Wireless-power transmitter with distance sensor for ultra-small wearable devices

Nishihashi, Takeshi; Nishikawa, Hisashi; Kashiyama, Norifumi; Tanaka, Ami; Douseki, Takakuni

doi:10.1109/icsens.2017.8234199

Cited by 5 publications

(1 citation statement)

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“…We previously developed a power-controlled 2.45-GHz wireless power transmitter with a distance sensor that measures the distance from the transmitter to the human body. [1] Using the measured distance, the transmitter emits controlled electromagnetic waves with an electric field strength below that of Japan's national guidelines [2] while maintaining a constant power supply to the target device even if the distance between the human body and the transmitter changes. We also developed an intermittent power transfer system [3][4][5] that increases the distance from the transmitter to the wearable device while maintaining the average transmitted power.…”

Section: Introductionmentioning

confidence: 99%

Slidable Button-shaped Rectifier Module with LED on Conductive Yarn for Antenna Matching Powered by Microwaves

Nishimura

Tanaka

Otsuka

et al. 2022

Transactions of The Japan Institute of Electronics Packaging

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This paper describes a gamma-matched textile rectenna structure that is suitable for batteryless wearable accessories powered by microwaves using a conductive-yarn antenna. The proposed structure consists of a slidable button-shaped rectifier module with LED that allows the antenna to pass through its metal holes, thus making it possible to connect a soft textile antenna with a hard rectifier module to easily perform impedance matching by sliding the module on the antenna, while watching luminance of the LED light. To verify the effectiveness of our textile rectenna structure, we fabricated a button-shaped rectifier module 7.5 mm in diameter including an LED and a 6-cm-long bundled conductiveyarn antenna consisting of 0.5-mm-thick single yarns. The experimental results showed that, for 2.45-GHz wireless power transmission with an average transmitted power of 1 W, the LED on the rectifier module blinked while dissipating power of 0.355 mW at a distance of 70 cm from the wireless transmitter. We also fabricated a friendship bracelet and a pair of embroidered socks equipped with our rectenna as LED textile accessories.

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Section: Introductionmentioning

confidence: 99%