Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
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.