I am designing a novel circuit that I beleive has not been constructed yet! No -- I'm just using an exotic switching device for a class E amplifier.

My operating frequency is close to the 160 ham band (my target is between 1 and 2 megahertz).

I have seen multiple designs for bands closer to 80 meters (a few megahertz) that use a 47 uH RF choke on the drain of a mosfet. I will be winding this inductor myself so I would like to optimize this value and determine its effect on the output matching circuit.

I have an LCR meter and I am operating this amplifier at a bandwidth not exceeding 10kHz.

Have a schematic (I see this is for 160m and has a larger inductor):

160m schematic

Do I have to know my load impedance before selecting the RF choke or is that load independent? (as a side note I am using Cree SiC power mosfets because I have a source...)

  • \$\begingroup\$ How about links or pictures of the schematic? \$\endgroup\$
    – Andy aka
    Mar 4 '14 at 8:25
  • \$\begingroup\$ I have a QRP transceiver that uses a controller to create a SSB signal with a class e amplifier, it goes from 80m to 10m bands with the same choke, around 5Watt out with an efficiency of around 75% to 92%. I suppose the tank circuit is the important part and the choke has little to no influence. 73 de oe6ccp Erich \$\endgroup\$
    – Erich
    Oct 13 at 22:41

I already implemented this topology in the past.

I had the chance to collaborate directly with the inventor of the technology, Nathan O. Sokal, but fortunately you don't need to because references are available.

The most useful document about this class E topology to design and tune our amplifier was the following paper: Class-E RF Power Amplifiers. It contains all the design equations required.


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