Resonant condition
On Jun 7, 11:48*am, Cecil Moore wrote:
For instance, the following shortened stub has a resonant frequency at
which it is electrically 1/4WL long even though it is only 1/8WL long
physically because of the 45 degree phase shift between the two
sections. ...
Are you stating that such a radiator with a physical length of 1/8-
lambda has ALL of the electrical characteristics of a self-resonant,
1/4-wave radiator -- including its radiation resistance, radiation
pattern, and peak gain in dBi?
Zero reactance at the input terminals of an electrically short
radiator does not mean that such a radiator is the electrical equal of
every other radiator with zero reactance at its input terminals.
Zero input reactance for short radiators can be attained by various
means, but the intrinsic, real radiation resistance/pattern/gain of an
antenna is a function of the electrical length, configuration, and
installation environment of the conductor(s) exposed to free space,
regardless of the reactance at the feedpoint -- whether that reactance
is zero or not.
RF
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