Stored energies in electric and magnetic current densities for small antennas
(2015) In Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences 471(2176). p.123 Abstract
 Electric and magnetic currents are essential to describe electromagneticstored energy, and the associated antenna Q and the partial directivity to antenna Qratio, D/Q, for arbitrarily shaped structures. The upper bound of previous D/Q results for antennas modelled by electric currents is accurate enough to be predictive. This motivates us to develop the analysis required to determine upper and/or lower bounds for electromagnetic problems that include magnetic model currents. Here we derive new expressions for the stored energies, which are used to determine antenna Q bounds and D/Q bounds for the combination of electric and magnetic currents, in the limit of electrically small antennas. In this investigation, we show both new analytical... (More)
 Electric and magnetic currents are essential to describe electromagneticstored energy, and the associated antenna Q and the partial directivity to antenna Qratio, D/Q, for arbitrarily shaped structures. The upper bound of previous D/Q results for antennas modelled by electric currents is accurate enough to be predictive. This motivates us to develop the analysis required to determine upper and/or lower bounds for electromagnetic problems that include magnetic model currents. Here we derive new expressions for the stored energies, which are used to determine antenna Q bounds and D/Q bounds for the combination of electric and magnetic currents, in the limit of electrically small antennas. In this investigation, we show both new analytical results and we illustrate numerical realizations of them. We show that the lower bound of antenna Q is inversely proportional to the largest eigenvalue of certain combinations of the electric and magnetic polarizability tensors. These results are an extension of the electric only currents, which come as a special case. The proposed method to determine the minimum Qvalue which is based on the new expressions for the stored energies, also yields a family of currentdensity minimizers for optimal electric and magnetic currents that can lend insight into antenna designs. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/5205005
 author
 Jonsson, Lars and Gustafsson, Mats ^{LU}
 organization
 publishing date
 2015
 type
 Contribution to journal
 publication status
 published
 subject
 keywords
 stored energy, antennas, polarizability tensors, Qfactor, physical bounds
 in
 Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences
 volume
 471
 issue
 2176
 pages
 1  23
 publisher
 Royal Society
 external identifiers

 Scopus:84926303291
 ISSN
 13645021
 DOI
 10.1098/rspa.2014.0897
 project
 EIT_CACOEMD Complex analysis and convex optimization for EM design
 language
 English
 LU publication?
 yes
 id
 f0be0a5e07da478a806053d306f86b83 (old id 5205005)
 date added to LUP
 20150330 12:59:33
 date last changed
 20161013 04:30:06
@misc{f0be0a5e07da478a806053d306f86b83, abstract = {Electric and magnetic currents are essential to describe electromagneticstored energy, and the associated antenna Q and the partial directivity to antenna Qratio, D/Q, for arbitrarily shaped structures. The upper bound of previous D/Q results for antennas modelled by electric currents is accurate enough to be predictive. This motivates us to develop the analysis required to determine upper and/or lower bounds for electromagnetic problems that include magnetic model currents. Here we derive new expressions for the stored energies, which are used to determine antenna Q bounds and D/Q bounds for the combination of electric and magnetic currents, in the limit of electrically small antennas. In this investigation, we show both new analytical results and we illustrate numerical realizations of them. We show that the lower bound of antenna Q is inversely proportional to the largest eigenvalue of certain combinations of the electric and magnetic polarizability tensors. These results are an extension of the electric only currents, which come as a special case. The proposed method to determine the minimum Qvalue which is based on the new expressions for the stored energies, also yields a family of currentdensity minimizers for optimal electric and magnetic currents that can lend insight into antenna designs.}, author = {Jonsson, Lars and Gustafsson, Mats}, issn = {13645021}, keyword = {stored energy,antennas,polarizability tensors,Qfactor,physical bounds}, language = {eng}, number = {2176}, pages = {123}, publisher = {ARRAY(0xa69c5b0)}, series = {Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences}, title = {Stored energies in electric and magnetic current densities for small antennas}, url = {http://dx.doi.org/10.1098/rspa.2014.0897}, volume = {471}, year = {2015}, }