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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My Hobby Website:
Mircostrip highpass filter - 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: Mircostrip highpass filter
Wed Jan 12, 2005 7:31 am
Nov 15, 2004 4:08 pm
I am working on a highpass
microstrip filter for stop frequency 40GHz on substrate:
The idea is that, one edge of the microstrip
is shorted to the groundplane which ensures, that DC and TEM, qTEM modes
are disabled in the structure.
Has anyone came across the problem??
Post subject: 40GHz high pass
Wed Jan 12, 2005 11:14 am
0.254mm=10mil, the circuit would nbever
work with 100mil thick substrate. The dominate mode in microstrip transmission
is quasi TEM (qTEM) so definetly do not want to squash that mode. There
are surface modes which need to supressed, especially at the higher
frequencise. If you have a board that you are testing then you will
need to wrap the ground plane around the edge or stitch vias to ground.
If this is part of a larger board then you will want ground plane at
the surface ~3-4 times the transmission line width away from the transmission
line. This will help suprress the surface modes. You do not want the
ground plane to close the transmission line or it willbegin to look
coplanar and the impedance will change.