Low power sensor nodes distributed over a large geographical area provide an economical way to collect environmental
information. The sensors can utilize backscatter signals to communicate with a central node without
significant power consumption. Each sensor can modulate its reflected backscatter signal by switching a load on
the sensor antenna. This allows design of low power sensor nodes with longer lasting battery life. The nodes can
be built to reradiate a harmonic of the received signal. This helps to avoid interference at the central node from
reflection from unwanted objects.
A passive harmonic reradiator is designed in this project to receive a 915 MHz electromagnetic wave and
reradiate at 1.83 GHz. The design consists of receiver antenna, transmitter antenna, a Schottky diode, and
matching network. Simulation and measurement results are provided. The results show promising characteristics
for the use of the device to track animals in wild life.
Behnam Jamali, Behnam Jamali,
"A passive harmonic reradiator tag for animal tracking", Proc. SPIE 7268, Smart Structures, Devices, and Systems IV, 72681B (30 December 2008); doi: 10.1117/12.810699; https://doi.org/10.1117/12.810699