Differences Between NEC-2, NEC-1, and AMP2
The following ar features of the NEC-1 code that differ from AMP2:
- A new current expansion is used with continuous current and current
derivative along wires. The expansion enforces a new condition at multiple-wire
junctions and allows for current flowing onto the end cap at an open wire end
- Where a wire connects to a surface, the surface-current expansion is
related to the current at the base of the wire rather than at the center of the
last wire segment.
- An optional voltage source based on a discontinuity in current slope is
- In the thin-wire approximation, the current filament is on the wire axis
and the observation points are on the surface.
- An optional extended thin-wire approximation is available.
- Either a perfectly or imperfectly conducting ground may be used with
- Either a perfect or imperfect ground may be used in incident plane wave.
- Some constants have been changed including the velocity of light (2.998*108m/sec.)
and the default frequency (299.8 MHz)
- The wire-segment connection numbers have new meanings.
- The radiated field is the field at a range R multiplied by R with R
approaching infinity. In AMP and AMP2, the field is multiplied by R/lamda).
- Both near electric and magnetic fields may be computed. The NF card is no
- Charge density may be printed for wires.
- The PT card is no longer cancelled by a new EX card.
The following are features of NEC-2 that differ from NEC-1:
- The NGF option has been added.
- The restart option has been removed.
- The Sommerfeld/Norton method has been added.
- Maximum coupling between antennas may be computed.
- wires may have tapered radius and segment lengths
- Patches may be specified as triangles, rectangles, or quadrangles.
- Rectangular surfaces with multiple patches may be specified.
- The SS card for surfaces has been eliminated.
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