UHF Energy Harvesting Radio System Physical and MAC Layer Considerations
Xiaohu Zhang, Kansas State University, 2009
By using the energy emitted by the sun, it should be possible to create a communication device that can be remotely solar-powered. This was the idea behind the Energy Harvesting project pursued by former graduate student Xiaohu Zhang.
To supply the energy needed to power and drive the device, solar cells used in common, handheld calculators were implemented on the device. Simple tests verified the operation of these cells.
The project resulted in the production of a solar-powered communication demoboard, pictured below. The communication IC, which is responsible for the transmission of RF signals, was designed by Ph.D. students and professors at KSU.
It was necessary to confirm that the testboard was indeed communicating properly. So, using test equipment rated to Microwave frequencies, the performance of the device was substantiated. The media below document parts of this process.
The "dummy data" seen on this oscilloscope
is the result of preparing the test environment.
The video above is this audible signal.
The gray signal pictured here
represents the 60-bit initialization
sequence needed to program
the PIC used on the testboard.
The green signal is the RFIC
on the board, responding to the
Characterizing the Performance
The images below summarize the performance of the testboard.
This plot shows the calculated transmit
power vs. the distance away from the
receiver, at 2.4 GHz.
This image compares the
different ranges and
powers for differing frequencies
of operation as measured from