Room-scale wireless power transfer via multimode quasistatic cavity resonance

This work presents an technology termed multimode quasistatic cavity resonance for enabling efficient and safe wireless power throughout a room-scale volume. The approach generates multiple three-dimensional magnetic field patterns, and achieves a power delivery efficiency exceeding 37.1% throughout a 3 m × 3 m × 2 m test room. With this approach, power exceeding 50 W could potentially be delivered to mobile receivers in accordance with safety guidelines.

Related publications

1. Takuya Sasatani, Alanson P. Sample, Yoshihiro Kawahara, "Room-scale magnetoquasistatic wireless power transfer using a cavity-based multimode resonator," Nature Electronics, 2021.

2. Takuya Sasatani, Matthew J. Chabalko, Yoshihiro Kawahara, and Alanson P. Sample, “Multimode Quasistatic Cavity Resonators for Wireless Power Transfer,” IEEE Antennas and Wireless Propagation Letters, 2017. [paper]

3. 笹谷拓也，川原圭博，“部屋全域への無線電力伝送に向けたマルチモード準静空洞共振器,” 研究報告ユビキタスコンピューティングシステム（UBI）, 2019. 山下記念論文賞 & 優秀論文賞

Alvus: an instantly reconfigurable 2-D wireless power transfer system

We often place devices on surfaces such as desks and shelves; thus, deploying 2-D wireless power transfer on these surfaces can offer a ubiquitous charging experience. This work presents a reconfigurable 2-D wireless charging system, leveraging the "multi-hop" power transfer effect for facilitating the deployment of such functional surfaces.

Related publications

1. Kazunobu Sumiya, Takuya Sasatani, Yuki Nishizawa, Kenji Tsushio, Yoshiaki Narusue, and Yoshihiro Kawahara, “Alvus: A Reconfigurable 2-D Wireless Charging System,” ACM IMWUT, 2019. [paper] Distinguished paper award (formerly the best paper award)

A cuttable wireless power transfer sheet

To integrate wireless power transfer (WPT) functions into daily surfaces, people need to design a coil array according to the size and shape of the target surface. This work presents a cuttable WPT sheet that only requires users to cut and paste a ready-made sheet to augment everyday surfaces into a wireless charging surface.

Related publications

1. Ryo Takahashi, Takuya Sasatani, Fuminori Okuya, Yoshiaki Narusue, and Yoshihiro Kawahara, “A Cuttable Wireless Power Transfer Sheet,” ACM IMWUT, 2018. [paper]

Room-wide wireless power transfer and low-power communication for the Internet of Things

To achieve long-term operation of IoT systems, ubiquitous wireless power transfer, and low-power communication systems are necessary. This work presents a wireless power/data transfer system, which co-exists on the 3-D magnetic field channel generated by a room-scale quasistatic cavity resonator.

Related publications

1. Takuya Sasatani, Chouchang Jack Yang, Matthew J. Chabalko, Yoshihiro Kawahara, and Alanson P. Sample, “Room-Wide Wireless Charging and Load-Modulation Communication via Quasistatic Cavity Resonance,” ACM IMWUT, 2018. [paper]

TelemetRing: a batteryless and wireless ring-shaped keyboard using inductive telemetry

TelemetRing is a batteryless and wireless ring-shaped keyboard that supports command and text entry in daily lives by detecting finger typing on various surfaces. The proposed inductive telemetry approach eliminates bulky batteries or capacitors from the ring part.

Related publications

1. Ryo Takahashi, Masaaki Fukumoto, Changyo Han, Takuya Sasatani, Yoshiaki Narusue, and Yoshihiro Kawahara, “TelemetRing: A Batteryless and Wireless Ring-shaped Keyboard using Passive Inductive Telemetry,” ACM UIST, 2020.

Twin Meander Coil: Sensitive Readout of Battery-free On-body Wireless Sensors

Energy-efficient wearable sensing platforms are essential for ubiquitous healthcare applications. This paper presents Twin Meander Coil for wirelessly connecting battery-free on-body sensor tags. We built a prototype with a industrial knitting machine and showed that the system can collect information such as ID, touch, rotation, and pressure via the tag's frequency response.

Related publications

1. Ryo Takahashi, Wakako Yukita, Takuya Sasatani, Tomoyuki Yokota, Takao Someya, and Yoshihiro Kawahara, “Twin Meander Coil: Sensitive Readout of Battery-free On-body Wireless Sensors using Body-scale Meander Coils,” ACM IMWUT, 2021.

Empowering robots with circuit/wireless technology

As robots become more complex, small, and sophisticated, the cost and effort necessary for “wiring” become critical. This series of work explore techniques for efficiently empowering the system peripherals necessary in robotic applications.

