The goal of this project is to build a small very low power RF transmitter. It will reflect RF ambient power to transmit data.
This module can be able used to operate during a very long period of time in harsh environment, like space or high mountain. It's also a way to use the RF fog of our city to do something useful.
The RF Energy can be provided by harvesting a strong signal already present, or by using a highly directional antenna pointed to the sensor and a power amplifier.
It works the same way as RFID, but the range will be higher, a few kilometers.
The module will be a small pcb of 1cmx2cm with castellated holes on the side. It will have one onboard microcontroller, and one RF input/output. The controller will have most of it io/pins wired to the castellated holes, to be able to acquire directly data from external sensors or computer.
I need to find a better way to switch the two impedances.
So I will try with a MOSFET, and also another model of pin diode, but new this time to avoid any problem.
When I will receive them, I will be able to first test with a VNA that I have a consistent impedance switching, and then I will start to make a frequency generator and do the first RF backscatter experiments.
Then I will be able to choose the best uC suited for this task.
When I receive the parts, I will post again.