Near field scan alignment procedure for electrically large apertures

Timothy Sleasman, Mohammadreza F. Imani, Okan Yurduseven, Kenneth P. Trofatter, Vinay R. Gowda, Daniel L. Marks, Jonah N. Gollub, David R. Smith

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Computational imaging at microwave frequencies has gained traction due to its potential for obtaining high-quality images with fast acquisition rates. Complex and diverse radiation patterns form the cornerstone of this approach. Electrically large antennas, such as modemixing cavities and metamaterial apertures, have proven to be effective platforms for generating such waveforms. Due to the complex nature of these antennas, near field scanning is often required to characterize their radiation patterns. However, accurate knowledge of the produced waveforms' spatial distribution, with respect to the physical position of the antenna, is imperative. This relies on precise alignment between the antenna and the near field scan stage during the characterization process-a requirement that is especially cumbersome to achieve when operating at high frequencies. We present an effective method to address this problem; by introducing RF markers into the antenna the position of the antenna under test within the near field scanning setup can be obtained directly from the measurements. The proposed method is experimentally verified through comparison with measurements made using optical photogrammetry. The proposed process will find application in the alignment of computational and multistatic imaging systems, commonly used in security screening and threat detection, as well as in tiled electrically large antenna structures.

Original languageEnglish (US)
Article number7893760
Pages (from-to)3257-3262
Number of pages6
JournalIEEE Transactions on Antennas and Propagation
Issue number6
StatePublished - 2017
Externally publishedYes


  • Antenna radiation patterns
  • Microwave antenna arrays
  • Microwave imaging
  • Multi-in multi-out systems
  • Near fields
  • Nonuniformly spaced arrays
  • Optical position measurement
  • Radar position measurement
  • Sparse array antennas

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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