[SI-LIST] uStrip question

  • From: "bdempsey85" <bdempsey85@xxxxxxxxxxx>
  • To: <si-list@xxxxxxxxxxxxx>
  • Date: Mon, 8 Mar 2004 20:42:03 -0600

I recently built 3 different uStrip construction testboards and was
surprised by the results: it didn=92t work!

I built two boards as trace over copper with soldermask  and one board
as a co-planar waveguide.  I constructed the geometries of the boards by
following the results of some =93freebie=94 tools out there.

After the boards were built I connected them to an HP network analyzer
(I calibrated out the cables/cons) to look at S21 response.  What I
found was surprising.  The S21 was extremely poor:  approx 6.5dB loss
over 4=94.  This just does not compare to the results of the tools I =
access to.  I expected about 1.2 =96 1.5 dB of loss at this frequency.

Has anyone else out there had some =93bad=94 experiences with uStrip @
2.5GHz?  What tools are you using?  How are you correlating your =
results to real-world?

The construction of the three boards was as follows:

Board 1: 12 mil trace, =BD oz foil with 1 oz plating, 8 mil to gnd =
sheets of 1080 prepreg), 1oz copper gnd

Board 2: (CPW): 8 mil trace, 8 mils to gnd (again, 3 sheets of 1080
prepreg), 6 mil to gnd return on signal layer, same plating/thicknesses

Board 3: 4.75 mil trace, ~2.83 mils to gnd (one sheet of 1080 prepreg),
=BD foil, 1oz plating, 1oz copper gnd



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