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Below are all of the forum threads, including all
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Post subject: TEM alternate
Posted: Thu Sep 29, 2005 10:53 am
I saw an interesting question on another forum (won't
mention since probably against policy) that I'd like to
"As an alternate to a TEM cell, we're
exploring the idea of using a waveguide-below-cutoff as a
means of creating a controlled environment for receiver
sensitivity measurements. The receiver is within
cellphone-sized package and contains a loop antenna. The
receive frequency is roughly 900 MHz.
is to construct a simple tubular rectangular metal
structure with height and width dimensions appropriate to
prevent waveguide propagation, supposedly providing a
steep attenuation characteristic to an incident field at
900 MHz. One end of the tube would be open and allow
placement of the receiver in a tightly controlled position
within the tube. The other end of the tube would be closed
off by a metal plate containing a panel-mount coaxial
connector attached by cable to a signal generator.
The thought is to terminate the other end of the
connector with some sort of a load appropriate to the
generator (50 ohm wirewound resistor?) creating a field
within the tube that would rapidly decay.
generator level, length of the tube, and position of the
receiver within the tube would be experimentally
determined (using a known good receiver) to be appropriate
for threshold testing of subsequent receivers.
the concept have merit? Any comments/suggestions would be