Very broadband antenna systems, such as log-periodics, are still resonant.
They are a collection of different-frequency resonant elements.

Another way of looking at it, a collection is broadband because as a whole
it has a very low resonant Q.

Resonant circuits have an effective Q or a collection of Q values even when
the impedance-frequency response is flat-topped. (As inside a double-tuned
455 KHz IF transformer can.)

At sufficiently high and sufficiently low frequencies the reactive component
of the input impedance always predominates.

The definition of resonance as being adjusted to present a resistive load to
the transmitter should not infringed.

Of course, it is quite possible to operate a transmitter with a non-resonant
load, ie., the load impedance having a reactive component in addition to the
essential resistive load. But if only for economic reasons this condition is
nearly always avoided.
----
Reg.

=======================================

"Dave Shrader" There's a world of difference between a resonant antenna
and a resonant
antenna system!!

BTW, is a Log Periodic Antenna, example Tennadyne T8, resonant across
the frequency range of 13.5 MHz to 30 MHz?? No tuning required on any
frequency between 13.5 and 30 MHz, and VSWR 1.7:1 across the range!

Deacon Dave, W1MCE
+ + +
Reg Edwards wrote:

What's all this stuff about resonant antennas? Some great antenna
designs

do

not use a resonant length.



All antenna 'systems' are resonant because they all present a resistive
load
to the transmitter. QED.