Return-Path: Received: (qmail 10025 invoked from network); 20 Aug 1999 07:41:00 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 20 Aug 1999 07:41:00 +0100 Received: (qmail 21082 invoked from network); 20 Aug 1999 06:45:23 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 20 Aug 1999 06:45:23 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11Hi9X-0001SO-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 20 Aug 1999 07:27:51 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from nms.rz.uni-kiel.de ([134.245.1.2]) by post.thorcom.com with smtp (Exim 3.02 #1) id 11Hi9X-0001SH-00 for rsgb_lf_group@blacksheep.org; Fri, 20 Aug 1999 07:27:51 +0100 Received: from srv1.mail.uni-kiel.de by nms.rz.uni-kiel.de with Local-SMTP (PP); Fri, 20 Aug 1999 08:27:16 +0200 Received: from nephro.uni-kiel.de (PC108110.dial.uni-kiel.de [134.245.108.110]) by srv1.mail.uni-kiel.de (8.9.1b+Sun/8.9.1) with ESMTP id IAA01145 for ; Fri, 20 Aug 1999 08:27:33 +0200 (MET DST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: <37BCF53B.E48012A6@nephro.uni-kiel.de> Date: Fri, 20 Aug 1999 08:27:07 +0200 From: "Peter W. Schnoor" Organization: University of Kiel, Clinic of Nephrology X-Mailer: Mozilla 4.05 [en] (X11; I; Linux 2.0.33 i586) To: rsgb_lf_group@blacksheep.org Subject: Re: LF: high power class E transmitter References: <3.0.1.16.19990819144455.3d4776e4@mail.cc.kuleuven.ac.be> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: Hello Group, Hi Rik, Rik Strobbe wrote: > > Charmed by the simplicity (only 4 components) and the high efficiency of > class E amplifiers I decided to do some experiments with these. Not at power levels >200Watts. > So I wonder if someone already has experience with a high-power class E > amplifier ? I know this article. Running class-E is not a question of high voltage at first. Class-E means to load a current fed switch (here MOSFet and choke) such that Ud AND dUd/dt at switching time are BOTH zero ("soft landing"). This is the key to class-E! So you have to deal with impedance i.e. "right" phase shifts at input of your output network. What kind of output circuit you want to use doesn't matter if it provides "soft landing". Of course this is easier to achieve at somewhat higher voltages. Class-E designs are very robust since of it's high capacitance at load. I killed most Fets from Gate side (Ugmax +-20V...). I observed the following: One disadvantage is that due to the low resonance frequencies of the output filter circuits the class-E design has a tendency to "stutter" on sub harmonics if mismatched to the "inductance plane" of the smith diagram. But I never observed this, mismatching the PA resistively only. I collected some other articles on class-D/E (the well known QST article included) there: ftp://ftp.rz.uni-kiel.de/pub/nephro/nephlab/lp/MosFet-PA/ Look for: ClassE.pdf, PA_10MHz.pdf, QST.pdf, RFdesign.pdf. (Acrobat Reader or clone required...) 54°16'N / 10°04'E, JO54ag 73 es gl de Peter, DF3LP