Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
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My Hobby Website:
1700-1900MHz 20w RF amp - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: 1700-1900MHz 20w RF amp Posted: Thu Jan 15, 2009
Joined: Tue Aug 26, 2008 5:18 am
can any one advise me which transistors
are available for designing 20w, 24-28V balanced RF amp to cover 1.7-1.9GHz
band. I am using Microwave Office so it will be nice to have a device
whose model is available in MWO like freescale.
Post subject: Re: 1700-1900MHz 20w RF ampPosted:
Fri Jan 30, 2009 5:10 pm
Joined: Mon Jun
27, 2005 2:02 pm
Take a look at Infineon line of RF Power Transistors.
http://www.infineon.com/cms/en/product/ ... Power.html
recent experience with them, I know they also have models for MWO.
Post subject: Re: 1700-1900MHz 20w
RF ampPosted: Thu Feb 19, 2009 6:47 am
Tue Aug 26, 2008 5:18 am
Thanks for your reply. I've designed 20W PA (balanced Class A) operating
from 1700MHz to 1900MHz using MRF19030 Transistors from Freescale.
Re: 1700-1900MHz 20w RF ampPosted: Mon Mar 30, 2009 4:52 pm
Just to add some thoughts to your selection:
MRF19030 transistor form Freescale might be obsolete or in the way,
perhaps you want to take a look to the Freescale 5th or 6th generation
LDMOS amplifiers (MRF5... MRF6...) they are more efficient and rough
(difficult to burn by a fair output load).
Also, you asked for a
Class A operation, these Freescale transistors were designed to work
as Class AB... I think if you try to make it work into a Class A operation
you might end up having a lower P1dB.
-A 30W transistor for 20W
sound like a good choice from the fact that you will have to use a very
broad band match (many match stages---> more insertion loss) to meet
the specs from 1.7 to 1.9GHz.
-Remember to add a circuit to compensate
the bias point drift over temperature, specially if you plan to use
it in a high bias point where you will have a lot of heat generation
( I assumed this from the fact that you asked for a class A amp) .