Dear all,

I am setting up a MEMs test facility and need to measure devices at
frequencies up to 80MHz. I have little experience of measurements at
higher frequencies and was hoping to find someone to talk to with a little
more experience. I have access to a probe station (Suss PM5), an agilent
function generator (33250A) and a scope (agilent infiniuum) and am just
trying to see whether the (passive) probes are suitable for measurements
up to 80MHz. I thought that provided the unshielded length of the
connection at the tip of the probe was significantly less than
1/4 of a wavelength (about 1cm at 80MHz), and that the device itself was
small, I could get away with treating the device as quasi DC. However
initial experiments in which a frequency sweep is measured through 2
shorted probes show a distinctly non-linear response above 1MHz. Can
anyone tell me whether I need to buy active probes for this frequency
range? Does anyone have experience of making measurements at similar
frequencies?

Thanks,

James

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Dr James Ransley
jhtr2@cam.ac.uk

Cambridge University Nanoscience Centre
J. J. Thomson Avenue
West Cambridge
CB3 0FF
United Kingdom

Phone:  +44 (0) 1223 760313
Fax:    +44 (0) 1223 760309
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