Wireless Battery-Free Sensor Probe for Temperature/Humidity Measurement in Sustainable Pharmaceutical Blister

The transition toward fully recyclable full-plastic blister packs in the pharmaceutical industry is driven by sustainability objectives. However, the variable permeability of these materials to humidity and temperature fluctuations can compromise drug stability, posing challenges in selecting optimal packaging materials, defining fabrication and assembly procedures, and detecting potential micro-leaks. This paper presents a miniaturized passive UHF RFID sensor probe designed for direct in-cavity monitoring of temperature and relative humidity in full-plastic blister packs. The proposed sensor, with a circular form factor measuring 10 mm in diameter and 2 mm in thickness, is specifically designed for seamless integration within a blister cavity. A first prototype of the sensor tag was fabricated and experimentally validated, demonstrating a theoretical maximum reading distance of up to 60 cm in passive mode.