Auditing of ultra dense RFID straws in cryogenic container at -196°C

This paper presents a new auditing system scheme based on radio frequency identification technologies for cryopreservation applications using liquid nitrogen at temperature of -196°C. Conventional approaches such as hand written labels or printed barcodes suffer from the significant manual labor work and freeze-thaw-damaging risk of the sample. The proposed scheme integrates miniaturized RFID electronic devices and antennas in the thin cryogenic straws without significantly changing their dimensions. In addition, 900 MHz frequency band is chosen for long reading range, which eliminates the need to take the preserved biological samples out of liquid nitrogen and minimizes the damaging risk. Four most important technical aspects for the system have been identified and investigated: 1. The link budget is evaluated by FDTD numerical simulations to make sure the RF signal strength meets the requirement for the reading range. 2. The total efficiency of small and tightly coupled RFID dipole antennas is studied and obtained by simulations. 3. The current-voltage behaviors of two types of transistors in typical RFID electronics have been characterized by measurements to identify the suitable transistor type for reliable circuit designs at -196°C. 4. The easy-to-access and anti-collision reading system for fast data collection is analyzed. The obtained results indicate that the proposed scheme is feasible, which can be beneficial for the relevant scientific fields.