Use of Computational Electromagnetics to Enhance the Accuracy and Efficiency of Antenna Pattern Measurements

Heng Chen, Tapan Kumar Sarkar, Ming Da Zhu, Magdalena Salazar-Palma

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

The objective of this paper is to illustrate that computational electromagnetics can be used very effectively to improve the accuracy and efficiency of antenna pattern measurements. This is accomplished by moving a single probe over the measurement plane to generate enhanced accuracy in planar near field to far field transformation than over the classical Fourier based modal expansion methods. It is also illustrated that this method provides reliable results for cases when the conventional method fails for the case when the actual source plane and the measurement plane are equal in size. Also in this approach there is no need to incorporate probe correction unlike in the existing approaches. In addition a methodology can be designed where one can use an array of probes instead of moving a single probe over the measurement plane, thus improving the accuracy and efficiency of the measurements. In the use of the probe array there is also no need to perform probe correction. This proposed novel methodology is accomplished by solving for the equivalent magnetic current over a plane near the original source antenna and then employing the Method of Moments approach to solve for the equivalent currents on this fictitious surface. For this proposed methodology even though there is no need to satisfy the Nyquist sampling criteria in the measurement plane, a super resolution can be achieved in the solution of the equivalent magnetic current so that one can predict the status of the operation of each antenna elements in an array. Also the presence of evanescent fields in the measurements do not make this methodology unstable unlike in the conventional Fourier based techniques. The two components of the equivalent magnetic currents can be solved independently from the two measured components of the electric fields by solving the resultant Method of Moments matrix equation very efficiently and accurately by using the iterative conjugate gradient method enhanced through the incorporation of the Fast Fourier Transform (FFT) techniques. Sample numerical results are presented to illustrate the potential of a novel planar near field to far field transformation applied to the planar near field measurement technique.

Original languageEnglish (US)
JournalIEEE Journal on Multiscale and Multiphysics Computational Techniques
DOIs
StateAccepted/In press - Jan 1 2018

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Keywords

  • Antenna diagnostics
  • Conjugate Gradient Method
  • equivalent currents
  • FFT
  • integral equations
  • Measurements without probe correction
  • Planar near Field to far field Transformation
  • source reconstruction method (SRM)
  • super resolution reconstruction

ASJC Scopus subject areas

  • Computational Mathematics
  • Mathematical Physics
  • Modeling and Simulation
  • Physics and Astronomy (miscellaneous)

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