This work presents the design, fabrication, and characterization of a passive printed radiofrequency identification tag in the ultra-high-frequency band with multiple optical sensing capabilities.This tag English Reins includes five photodiodes to cover a wide spectral range from near-infrared to visible and ultraviolet spectral regions.The tag antenna and circuit connections have been screen-printed on a flexible polymeric substrate.An ultra-low-power microcontroller-based switch has been included to measure the five magnitudes issuing from the optical sensors, providing a spectral fingerprint of the incident electromagnetic radiation from ultraviolet to infrared, without requiring energy from a battery.
The normalization procedure has been designed applying illuminants, and the entire system was tested by measuring cards from a colour chart and sensing CHOLESTEROL CONTROL fruit ripening.