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RF-energy Harvested mm-Wave SoC for mm-Wave RFID

The Internet-of-Everything (IoE) envisions a connected world with multibillions of sensors that communicate through the Internet, providing real-time information that guides decisions. IoE is projected to be a
key driver of the global economy with overall market size projected to reach $1.7T by 2020. A key limitation to realizing this vision of a fully-sensed and networked world is the development of the sensors itself. An ideal sensor must be physically tiny, have almost infinite battery life, be able to wirelessly communicate with the networks. All of this must achieve this at costs that are compatible with widespread consumer applications (for example, adding a sensor to every object in a store). However, when sensor dimensions are limited to a few millimeters, useful lifetime is limited by the capacity of miniature batteries. Often, it is not practical or cost effective to replace batteries or even physically access the sensor for recharging. Wireless power transfer is a convenient and robust way of powering/recharging sensors remotely but the acceptable distance between wireless power source and sensor needs to be increased for practical applications.

In this CDADIC project, researchers sought to achieve longer wireless powering range for ultra-miniaturized mm-scale sensors. Such tiny sensors can be potentially low-cost. Their small size, however, limits application of traditional wireless powering optimization techniques. Researchers achieved improved performance by developing a systematic circuit design algorithm that optimizes wireless powering for a given sensor area and/or frequency of operation. They also recently demonstrated how this breakthrough’s novel circuitry improves energy harvester performance when starting from zero stored energy. In all cases, the focus has been on integrated technologies that have proven track records of low-cost manufacturing. Such developments have enabled the digital revolution of the past decades.

Other researchers have also been looking at this challenge - prior work on ultra-miniaturized mm-scale sensor transmitters and receivers have shown “pad-less” operation, i.e., the transmitter, receiver, and energy harvesting circuits are all fabricated in a single, inexpensive, integrated circuit that does not require any subsequent packaging or other components.

This breakthrough approach extends the range of such “pad-less” integrated sensor wireless transmitters and receivers by increasing the range of wireless powering. The work also includes a new way of fabricating a miniature antenna along with the transmitter and receiver on the integrated circuit (IC). The new wireless approach ensures more power from the transmitter is radiated by the antenna compared to current state-of-the-art, which means that less energy is required from the battery to wirelessly send a given amount of information.

The wirelessly-powered sensors targeted in this research can significantly impact tracking objects of interest - they can be used for asset-tracking for miniature objects (for example, individual units in a store) or people tracking (for exampling, elder-monitoring in assisted-living facilities).

Economic Impact:

The IoE represents the next stage in the evolution of society towards realtime data analysis and optimized control. The ways in which everyday technologies and tasks can be impacted by the IoE is only limited by individuals’ imagination. This will translate to new technologies that improve productivity and health in society. Miniaturizing such sensors and making them inexpensive enables both replacement of sensors in current applications as well as open new applications. Therefore, such sensors will form a significant enabler for the >$1T IoE economy. CDADIC researchers are working with Texas Instruments and  Intel towards the next generation of such sensors to enable commercialization. Finally, on-going research is preparing graduate students for careers in industry and research, creating engineers who will drive future innovations.

For more information, contact Arun Natarajan at Oregon State University,, Bio:, 541.737.0606.

PDF icon CDADIC-2016.pdf