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Theoretical Consideration of Axial Ratio Deterioration in CP Loop-Shaped Antennas

Hisamatsu Nakano Orcid Logo, Tomoki Abe Orcid Logo, Amit Mehta Orcid Logo, Junji Yamauchi Orcid Logo

IEEE Antennas and Wireless Propagation Letters, Volume: 22, Issue: 5, Pages: 1035 - 1039

Swansea University Author: Amit Mehta Orcid Logo

Abstract

Conventionally, the deterioration in the axial ratio (AR) for a circularly polarized antenna based on a traveling wave current is explained using backward currents reflected from the antenna arm end. This letter reveals the existence of a new cause for AR deterioration in a situation of no backward...

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Published in: IEEE Antennas and Wireless Propagation Letters
ISSN: 1536-1225 1548-5757
Published: Institute of Electrical and Electronics Engineers (IEEE) 2023
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa62451
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Abstract: Conventionally, the deterioration in the axial ratio (AR) for a circularly polarized antenna based on a traveling wave current is explained using backward currents reflected from the antenna arm end. This letter reveals the existence of a new cause for AR deterioration in a situation of no backward currents. For this, a theoretical loop antenna model of one-guided wavelength circumference is constructed, where only a forward traveling wave current (a positive s '-directed current) flows with attenuation due to the radiation. The derived AR equation finds that the AR deteriorates due to the attenuation of the current, even when backward currents do not exist. Subsequently, a current that flows in the direction normal to the positive s '-directed current (a t '-directed current specified by perturbation weight p ) is added to the loop. It is found that the AR in the presence of the attenuating current is improved by virtue of the positive t '-directed current.
Keywords: Attenuation constant, axial ratio, circularly polarized radiation, forward current, perturbation length, traveling wave current
College: Faculty of Science and Engineering
Issue: 5
Start Page: 1035
End Page: 1039