Rf = free space impedence (small for small loops)
Rs = skin effect resistance (depends on bulk resistivity, usable skin area,
frequency)
Efficiency = Rf / (Rf + Rs)
You can see as Rs approaches zero efficiency approaches 1 and as Rs equals
Rf efficiency is halved.
Note that in addition to skin effect other resistances could be in an actual
implementation such as the resistance of joints to construct the loop,
connection to the capacitor and the implementation of the capacitor itself.
All those would add to Rs and further degrade the efficiency.
73
jim ab3cv
