Fig 2. Wireless wearable sensor W²ISP and hospital room configuration.

(a) Hospital patient wearing a W²ISP sensor (≈ 3 g, dimensions: 18 × 20 × 2 mm), flexible antenna (36 × 85 × 2 mm) and isolating silver fabric (230 × 220 mm) on top of a gown for illustrative purposes; also shown are the axes of the accelerometer embedded in the W²ISP. (b) Layout of furniture and equipment with antennas shown in circles; antenna2 and antenna3 are at ceiling level on top of bed and antenna1 inclined towards the chair.