Upper bounds on scattering processes and metamaterial-inspired structures that reach them

Inigo Liberal, Inigo Ederra, Ramón Gonzalo, Richard W. Ziolkowski

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The physical limitations on time-harmonic scattering processes are investigated on the basis of the optical theorem. Previously derived least upper bounds on the total scattering and absorption cross sections are obtained from it in a straightforward manner. In addition, it reveals a practical upper bound for the bistatic cross-section when evaluated in any direction. It is proved further that the maximum upper bound of the bistatic cross section occurs in the forward-scattering direction and that the corresponding upper bound for the backscattering direction is four times smaller than this maximum value. Metamaterial-inspired electrically small antennas and scattering particles that approach these upper bounds are demonstrated. These examples numerically validate the derived upper bounds, as well as illustrate the important physical principles underlying them.

Original languageEnglish (US)
Article number6905732
Pages (from-to)6344-6353
Number of pages10
JournalIEEE Transactions on Antennas and Propagation
Issue number12
StatePublished - Dec 1 2014


  • Antenna theory
  • electrically small antennas
  • electromagnetic scattering
  • physical bounds

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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