Specifications

5.6. DESIGN EVALUATION
Figure 5.13: Received waveform from an RFID transponder
the claims made in the article. Maximum read range was approximately
100mm when using a single antenna as a transmitter and a receiver.
Large Single Square 400µH Loop The performance of this antenna
( 280mm x 240mm) was similar to the small round lo op mentioned above,
with one exception: although the maximum read range remained at approximately
100mm, the area over which the system worked was greatly improved. Reliable
reception was possible over the full area of the antenna as well as a surrounding
radius of approximately 100mm, provided the orientation of the transponder
remained correct relative to the antenna.
Large Square 27µH Loop Transmitter and Large Square 400µH
Loop Receiver In this test, separate antennae were used for transmitting
and receiving. Power requirements for the transmitter increased (as expected
with a reduced inductance and constant switching voltage), but range and
operating area increased. The primary reason for the increased range was
the additional number of turns on the receiving antenna. It thus became
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