Dear All

I would like some advice on the testing of Surface Acoustic Wave (SAW) sensors.
My 120 MHz devices are gold wire-bonded into a metal chip header, and mounted on
a shielded PCB, for testing with a network analyser.  The analyser is calibrated
down to the wire bond level.  I would like to know the following:

1:  The background level rises 70dB from 20kHz to 200MHz, levelling out at the
upper frequencies.  Why might this be?

2: SAW behaviour exists at the correct frequency, but with small fluctuations
around 4dB high over approx 5MHz, not a strong peak.    What could the cause be?
The peak is not strong enough for sensing purposes!

Any answers to these questions, or any basic advice or literature on the testing
of SAW devices would be useful !

Thanks,

Andrew Turton

School of Engineering
University of Durham
South Road
Durham
DH1 3LE
ENGLAND

e-mail: a.c.turton@durham.ac.uk
Tel.  +44 191 334 2525
Fax. +44 191 334 2407