title: On-body calibration and measurements using a personal, distributed exposimeter for wireless fidelity.
abstract: This paper describes the design, calibration, and measurements with a personal, distributed exposimeter (PDE) for the on-body detection of radio frequency (RF) electromagnetic fields due to Wireless Fidelity (WiFi) networks. Numerical simulations show that using a combination of two RF nodes placed on the front and back of the body reduces the 50% prediction interval (PI50) on the incident free-space electric-field strength (Equation is included in full-text article.). Median reductions of 10 dB and 9.1 dB are obtained compared to the PI50 of a single antenna placed on the body using a weighted arithmetic and geometric average, respectively. Therefore, a simple PDE topology based on two nodes, which are deployed on opposite sides of the human torso, is applied for calibration and measurements. The PDE is constructed using flexible, dual-polarized textile antennas and wearable electronics, which communicate wirelessly with a Universal Serial Bus (USB) connected receiver and can be unobtrusively integrated into a garment. The calibration of the PDE in an anechoic chamber proves that the PI50 of the measured (Equation is included in full-text article.)is reduced to 3.2 dB. To demonstrate the real-life usability of the wireless device, a subject was equipped with the PDE during a walk in the city of Ghent, Belgium. Using a sample frequency of 2 Hz, an average incident power density of 59 nW m was registered in the WiFi frequency band during this walk.
authors.affiliation: *Wireless & Cable Group, Department of Information Technology, Ghent University/iMinds Gaston Crommenlaan 8, B-9050 Ghent, Belgium; †Electromagnetics Group, Department of Information Technology, Ghent University Sint-Pietersnieuwstraat 41, B-9000 Ghent, Belgium; ‡Micro-electronics and Sensors, ESAT-MICAS, KULeuven, Kasteelpark Arenberg 10-bus 2443, B-3001 Leuven, Belgium.
authors.forename: Arno
authors.initials: A
authors.lastname: Thielens
authors.forename: Sam
authors.initials: S
authors.lastname: Agneessens
authors.forename: Hans
authors.initials: H
authors.lastname: De Clercq
authors.forename: Jeroen
authors.initials: J
authors.lastname: Lecoutere
authors.forename: Leen
authors.initials: L
authors.lastname: Verloock
authors.forename: Emmeric
authors.initials: E
authors.lastname: Tanghe
authors.forename: Sam
authors.initials: S
authors.lastname: Aerts
authors.forename: Robert
authors.initials: R
authors.lastname: Puers
authors.forename: Hendrik
authors.initials: H
authors.lastname: Rogier
authors.forename: Luc
authors.initials: L
authors.lastname: Martens
authors.forename: Wout
authors.initials: W
authors.lastname: Joseph
mesh_terms: D001530:Belgium; D002138:Calibration; D003198:Computer Simulation; D004574:Electromagnetic Fields; D004781:Environmental Exposure; D006801:Humans; D019047:Phantoms, Imaging; D011834:Radiation Monitoring / Q000295:instrumentation*; D059015:Wireless Technology