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Electric dipole power emission near an ENZ medium

2019; Taylor & Francis; Volume: 66; Issue: 20 Linguagem: Inglês

10.1080/09500340.2019.1690712

1362-3044

Zhangjin Xu, Henk F. Arnoldus,

Microwave and Dielectric Measurement Techniques

Power emission by an electric dipole near an interface is considered. We derive explicit expressions for the emitted power for any state of oscillation of the dipole, without making use of the material properties of the substrate, and we derive an expression for the power crossing the interface. It is shown that the power naturally splits in contributions from travelling and evanescent incident waves. Only the part with the evanescent waves contributes to the transmitted power. We then consider an epsilon-equal-zero material and obtain explicit expressions for the power. It is shown that only travelling waves contribute, and that no power crosses into the material. When the slightest amount of absorption is present in the medium, the evanescent waves kick in, and in such a way that the emitted power diverges when the distance between the dipole and the interface becomes small.