Development of an Experimental Model of Low Frequency Dipole Radiation in the Presence of Multilayered Structures

The behaviour of electromagnetic fields in the presence of layered media has been studied and explored a lot, and utilized in numerous applications involving radio wave propagation. However, the works were done on simplified geometrical models, with ideal point dipole approximations, and therefore, were not practically very feasible. In this paper, we have developed a finite element method (FEM) simulation model which can be used to analyze practical dipole radiation characteristics in the low frequency (LF) near-field zone. The simulation environment is developed, and tested for various three-layered systems and compared with the results obtained using existing analytical methods. Both the analytical and the FEM simulation results indicate that the near-field response has strong dependence on the medium dielectric properties and thickness. The electric field vs. radial distance profiles have minima whose corresponding radial distances increase with increasing thickness of the dielectric, but decrease with the increase of the dielectric constant. These results appear to contain significant information on the medium dimensions and dielectric characteristics, signifying LF measurements to be a promising method for non-destructive measurements. Also, a slightly more complex structure with spherical air pores is examined and the field values, which could not be computed analytically, are determined through simulation. This overcomes the primary limitation of the analytical methods where one must always assume uniform layered structures for such calculations, and therefore the exploration domain is generalized.