Positioning of orthogonally-polarized waveguide probes for near-field antenna measurement

Sabin Kumar Karki, Juha Ala-Laurinaho, Ville Viikari, Ari Alanne, Paul Moseley, Massimiliano Simeoni

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


In planar near-field antenna measurement, the full polarization characterization time of an antenna-under-test can be shortened by simultaneously using orthogonally-polarized probes. This paper discusses the positioning of two orthogonally-polarized probes in a near-field scanning system. The studies are conducted through full-wave simulations of tapered open-ended WR-75 waveguides operating at Ku-band. The studied probe characteristics are the mutual coupling between the orthogonallypolarized probes and the radiation pattern. The simulation studies concluded that the positioning along the major axes of the probe affects the radiation pattern more whereas the positioning along the diagonal direction increases the mutual coupling between orthogonal polarizations. Thus, the appropriate positioning is a tradeoff between these two parameters. For example, in order to maintain the ripples in the radiation pattern below 0.3 dB within +/- 60 degrees and port-to-port isolation below -35 dB, the orthogonally-polarized probes are recommended to be separated by more than 2-lambda distance and aligned along the diagonal direction.

Original languageEnglish
Title of host publication15th European Conference on Antennas and Propagation, EuCAP 2021
Number of pages5
ISBN (Electronic)9788831299022
Publication statusPublished - 22 Mar 2021
MoE publication typeA4 Article in a conference publication
EventEuropean Conference on Antennas and Propagation - Dusseldorf, Germany
Duration: 22 Mar 202126 Mar 2021
Conference number: 15


ConferenceEuropean Conference on Antennas and Propagation
Abbreviated titleEuCAP


  • antenna measurement
  • mutual coupling
  • near-field probe
  • near-field scanning
  • open-ended waveguide
  • probe compensation


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