Realizes Data Transmission with Only Tiny Power Collected from Ambient Radio Waves

June 14, 2011

TOKYO, Japan, June 14, 2011 — Renesas Electronics Corporation (TSE: 6723), a premier provider of advanced semiconductor solutions, today announced the development of a new near field (range of less than one meter) wireless technology that enables transmission by an ultra-compact terminal (sensor node) of a variety of types of sensor information to mobile devices utilizing widely used wireless communication standards such as Bluetooth (Note 1) and wireless LAN, using only a tiny amount of power.

While the data transmission via Bluetooth or wireless LAN typically requires a sensor node transmitter that consumes more than 10 milliwatts (mW) of power, the new near field wireless technology uses only several microwatts (µW), approximately a magnitude of 1,000 less. This enables data transmission via the tiny amount of power collected from ambient radio waves (Note 2), realizing battery-less sensor nodes.

Recently, advances in the fields of information and communication have changed from innovations that enable people to intentionally transmit information to innovations that enable objects themselves to transmit information in anticipation of the consciousness and actions of people. Examples include digital signage, which conveys promotional information in real time to people nearby, and health monitoring systems that enable people to track the state of their health. Many new services of this sort, which involve objects transmitting information, are expected to appear and become widespread in the years ahead. Advances in sensor node technology will play a key role in allowing these new services to expand.

Using commonly available wireless equipment, such as Bluetooth or wireless LAN devices, data transmitted by a sensor node, such as physical information on temperature, humidity, or stress; personal (ID) information; or statistical information, needs to be read through a Bluetooth or wireless LAN transmitter, which are incorporated into the sensor node, and this results in the sensor node consuming a peak power consumption of as much as several tens of mW. The sensor node therefore requires a battery, and as a result the sensor node has to go through the periodic maintenance necessary for battery replacement, and also the overall size of the sensor node is increased. The size and need for maintenance impose limitations on the locations where the sensor node can be installed.

To provide a solution that overcomes these bottlenecks, Renesas has developed a new sensor node technology that enables battery-less operation while making it possible to build a system composed of commonly used wireless communication devices (Note 3).

The newly developed technology includes; (1) Sensor node technology that enables the receivers of widely-used wireless communication equipment, such as Bluetooth or wireless LAN devices, to read sensor information by altering the signal to noise (S/N) ratio of radio waves travelling between the transmitters and receivers; and (2) Energy harvesting technology (Note 4) that converts the energy in ambient radio waves into electrical energy.

Using an evaluation board mounted with a performance-evaluation chip and antenna, we have confirmed physical information such as temperature and humidity can be transmitted using only a few µW of power using the new technology. The newly developed technology makes it possible to use a mobile device such as smartphones equipped with Bluetooth or wireless LAN functionality to receive information from a sensor node around a range of less than one meter. In addition, the new technology also enables data transmission using very low power, on the order of several µW. This makes it possible to build battery-less sensor nodes that collect energy from ambient radio waves by using energy harvesting technology.

Applications for the newly developed sensor node technology include, for example, a battery-less electronic calculator that would allow copying and pasting of calculation results to a notebook PC simply by bringing it into near proximity with the PC, or compact and handy adhesive plasters or bandages with built-in temperature sensors that could monitor body temperature.

Renesas considers that the new technology will serve as a foundation for the realization of innovation related to “objects that transmit information” in the years ahead, and for more efficient “device control” that will help in the building of an eco-friendly, green “smart city”. Renesas plans to accelerate its R&D work moving forward.

Renesas will announce the results of its development work on June 16 at the 2011 Symposium on VLSI Circuits, to be held in Kyoto from June 15 to 17.

(Note 1) Bluetooth: A short-range wireless communication technology for linking devices such as mobile information devices. It is widely used to provide wireless connections between personal computers and peripherals such as mouses and keyboards.

(Note 2) Ambient radio waves: Radio waves in the environment around us from sources such as Bluetooth devices, wireless LANs, and mobile phones.

(Note 3) If there were a person at the opposite shore and the other person needed to transmit data to that person, switching on and off a flashlight can be described as utilizing the existing technology, while reflecting sunlight off a mirror can be described as utilizing the newly developed technology. Although data transmission using a flashlight would require the flashlight to consume large amount of energy, a mirror would only require a tiny amount to realize data transmission by simply turning the mirror. For the newly developed technology, turning the mirror is equivalent to the role of sensor nodes and the person at the opposite shore can be considered as the mobile handset. If wireless LAN were used, the sun can be considered as a wireless access point.

(Note 4) Energy Harvesting Technology: Environmentally friendly power generating technology that converts energy from sources in the world around us, such as heat, vibrations, and radio waves, into electrical energy.

About Renesas Electronics Corporation

Renesas Electronics Corporation (TSE: 6723) delivers trusted embedded design innovation with complete semiconductor solutions that enable billions of connected, intelligent devices to enhance the way people work and live. A global leader in microcontrollers, analog, power and SoC products, Renesas provides comprehensive solutions for a broad range of automotive, industrial, infrastructure, and IoT applications that help shape a limitless future. Learn more at Follow us on LinkedIn, Facebook, Twitter, and YouTube.

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