Class E Power Amplifier

[khouly]

i want to design class E power Amlifier for 900 Mhz application , and i want to know where to start ,
so please recommend a book , or paper to begin with

and i saw most of the class E amps use LDMOS or CMOS , or HBT , what about biploar devices are they used in this class

and also i want to ask how to select the bias point of the gate or the base


thanks in advance

khouly

 

[toonafishy]

Search for Sokal and/or Raab. They wrote the book Solid State Radio Engineering and they are big in Class E.

for instance:

h**p://www.avtechpulse.com/papers/classe/

 

[drabos]

you can use bipolar decices.

But FETs are more useful for switch-mode devices.
Bipolar devices go to deep saturation, it will make slower they operation.

 

[khouly]

i have seen class E amps based on LDMOS devices , i will try to get a model of one , and begin to design using the LDMOS

khouly

 

[unkarc]

Hi,

You may collect some useful info from these papers, all deal with 900MHz Class-E PAs:

http://scholar.lib.vt.edu/theses/available/etd-07152001-172453/unrestricted/Chap6.PDF
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[khouly]

what about the base bias of the transistor if i use Bjt will be like class AB or just put the input wave form in the base

khouly

 

[unkarc]

The latter case: no any bias as much as a Class AB bias, only just a little (say 0.2-0.3V DC, definitely not causing any collector current) to easy the RF drive at 900MHz, this helps the obviously not so rapid rise time of the drive pulse.