In the IoT world when all things are networked, radio communication transceivers providing network access will need to be cheap, very discreet and require very little power. At the recent VLSI Technology and Circuits Symposium held in Hawaii assistant professor of electrical engineering Amin Arbabian from Stanford University demonstrated a tiny self-contained chip developed in collaboration with the University of California Berkeley.
Operation of the device seems to be similar to RFID tag technology where the tag is energized by an external RF signal and then responds by transmitting its unique address using energy harvested from the external RF signal. This new device has more processing power than the simpler RFID devices, allowing it to read sensor data and transmit the information when required.
In this first phase of the project the team have demonstrated a single-chip 24 GHz / 60 GHz passive radio fabricated in 65 nm CMOS. This chip is fully self-sufficient with no pads or any external components (i.e. power supply) and measures just a few millimetres in size. It integrates RX and TX antennas and provides a communication range up to 50 cm. A modified M-PPM 60 GHz transmitter (6-bits per slot) is used to communicate data sequences as well as the local timing reference. Pulse signalling allows positional information of the chip to be ascertained using time-of-flight information. The chip operates with a standby recovered power of less than 1.5 µW harvested from the reader.