McAuley, I. and Murphy, J.Anthony and McCarthy, Darragh and Gradziel, Marcin and Mahon, R. and O'Sullivan, Créidhe and Trappe, Neil (2016) Determination of the Phase Centers of Millimeter-Wave Horn Antennas Using a Holographic Interference Technique. Journal of Infrared, Millimeter and Terahertz Waves, 37 (4). pp. 340-355. ISSN 1866-6892

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Abstract

In this paper, we discuss how a holographic interference technique can be applied in the experimental determination of the phase centers of non-standard horn antennas in the millimeter-waveband. The phase center is the point inside the horn from which the radiation appears to emanate when viewed from the far-field, and knowing its location is necessary for optimizing coupling efficiencies to quasi-optical systems. For non-standard horn designs, and other feed structures, the phase center may be difficult to reliably predict by simulation, in which case, before committing to antenna manufacture, there is a requirement for it to be determined experimentally. Although the phase center can be recovered by direct phase measurement of the far-field beam pattern, this usually involves expensive instrumentation such as a vector network analyzer for millimeter wave horn antennas. In this paper, we describe one inexpensive alternative, which is based on measuring the interference pattern in intensity between the radiation from the horn of interest and a reference beam derived from the same coherent source in an off-axis holography setup. The accuracy of the approach is improved by comparison with the interference pattern of a well-understood standard horn (such as a corrugated conical horn) in the same experimental setup. We present an example of the technique applied to a profiled smooth-walled horn antenna, which has been especially designed for cosmic microwave background (CMB) polarization experiments.

Item Type:	Article
Additional Information:	The authors would like to acknowledge the financial support of the European Space Agency, Enterprise Ireland and the Irish Research Council for the work described in this paper.
Keywords:	Horn antenna; Phase center; Millimeter- and submillimeter-wave; Measurement; Holography;
Academic Unit:	Faculty of Science and Engineering > Experimental Physics
Item ID:	9795
Identification Number:	https://doi.org/10.1007/s10762-015-0235-8
Depositing User:	Dr. Marcin Lukasz Gradziel
Date Deposited:	17 Aug 2018 15:55
Journal or Publication Title:	Journal of Infrared, Millimeter and Terahertz Waves
Publisher:	Springer
Refereed:	Yes
Funders:	European Space Agency, Enterprise Ireland, Irish Research Council
URI:	https://link.springer.com
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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