Near-Field Antenna Measurements using a Lithium Niobate Photonic Probe
Authors: Vince Rodriguez, Brett Walkenhorst, and Jim Toney
Publication: EuCAP 2018
Copyright Owners: NSI-MI Technologies, Srico
Recently, a paper was presented in which a lithium niobate (LiNbO3) crystal electric field sensor was characterized as a possible probe for near-field antenna measurements. In the present paper, some preliminary measurements are presented. A standard gain horn operating in the X-band was measured in a spherical near-field range using the LiNbO3 probe as the near-field probe. The results are compared to computed data for said horn. An additional flat– plate, slotted array antenna operating in the X-band was also measured. The data was transformed to the far field and compared with previous measurements of said antenna performed using a traditional open-ended-waveguide (OEWG) probe. Additionally, the transform was used to backproject to the aperture of the antenna and the data show the two slots in the array that are covered with metallic tape. The transforms and back-projection suggest that these probes could be used as near-field probes in antenna measurements if some stability issues are corrected.