[AMPS] interesting SS amps

[measures]

PAA12514
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>
>Dr. Hiroaki Ikeda in Tokyo has been a long time developer of high
>power solid state amplifiers for broadcast. I met him in 1980, at a
>conference, when he was pushing MOSFETS from Hitachi and NEC  to
>deliver RF power for MW frequencies. He worked for the Japanese
>Broadcasting Corp (NHK) and was a professor at Shizuoka Univ until
>1998. His transmitter work was published in IEEE Transactions on
>Broadcast in Dec 1980 and in Proc IEE International Broadcasting
>Convention, 1980. Also more RF developments with FETs in several
>Transactions of IEE Japan in 1986.
>
>In December 1999, Ikeda published a paper in IEEE Trans. on
>Industrial Electronics titled:
>Megasonic Transducer Drive Utilizing MOSFET DC-to-RF Inverter with
>Output Power of 600 W at 1 MHz. For those trying to push RF MOSFETS
>and combine them in Class D, check this out. They use the RF to drive
>a cleaner for LCDs and semiconductor wafers.
>
>In an unrelated but similar (!) set if papers, H. Fujita presents
>work on a 2 KW 2 MHz RF system, using MOSFETS to drive a low
>temperature plasma for surface treatment. This is in IEEE Trans on
>Power Electronics, Nov 1999 and in IEEE Trans on Industry
>Applications, Jan 1999. He uses a third harmonic resonant circuit in
>the load to help square up the waveforms in the FETS to lower losses
>and surges/spikes.
>
>Just wanted to point out that a lot of interesting high power RF
>stuff is done under the guise of 'industry' applications, not just in
>medical, communications, or scientific work as most of us are
>familiar. Although this isn't 28 MHZ stuff, and it certainly isn't
>linear, the circuit evaluation and the combiner techniques are of
>interest.
>
€  If the radio world had been using solid-state amps since the very
beginning, and a small company in San Bruno announced that it had
developed a much more efficient, HF linear-amplifying device that
operated from 22kV at 45A  (the 8973 tetrode),  that operated in
high-temp enviorens, what then?   Would the electron-tube be hailed as a
monumental technical breakthrough?

-  Rich..., 805.386.3734, www.vcnet.com/measures.
end


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