NEC-LIST: Near field

I'm modelling radiation patterns of a dipole using the near field
option of NEC-2 (NE and NH cards). The dipole is 1m long and is
situated either in free space or above a ground (Epsr=3.5 and
sigma=5mS/m). The frequencies are 150 MHz or 100 MHz.

I wonder if there is a maximal distance from the dipole beyond which
the calculated fields are inacurate. It's usual to consider that the
near/far field distance is : D=2*L*L/l where L is the dipole lenght
and l is the wavelenght (l=2*L, so D=L ?). However Turner ("Modelling
antenna-ground interactions", 1994) calculated the field of a dipole
0.5m long until 10m.

I would like to know what maximal distance from the dipole we can
admit when modelling patterns using the NE card.

Thanks for your usual co-operation.
Best regards.

Lutz Pascale

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| Pascale LUTZ | e-mail : pascale.lutz_at_univ-pau.fr |
| Laboratoire d'Imagerie Geophysique | |
| Universite de Pau | Tel: 33 (0)5 59 92 31 74 |
| et des Pays de l'Adour | Fax: 33 (0)5 59 92 31 86 |
| Avenue de l'Universite | |
| 64000 Pau | |
| France | |
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Received on Mon Jun 19 2000 - 07:27:24 EDT