Reformulation of the Roy–Shafai Generalization of the Ludwig-3 Co-/Cross-Polarization Definition
| Autor: | James S. McLean |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Antennas and Propagation. 69:3535-3537 |
| ISSN: | 1558-2221 0018-926X |
| DOI: | 10.1109/tap.2020.3030551 |
| Popis: | The Roy–Shafai generalization of the Ludwig-3 polarization pattern definition is well-suited to the representation of the far electromagnetic field of a flanged aperture, either a perfect electric conductor (PEC)-flanged aperture with an impressed electric field as was shown by Roy and Shafai or a perfect magnetic conductor (PMC)-flanged aperture with an impressed magnetic field which can be similarly derived. We show that the Roy–Shafai generalization of the Ludwig-3 polarization definition is in fact equivalent to the transformed Ludwig-2 definition. The Ludwig-3 polarization is that of a Huygens source, while the Ludwig-2 polarization definition corresponds to either an electric or, with transformation, a magnetic dipole. That the Roy-Shafai polarization definition is equivalent to a transformed Ludwig-2 definition is reasonable as the rectangular PEC-flanged aperture with an impressed electric field behaves as a magnetic dipole in the low frequency limit and, subject to some restrictions, maintains the same polarization pattern for all frequency assuming the aperture field remains uniform. Likewise, the rectangular PMC-flanged aperture with an impressed magnetic field behaves like an electric dipole in the low-frequency limit and maintains the same polarization pattern for all frequency again, assuming that the aperture field remains uniform and, thus, exhibits a Ludwig-2 polarization pattern. |
| Databáze: | OpenAIRE |
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