Battery-less Transmitter and Frequency-Agile Receiver for IoT Applications

[摘要] Recent increasing demands for IoT device, wearable device and biomedical implants have been calling for more low power, energy efficient and highly integrated devices from electronic industry.Implementing transmitter and energy-harvesting circuits on a same chip is a good way to provide battery-less systems for data transmission in wireless sensor networks. Prior wireless powered devices work used sub-gigahertz microwaves and require very large antenna for energy harvesting, which prevents their application in biomedical implants and single-chip integration. Our work on battery-less transmitter integrated on-chip antenna for 8 to 10 GHz wireless energy harvesting. This approach reduced antenna size and provided stable 10uW energy source for duty-cycled operating transmitter. The transmitter used On-Off Key (OOK) modulation. Oscillator, a class-E power amplifier and a dipole on-chip antenna are the main components of the transmitter. The transmitter operates at 1.46GHz and consumes 25mW power. The on-chip antenna is matched to the transmitter at 1.46GHz and could radiate up to -20dBm power into the air. By modulating from an external signal source, the data rate can be as high as 50M Bit/sec. The transmitter is able to harvest power from a radiating antenna 30cm away from the chip with a size of 7.4mm2 and transmit data back. Thus it is suitable for biomedical implant and wearable devices. On the other hand, our work introduced a frequency-agile receiver that detect and switch to the most power efficient channel quickly. The receiver consists of a band-switching low noise amplifier (LNA), an all-digital-phase-locked-loop (ADPLL), a power detector and a successive approximation analog to digital converter. The receiver worked at 4.3 to 5.7GHz and provide quick band-switching on the LNA and ADPLL.It provides quick and accurate channel selection in quickly changing environments.

[发布机构] Rice University

[效力级别] Harvesting