Cross polarization in swept beam THz imaging systems using off-axis parabolic mirrors

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Journal Title
Journal ISSN
Volume Title
Conference article in proceedings
Date
2022
Major/Subject
Mcode
Degree programme
Language
en
Pages
4
Series
2022 16th European Conference on Antennas and Propagation, EuCAP 2022, Proceedings of the European Conference on Antennas and Propagation
Abstract
The optical behavior of a terahertz imaging system employing a train of four identical off-axis parabolic mirrors with oblique incidence angle illumination is investigated in this work. The aperture filling and aberrations of a single off-axis parabolic mirror when illuminated by a Gaussian terahertz beam at its focus point is measured and simulated. The amplitude of E-field in transverse electric (TE) and transverse magnetic (TM) polarizations at target plane reveals a significant cross polarization, even when there is zero cross polarization at the source beam, amplitude of which is ∼ 33% of TE polarization. The investigation of the E-field on the detector plane reveals that this ratio is ∼ 1.5% at the detector plane, and the cross polarized E-field at the target plane is rotated back to co polarization. Although its amplitude is negligible, the TM distribution at detector plane is bimodal and tilted about the optical axis.
Description
Publisher Copyright: © 2022 European Association for Antennas and Propagation.
Keywords
off-axis parabolic mirror, polarization, sub-millimeter wave, THz
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Citation
Rezapoor , P , Tamminen , A , Nefedova , I , Ala-Laurinaho , J , Llombart , N , Rodilla , H , Stake , J & Taylor , Z 2022 , Cross polarization in swept beam THz imaging systems using off-axis parabolic mirrors . in 2022 16th European Conference on Antennas and Propagation, EuCAP 2022 . Proceedings of the European Conference on Antennas and Propagation , IEEE , European Conference on Antennas and Propagation , Madrid , Spain , 27/03/2022 . https://doi.org/10.23919/EuCAP53622.2022.9769500