditioner in the form of a Calderón projector is proposed. Transformation results based on realistic measurements demonstrate the effectiveness of this approach.