Ultra-wideband direction-of-arrival considerations for antenna arrays in the presence of mutual coupling

David B. Alexander, Ram M. Narayanan, Braham Himed

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


This paper discusses the theoretical considerations for direction-of-arrival (DOA) estimation using antenna arrays in the presence of mutual coupling. In arrays, the relative proximity of antenna elements results in some manner of near-field mutual coupling that can negatively impact the array performance. In particular, mutual coupling can degrade the quality of DOA estimations and reduce the ability of the array to perform high-quality correlation processing and direction finding. The expected variance of an array performing DOA estimation is inversely related to the Fisher information matrix of the system. Theoretical radiated fields of a linear antenna array were compared to more realistic behavior of the equivalent architectures produced in electromagnetics simulation software. The mutual coupling between all the elements in an array can be a difficult phenomenon to precisely define, as it is an iterative process with many higher-order effects. To circumvent this, a mutual coupling matrix is defined as the relation between the theoretical radiation characteristic of an array and its simulated counterpart. An inverse solution method was used to solve for the mutual coupling interactions. The expected impact of mutual coupling in a DOA estimation context was then mathematically established by propagating the mutual coupling matrix through calculation of the Fisher information matrix and compared to the case of no mutual coupling. It was found that taking mutual coupling into consideration yields a higher Cramer-Rao Lower Bound and as a result a greater RMS angle error in a DOA estimation context. Mutual coupling was also found to have a somewhat greater impact on the Cramer-Rao Bound at S-band than at X-band.

Original languageEnglish (US)
Title of host publicationRadar Sensor Technology XXII
EditorsArmin Doerry, Kenneth I. Ranney
ISBN (Electronic)9781510617773
StatePublished - 2018
EventRadar Sensor Technology XXII 2018 - Orlando, United States
Duration: Apr 16 2018Apr 18 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherRadar Sensor Technology XXII 2018
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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