Solving time-harmonic EM problems using boundary conditions for normal field components

According to the uniqueness theorem for time-harmonic electromagnetic (EM) field, the field inside a finite domain v is uniquely determined by tangential electric (E_t) or magnetic (H_t) field on the bounding surface S, except on resonant frequencies of the domain. This leads to solution methods that enforces either E_t, or H_t, or both tangential components on S, e.g., in electric-, magnetic-, or combined-field integral equations (EFIE, MFIE, CFIE) methods. Some methods, e.g., augmented magnetic-field integral equation (AMFIE) method, employ normal component of the field too, but only in addition to tangential component, to avoid spurious resonant solutions. This paper shows that time-harmonic EM problems can be solved by enforcing boundary conditions for normal field components ( E_n and H_n) only.