Editor's Notes

Feature Article

A Theory of Antenna Electromagnetic Near Field—Parts I and II
Said M. Mikki and Yahia M. Antar

Abstract: We present in this work a comprehensive theory of antenna near fields in two parts, highlighting in particular the engineering perspective. Part I starts by providing a general conceptual framework for the more detailed spectral theory to be developed in Part II. The present paper proceeds by proposing a general spatial description for the electromagnetic field in the antenna exterior region based on an asymptotic interpretation of the Wilcox expansion. This description is then extended by constructing the fields in the entire exterior domain by a direct computation starting from the far-field radiation pattern. This we achieve by deriving the Wilcox expansion from the multipole expansion, which allows us to analyze the energy exchange processes between various regions in the antenna surrounding domain, spelling out the effect and contribution of each mode in an analytical fashion. The results are used subsequently to evaluate the reactive energy of arbitrary antennas in a complete form written in terms of the TE and TM modes. Finally, the concept of reactive energy is reexamined in depth to illustrate the inherent ambiguity of the circuit total electric and magnetic reactive energies. We conclude that the reactive field concept is inadequate to the characterization of the antenna near field in general. Read more.

Announcements

Web Site Information and Updates

The inaugural launch of the AP-S web site leaves a few areas “under construction”. These include the For Students tab, the Ask an Expert feature and AP Fellows on the Cutting Edge. Updates to these sections of the web site will follow shortly.

In the For Student section of the site, we intend to add education resources, which will include the capability to download a number of IEEE AP-S training videos. With Ask an Expert, we intend to add a feature that will allow students to ask recognized experts in the field basic questions regarding antennas, electromagnetics and wave propagation. We have some implementation considerations to work out on this feature before it goes live. Finally, with AP Fellows on the Cutting Edge we intend to have short feature comments from recently elected AP-S Fellows on critical topics in antennas and electromagnetics.

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