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Is this dipole a balanced or unbalanced antenna?

huytergan

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I wonder can we call this clover inspired crossed dipolea antenna balanced or unbalanced.
Since the coax's inner conductor feeds the one of top clovers, and the outer conductor (which's also grounded) feeds the diagonal clover of it at bottom of the substrate. (the other clovers at the other diagonal has the similar feeding.)
Can we say this's unbalanced antenna? since the clovers' (on one diagonal) feed points are not symmetric

QLr3G.jpg


KR
 
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FvM

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Surely not fully balanced, but the actual asymmetry depends on the permeability of the ferrite disc which blocks sheet currents more or less. With an ideal common mode choke, it's perfectly balanced.
 

huytergan

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Surely not fully balanced, but the actual asymmetry depends on the permeability of the ferrite disc which blocks sheet currents more or less. With an ideal common mode choke, it's perfectly balanced.
Thanks, when you say "Not fully balanced" you mean it because of the feed points on the antenna, right? Since we know the coax is unbalanced, I wonder whether a balun is needed or not. So if it's not fully balanced, a balun is not a need since the feeder (coax) is already unbalanced? It says the ferrite has a permeability of 10 while the permittivity is 10 too.
 
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biff44

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you would need to add a sleeve type balun in the coax cable portion for it to be truly balanced.
since there is not balun, your signals will NOT be truly differential, and only approximate it.
you could add some ferrite beads to the outside of the coax cable, so outside surface ground currents are suppressed, and will not affect the radiation pattern as much
 

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