Related publications

1. Colm McCaffrey, Takuya Umedachi, Weiwei Jiang, Takuya Sasatani, Yoshiaki Narusue, Ryuma Niiyama, Yoshihiro Kawahara, “Continuum robotic caterpillar with wirelessly powered shape memory alloy actuators”, SoftRobotics, 2020.

2. Yuki Nishizawa, Takuya Sasatani, Matthew Ishige, Yoshiaki Narusue, Takuya Umedachi, Yoshihiro Kawahara, “Ramus: A Frequency-Multiplexed Power Bus for Powering, Sensing and Controlling Robots,” IEEE Robotics and Automation Letters, 2020.

3. Lai Chen, Takuya Sasatani, Keung Or, Satoshi Nishikawa, Yoshihiro Kawahara, Ryuma Niiyama, and Yasuo Kuniyoshi, "Wireless powered dielectric elastomer actuator," IEEE Robotics and Automation Letters (Proc. IROS), 2021.

Wirelessly Cooperated Shape-Changing Computing Particles

A critical challenge for achieving computational materials is to weave computers into everyday objects consisting of various shapes and form factors. One route towards this vision is to build physical computational particles that can cooperatively communicate among others and change the whole shape like clay. Wireless communication and powering are keys to embodying such computing particles. We introduce an approach to interface these particles using multiple tiny IC chips, which wirelessly cooperate with each other.

Related publications

1. Junichiro Kadomoto, Takuya Sasatani, Koya Narumi, Naoto Usami, Hidetsugu Irie, Shuichi Sakai, Yoshihiro Kawahara, “Toward Wirelessly Cooperated Shape-Changing Computing Particles,” IEEE Pervasive Computing 2021.

Designing wireless power receivers with Genetic Algorithm

Related publications

1. Takuya Sasatani, Yoshiaki Narusue, and Yoshihiro Kawahara, “Genetic Algorithm-Based Receiving Resonator Array Design for Wireless Power Transfer,” IEEE Access, 2020.

Silver Tape: inkjet-printed circuits peeled-and-transferred on versatile substrates

Related publications

1. Tingyu Cheng*, Koya Narumi*, Youngwook Do, Yang Zhang, Tung D. Ta, Takuya Sasatani, Eric Markvicka, Yoshihiro Kawahara, Lining Yao, Gregory D. Abowd, and HyunJoo Oh, “Silver Tape: Inkjet-Printed Circuits Peeled-and-Transferred on Versatile Substrates,” ACM IMWUT, 2020.

Wireless power transfer and communication over the hinges of smart glasses

Related publications

1. Ken Takaki, Takuya Sasatani, Hironobu Kasashima, Yoshihiro Kawahara, and Takeshi Naemura “Coil Design for Wireless Power Transfer and Communication over Hinges of Smart Glasses,” ISWC, 2020.

Inkjet printed, passive, and contactless epidermal pressure sensor

Related publications

1. Takahiro Hashizume, Takuya Sasatani, Koya Narumi, Yoshiaki Narusue, Yoshihiro Kawahara, and Tohru Asami, “Passive and Contactless Epidermal Pressure Sensor Printed with Silver Nano-particle Ink,” ACM UbiComp, 2016.

2. 橋爪崇弘，笹谷拓也，成末義哲，川原圭博，浅見徹，”銀ナノインクを用いた非接触読み取り可能なパッシブ型静電容量式圧力センサと着圧測定への応用，” DICOMO2016. 最優秀論文賞 & 優秀プレゼンテーション賞

Dynamic complex impedance conversion using multiple-input DC/DC converters

Related publications

1. Takuya Sasatani, Yoshiaki Narusue, and Yoshihiro Kawahara, “Dynamic Complex Impedance Tuning Method Using a Multiple-Input DC/DC Converter for Wireless Power Transfer,” IEEE WPTC 2018. Best Student Paper Finalist

Wireless power transfer for personal mobility devices

Related publications

1. Hiromasa Hayashi, Katsuhiro Hata, Takuya Sasatani, Hiroki Sato, Ryosuke Yamamura, Young ah Seong, Ryuma Niiyama, and Yoshihiro Kawahara, “Effect of Body Materials on Transmission Efficiency and Resonant Frequency in Wirelessly Powered Personal Mobility Devices,” IEEE WPTC 2020.

2. Hiromasa Hayashi, Takuya Sasatani, Yoshiaki Narusue, and Yoshihiro Kawahara, “Design of Wireless Power Transfer Systems for Personal Mobility Devices in City Space,” IEEE VTC 2019.