An interpolation-based approach for near field singularity treatment in the close vicinity of a Huygens's box source for electromagnetic simulations

Abstract

The equivalence principle allows for the replacement of a radiating structure with a Huygens's box resulting from a near-field scan obtained from either simulations or measurements. The near-field on the surface enclosing the structure is replaced by a set of equivalent electric and magnetic dipoles that can be used as sources for numerical simulations. In this manner., problems of high complexity can be handled, using less unknowns, by separately addressing the radiating structure and the surrounding diffracting objects. Furthermore, sometimes the antenna model is not available, and it must be considered as a black box. However, important challenges arise when the Huygens's box approaches a surrounding structure. Indeed, the near-field resulting from discretized equivalent dipoles presents a singularity at each dipole's position. Therefore, the obtained fields with the equivalent dipoles are not valid in the close vicinity of the Huygens's box. A novel method is proposed to handle the aforementioned singularity. It is based on the interpolation of the electromagnetic field between the non-singular region and the surface of the box. The field on the non-singular region is obtained using equivalence principle whereas the near field scan data is used to retrieve the field on the box surface.