Two-dimensional, highly directive currents on large circular loops

Margetis, D; Fikioris, G

dc.contributor.author	Margetis, D	en
dc.contributor.author	Fikioris, G	en
dc.date.accessioned	2014-03-01T01:50:33Z
dc.date.available	2014-03-01T01:50:33Z
dc.date.issued	2000	en
dc.identifier.issn	0022-2488	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/26048
dc.subject.classification	Physics, Mathematical	en
dc.title	Two-dimensional, highly directive currents on large circular loops	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	Properties of idealized, two-dimensional current distributions on circular loops are investigated analytically via the solution of a constrained optimization problem. The directivity in the far field is maximized under a fixed C = N/T, where N is the integral of the square of the current magnitude and T is the total radiated power. C enters the ensuing Fourier series for the current implicitly through a Lagrange multiplier alpha. For non-negative alpha and large electrical radius ka, the directivity and the current are evaluated approximately via combined use of the Poisson summation formula and the Mellin transform technique. As a result, a geometrical-ray representation for the current is derived for the case of directivities that are slightly larger than that of the uniform distribution. The analysis indicates certain advantages of large radiating structures for moderate values of the constraint C. In the limit C --> infinity of Oseen's "Einstein needle radiation," an asymptotic formula for the directivity is obtained. Possible extensions of these results to classes of smooth convex loops are briefly discussed. (C) 2000 American Institute of Physics. [S0022-2488(00)04109-8].	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	JOURNAL OF MATHEMATICAL PHYSICS	en
dc.identifier.isi	ISI:000088944400019	en
dc.identifier.volume	41	en
dc.identifier.issue	9	en
dc.identifier.spage	6130	en
dc.identifier.epage	6172	en