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
Mail" when a new message arrived...
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and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
Gap between the stripline trace and ground trace - 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: Gap between the stripline trace and
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
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)
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 1:05 pm
Joined: 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.