Advanced Qualification · A-007 Feedlines and matching · A-007-005-003
Laquelle de ces antennes ne produit pas une polarisation circulaire?
- AAntenne hélice radiale ("loaded helicalwound")
- BDipôles en croix alimentés avec déphasage de 90 degrés
- CAntenne Lindenblad
- DAntenne hélice axiale ("axial-mode helical")
Correct answer: A — Antenne hélice radiale ("loaded helicalwound"). Question tirée de la banque officielle d'ISDE.
Why
A loaded helical-wound antenna typically radiates linear polarization because the loading coils are added to electrical lengthen the wire without changing its fundamental straight-wire shape or creating the necessary phase shift for circular waves. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching is section A-007 of the Advanced exam: Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.
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