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. Author manuscript; available in PMC: 2019 Feb 4.
Published in final edited form as: Sci Transl Med. 2018 Dec 5;10(470):eaau1643. doi: 10.1126/scitranslmed.aau1643

Fig. 1. Millimeter-scale, battery-free, wireless sensors of UVA radiation.

Fig. 1.

(A) Photographic images of a dosimeter for measuring UVA exposure dose in a continuous accumulation mode, bent between the thumb and index finger. The diameter, thickness, and weight of the device are 8 mm, 1.5 mm, and 110 mg, respectively. Images of the other three dosimeters show the front and back of the device. (B) Circuit diagram of the system and its wireless interface to a smartphone. The NFC chip, the MOSFET, the SC, and the photodetector are labeled NFC, MOS, SC, and PD, respectively. GND indicates ground. (C) Schematic, exploded view illustration of the constituent layers: the RF antenna (Cu coil), the NFC chip (NFC), the passive components, the UVA photodetector (PD), the SC (SC), and the insulating film (PI). (D to I) Photographic images demonstrating the flexibility of the sensor on various body parts, materials, and form factors. Insets in (F) and (I) show higher-magnification images.