Post subject: Gap between the stripline trace
and ground trace
Unread postPosted: Thu Jan 20, 2005 6:31 am
I understand from the replies that I got for my posting
on 14th of Jan that the rule of thumb that I am following on the
gap between the microstrip trace and ground trace is acceptable.
For reference, I am repeating below the lines I had posted.
[If 'W' is the width of the microstrip line, maintaining a gap
of 'W' between the microstrip line and ground trace/plane next to
it on the same layer is considered as good RF practice. Am I right
on this thumb rule? ]
Now, I would like to know if the above
rule of thumb holds good for stripline as well. Have in mind that
the width of stripline is almost five times lesser compared to microstripline
for given substrate and charecteristic impedance. For 50 ohms line
impedance and Rogers RO4003C, trace width for microstrip is 44 mils
and for stripline it is around 9 mils.
Post subject: Rule of thumb
Fri Jan 21, 2005 9:05 am
You can save yourself a lot of
time and aggrevation by going on the microwave office website and
downloading their "free" transmission line calculator.
Post subject: Re: Gap between the
stripline trace and ground trace
Unread postPosted: Fri Jul 01,
2005 11:31 am
The rules of thumb I use for RO4003 is to
use a dielectric constant of 3.6 when calculating coplanar waveguide
etc. and use APPCad (Free) from Agilent.
I have produced boards
with runs up to 18"long, going through blind vias that are "flat"
to about 10GHz and -3db at 14GHz. Also for coplarnar wave guide,
you must take into account ground planes and core thickness. Get
the program and don't putz around with rules of thumb with 4003
there really are none except for the adjustment of the constant,(which
came from a Rogers Application Engineer).
Unread postPosted: Fri Jul 01, 2005
Mon Jun 27, 2005 2:02 pm
This is what that programs are made up for, to provide you with
the exact dimensions of the transmission lines and required gaps.
Use these tools and you will save yourself an unneccessary spin
of PCB layout.