Resonant effects and near-field enhancement in perturbed arrays of metal dipoles

The equivalent self impedance of a perturbed array of metal dipoles is derived and the resonant effects upon plane wave illumination are studied. It is revealed that as a result of the perturbation, the scattering within a frequency range is dominated by the excitation of the odd mode. This corresponds to significant deviation compared to the unperturbed case. It is demonstrated that within this frequency range, very strong near- fields are excited in the vicinity of the array. Following a careful calculation of the near-fields using the periodic method of moments, the near-fields for a number of perturbed array designs are calculated and an increase in the near-field strength of more than 70 times compared with the incidence is demonstrated. The results are corroborated with HFSS.