Full Wave Potential Formulation With Low-Frequency Stability Including Ohmic Losses

A time-harmonic full wave electromagnetic potential formulation is developed with stable broadband behavior including the static limit. The formulation ensures low-frequency stability not only when sub-domains with wavenumber proportional losses are present but also when sub-domains with ohmic losses are part of the computational domain. The low-frequency stability is achieved by introducing the induced electric charge distributions as unknowns in the sub-domains, where ohmic losses are present. To increase the numerical efficiency we utilize the so-called nodal charges that incorporate both volume and surface charge distributions into one scalar. Relevant numerical examples are presented to illustrate the zero-frequency stability of the formulation.