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RF TRANSMITTER LAYOUT - RF Cafe Forums
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deepak007
Post subject: RF TRANSMITTER LAYOUT Posted: Fri Jul 25,
2008 2:45 pm
Lieutenant
Joined: Sun Jun 22, 2008 3:57
am
Posts: 4
hello
i am a beginner to CAD. i have designed
a layout for a rf video tx circuit. i am enclosing the schematic and
layout. please tell me if there are any errors. i used a longer trace
to connect L2 to T1. will it have any effect on L2 inductance? please
give me suggestions on how to make it better. [img][img]http://img93.imageshack.us/img93/7151/rflayoutsd4.th.jpg[/img][/img]
Top
nubbage
Post subject: Posted: Mon Jul 28, 2008
5:46 am
General
Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
Hi deepak
A track length of
about 35 mm and 0.5mm wide (estimates from your pdf file) will add about
0.4 microhenry to L2.
I gave you an extensive reply to this design
on June 30th. Was this understood and followed?
Essentially, all
of the RF side of the circuit should be ground on both sides of the
PCB, with pads for components. Conventional LF electronic layout, as
done by software, leads to many problems at RF. Much of this is due
to narrow track widths give rise to higher radiated fields and so increase
the RF coupling into parts that should not be coupled to. Thus the true
schematic model with narrow tracks would have many many mutual inductances
that give rise to spurious genrated frequencies. Best avoided.
Posted 11/12/2012
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