We are surrounded by Bluetooth radio signals and most of the devices that we see around — smartphones, wireless computer networks, and wireless earbuds — use Bluetooth transmitters for transmitting signals. However, contemporary transmitters have two problems: heavy power consumption which is why Bluetooth earbuds usually have a talk time of just 4 to 5 hours, and the second issue is the size of the antenna.
Now, engineers from the University of Michigan have invented the world’s first-millimeter sized device that can transmit Bluetooth signals and runs on less than 1-milliwatt. The transmitter chip was presented to the world at the IEEE International Solid State Circuits Conference last month.
This new transmitter consumes just 0.6 milliwatts for transmitting signals and can be powered by a commonly used 5.8mm coin battery. It can broadcast signals for 11 years using a coin battery.
Currently-used transmitter circuits consist of a tunable RF oscillator for generating the frequency, an amplifier for boosting amplitude and an antenna to emit the signals.
Speaking to IEEE Spectrum, David Wentzloff, an associate professor involved in the research, said that the device solves the two issues prevalent in contemporary transmitters. The engineers invented a ‘power oscillator’ by combining the oscillator and antenna that does not require an amplifier.
They also built an on-chip transformer into the circuit that supplied power to the power oscillator — thus making the transmitter more compact.
How Would This Invention Help?
Wentzloff said, “If you wanted to make a millimeter-scale tracker device, this is all you’d need.”
The next step, according to Wentzloff, is adding this BLE radio to the millimeter scale sensors that are developed under the University of Michigan’s M3 project. The energy efficient, tiny BLE transmitter would also help in developing small-sized IoT devices.