Richard Fry wrote:
On Sep 23, 1:12 pm, Szczepan Białek wrote:
The simplest dipole is a transmissing line (the two wires).
Not so.
A transmission line with balanced currents is not a dipole, and does
not / cannot produce the radiated fields of a dipole.
Yes, no matter what the conditions on an ideal transmission
line, the two currents are equal in magnitude and opposite
phase. Therefore, zero radiation from an ideal transmission
line.
At the ends of a 1/2WL dipole, the forward current and
reflected currents are equal in amplitude and opposite
phase. Therefore, destructive interference with no
radiation.
At the center of a 1/2WL dipole, the forward current
and reflected current are in phase and interfere
constructively. Therefore, RADIATION!
--
73, Cecil, IEEE, OOTC,
http://www.w5dxp.com