On 9/14/2015 12:06 PM, gareth wrote:
"rickman" wrote in message
...
On 9/14/2015 11:14 AM, gareth wrote:
Taking one's cue from the Alford Slot Antenna, let us propose the use of
the
fields in
the air gap of a parallel plate capacitor as the source of RF radiation.

To do this, we will terminate our 50 ohm coax with a series LC circuit of
50
ohm
resistive impedances (so one will be 25+jX and the other 25-jX) at the
operating
frequency.

I think your intent and your values don't correspond. The +jX and -jX
terms are correct for the imaginary parts of the impedances, but you don't
want the capacitor and inductor to have 25 ohms each of dissipative, real
resistance do you? That would leave nothing for the transmission
resistance if you were to radiate any energy. So either you would be
designing an antenna at other than 50 ohms impedance, or you are trying to
design an antenna which doesn't radiate.

Oops! Yes, of course you are right; too much typing and not enough thought
:-)

What I was trying to picture was a series LC circuit presenting a
non-reacitve
impedance of 50 ohms.

So should I assume you intended to say the capacitor and inductor have
complex impedances of 0 ± jX ohms are are in series with the 50 ohm
radiation resistance? Or do you want the antenna to have a lower
impedance than 50 ohms?

--

Rick