NEC-LIST: GPR antennas

Pascale :
 
I would suggest to use a ferrite-loaded dipole. For example, use
low-loss Nickel-Zinc (Ni-Zn) ferrite bars, 10 - 20 mm thick, embedded
in an Aluminum channel of dipole length. The Ni-Zn ferrite should have
a permeability of between 100 and 50 over the frequency range of 5-50
MHz.
 
My estimate is that you could reduce the dipole length by a ratio of
3-5, i.e., at 8 MHz from 12.5 m to 2.5 to 3.5 m.
 
There are Ni-Zn ferrites with fairly high permeability up to
approximately 100 MHz. Depending on the average power to the antenna,
you want a low loss tangent.
 
Bonne Chance !
 
Max J. Schmitt
Cons.Eng.
Received on Fri Mar 31 2000 - 06:44:35 EST