Guest Post subject: Gain expansion Unread postPosted: Fri Jul
15, 2005 2:04 am Hello, In a three stage amplifier that I
have designed (pHEMTs as active devices), I am noticing an substantial
gain increase (about 3 dB) with input power. The small signal gain is
down 4 dB from the simulated value but starts to go up with input power
before the gain starts to compress. The gain 'expansion' is also so
steep it almost looks like there is a discontinuity in the Gain/Pin
curves. Return losses are close to simulated values. Any ideas on what
might be causing this? Top IR Post subject:
Unread postPosted: Fri Jul 15, 2005 2:43 am Offline Site Admin
User avatar Joined: Mon Jun 27, 2005 2:02 pm Posts: 373
Location: Germany Hello, The situation you described is common
in several transistor technologies. It is mostly related to bias level
the transistor gets and can be emphasized or de-emphasized with lower
or higher bias respectively. This gain expansion as gain compression
is considered as non-linearity. You can make this useful, if
you plan to use some sort of of linearization scheme for your amplifier.
_________________ Best regards, - IR Top
Profile IR Post subject: Unread postPosted: Mon Jul
18, 2005 12:53 pm Offline Site Admin User avatar Joined:
Mon Jun 27, 2005 2:02 pm Posts: 373 Location: Germany Just
a clarification to my previous post: By bias level, I meant for example
the Vgs voltage level in JFET's/MESFET's _________________
Best regards, - IR Posted
11/12/2012
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