This is the first in a series of articles about the benefits of adding printed batteries to labels or tags to make them active, or semi-passive.
According to research by the RAIN Alliance more than 44.8 billion RAIN tag integrated circuits (ICs) were shipped in 2023. An increase of 32% over 2022. RAIN devices encompass UHF RFID tags and labels and represent a significant section of the total RFID market – showing that RFID devices overall are now ubiquitous.
RFID labels and tags allow products to be identified wirelessly by responding to Radio Frequency (RF) signals sent from readers or beacons to the label (or tag). Passive RFID labels harvest the RF energy emitted by the reader or beacon and re-emit, or “backscatter” a portion of that energy as an identity data signal. The proportion of re-emitted signal backscattered is typically of the order of a millionth of the transmitted energy, which is why they can only be read at short distances and require highly sensitive and expensive readers. Discriminating individual signals emitted by dozens of nearby passive tags increases the technical demands on, and cost of readers.
Active, or semi-passive RFID labels that include batteries are advantageous for several reasons:
Firstly, they increase the distance at which tags can be reliably read. Passive UHF tags can be read at 9 to 12 metres (30 to 40 feet) in ideal conditions. However, in real-world applications the presence of energy absorbing liquids, reflective metal surfaces and RF signal interference reduces read distances significantly to typically a couple of metres. Active (or semi-passive) tags, on the other hand, amplify the return signal and can be read at much longer distances, even at over a hundred metres. This can significantly reduce the cost of beacon installation requirements, or reader complexity when trying to discriminate multiple labels within the read distance.
Secondly, active and semi-passive labels can record data even when there is no ambient RF power is available, such as during transportation and storage in warehouses without dense RF beacon installations. Active or semi-passive labels can continuously measure and record data from sensors, independent of location, storing the data in memory contained in the RFID chip.
Temperature logging labels are an example of how active or semi-passive labels can improve cold chain logistics visibility and product quality data. Incorporating printed batteries allows labels to monitor temperature continuously offline throughout a logistics journey. When the label is accessed by a reader, the complete time-stamped temperature data is downloaded, providing a continuous end-to-end digital record of cold-chain performance.
This is particularly important when shipping items such as pharmaceuticals that need to be kept at a given temperature to ensure therapeutic efficacy. Zinergy works with clients to develop RFID temperature-logging and other active labels. If you are interested in bringing a low-cost active or semi-passive RFID label to market, please email [email protected] for more information
