Antenna-Impregnated Fabrics for Recumbent Height Measurement on the Go

A novel class of antenna-impregnated fabrics is proposed for wireless and unobtrusive height measurement on the go. Contrary to conventional infantometer and stadiometer technologies that restrict height monitoring to sporadic intervals, this technology brings forward regular height monitoring with minimum impact to the individual's activity. The proposed fabrics consist of multiple dipole antennas placed at known distances from each other. When a subject lies upon the fabric, he/she detunes the underlying antennas, inducing losses in the associated wireless transmission paths. Therefore, the subject's height can be calculated by identifying the two antennas with degraded transmission coefficients at the starting (head) and ending (feet) points. For validation, a proof-of-concept 52 cm × 43 cm fabric operating at 915 MHz is designed, fabricated, and tested. Simulation and in vitro measurement results demonstrate the feasibility of retrieving the length of a 16-cm-long phantom, regardless of its exact location upon the fabric. Concurrently, the proposed fabric is shown to conform to the Federal Communication Commission guidelines for the Specific Absorption Rate (SAR). This technology can eventually be integrated into baby cribs, bed sheets, or rollable mats to provide early detection/monitoring of Turner syndrome, Crohn's disease, short stature, Celiac disease, growth hormone deficiency, and obesity, among others.