Hi, everyone!
Does anyone know of a timely reference on Class E RF amplifiers?
All I can seem to find are:
The 1997 May-June QST article using a non-optimum FET... and
vastly exceeding the current ratings of dipped mica capacitors.
An ancient October 1974 Ham Radio article.
& searching on the 'net...
http://eea099.ee.ust.hk/HF/_private/HF_notes/Ch7.htm
plus
http://www.avtechpulse.com/papers/classe/
which included some dated references:
I also looked at the original patent by Sokal & Sokal but, that work
was done way before FET's were good enough to make this scheme really
work!
I think that the components have just about made it to the point where
it is possible to build a legal limit HF linear amplifier using this
topology plus an envelope elimination and restoration system with an
overall efficiency of say... 75%.
I massaged the design formulas a bit in an Excel spreadsheet and it
appears that with a 200V Drain supply and a 12.5 ohm "working" impedance,
that could be transformed up to 50 ohms with a 4:1 balun, a 1500 watt
output is realizable with reasonable tank circuit components.
One really interesting feature is that the FET Drain capacitance
variation with voltage seems to work "in favor" with this topology.
What a pleasant surprise, after all those laws of physics and man working
against us for so long! :-)
Happy New Year & 73,
Marv WC6W
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