Marconi’s experiment and invention in the field of wireless radio communication over several decades ago to improvements in wireless radio till now has led to connecting over 6 billion mobile subscribers in the world today while enabling data to be sent from deep space such as from Pluto and Voyager Space craft. The next growth in communication would be in connecting things in the IoT sphere. IoT offers exciting opportunities for all but it suffers from lots of challenges including security, battery life, range of communication, cost among others.
Researchers at Stanford university have developed what could showcase how a battery-less radios can work.In the first phase of the project the researchers have demonstrated a working single-chip 24GHz/60GHz passive radio implemented in 65nm CMOS chip. This chip is fully self-sufficient in its power needs with no pads or any external components (e.g. power supply) as it generates the required power from the signal it receives. The chip also integrates RX and TX antennas and provides a communication range of up to 50 cm during the initial phase. A M-PPM 60GHz transmitter (6-bits per slot) is used to communicate data sequence as well as the local timing reference. Pulse signaling enables real-time localization through time-of-flight. The chip operates with a standby recovered power of less than 1.5uW coming from the reader.
The researchers face unique challenges in addressing the need for sufficient data rate without using a power supply. However, there are several key challenges that still need to be addressed in this area. Cost (dominated by antenna board and interface), number of readable transponders (and latency in doing so), data-rate capacity, localization and miniaturization are the issues faced by today’s designers. Addressing these challenges will open up new application areas for IoT.