The choice for 2-18GHz was microstrip on Duroid...at REMEC and RF
Microsystems.... When I left they were talking about doing some work in the
40GHz range, but I never saw what became of that...My guess is that at the
higher frequencies, temperature stability and moisture susceptibility would
play a big part in the design due to the TCE of the materials and
maintaining some sort of real stability would be the challenge.
You would probably need to pick very stable materials for the substrate and
adjust the thickness of it such that the features you wished to etch were of
sufficient physical size to preclude extra special treatment for the etching
process. I know we targeted the line width to be around 22 mils for a 50 ohm
line...If you're making edge coupled filters, or mixers, etc, you may run
into line widths as small as 3-5 mils... that can run against the etching
limitations of most manufacturers...
It's all a function of the base material dielectric and it's thickness...
well there's more to it than that...(but that's classified...)
Edge mount connectors need some impedance matching at the connection point,
typically tuning tabs are used... I have seen some SMA's that are designed
to work up to the 40GHz range....
Cost effective materials would be Rogers RO3003, 3006, 3010 and the low
moisture versions, about 16.00 a sq. ft....available from
www.rogers-corp.com
I have done parallel edge connector transitions and right angle transitions
with N-type, SMC, SMA, SMB's and more... I still think microstrip is the
simplest most cost effective method... not to say it can't be done
otherwise... :)
- Bill Brooks
-----Original Message-----
From: Tracy Black [mailto:[log in to unmask]]
Sent: Thursday, June 15, 2000 12:53 PM
To: [log in to unmask]
Subject: [TN] PCB trace at high freq.
Hi guys:
I was asked an interesting question by a customer. That was what "trace
design" do most people prefer when the operating frequency is the range of
20-30GHz; i.e. Stripline, micro-strip, or other type of configuration.
Does that change for an edge mount?
Regards,
Tracy Black
Engineer
Microwave Engineering
Phone: 623-245-1050 xt 437
Fax: 623-934-5160
E-Mail: [log in to unmask]
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