Advanced Qualification · A-007 Feedlines and matching · A-007-005-002
Quel type de polarisation deux dipôles disposés en forme de croix produiront-ils si leurs alimentations sont déphasées de 90 degrés?
- AAucune de ces réponses, les deux champs s'annulent
- BUne polarisation circulaire
- CUne transpolarisation ("crosspolarization")
- DUne polarisation perpendiculaire
Correct answer: B — Une polarisation circulaire. Question tirée de la banque officielle d'ISDE.
Why
When two dipoles are crossed and fed with signals 90 degrees out of phase, the resulting radio wave rotates as it travels, creating a corkscrew motion known as circular polarization. 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.
Drill A-007 — free, no account