You may be asking yourself, “so what exactly makes up an RFID label?”
In this post, I’ll break down the components of an RFID label (or tag).
An RFID tag consists of three main components: the substrate, the RFID chip, and an antenna.
The substrate is the housing for the chip and antenna. Depending on the tag’s environment, the housing can range from paper to heavy duty plastic. Some sample RFID labels can be seen below:
The RFID Chip, also known as an integrated circuit or IC, is a microprocessor and stores data in memory banks. Memory banks are where the tag stores information. Most tags have banks that are made to be used once. However, some tags have banks that can have their data replaced which makes them reusable.
The RFID chip functions in two primary methods: active and passive. Active tags require a power source like a battery and are usually used in container and pallet tracking, asset tracking, and personnel tracking where detection needs to be hundreds of feet. They are considered “active” since they are always transmitting information.
Passive tags do not require a power source and use the energy from an RFID reader’s signal to activate and send its information. These tags are the most cost effective and are used in a wide variety of industries.
In the cannabis market, the METRC plant and package tags are passive, write-only one time tags so that a RFID label is used only one time and cannot be associated with another plant or package. This ensures supply-chain transparency and eliminates the need to reprogram tags.
The antenna is the largest part of the tag and is connected to the tag IC. The antenna receives the signals from the interrogator and, depending on tag type, it either transmits or reflects the received signal back. For active tags, it transmits the signals, and for semi-passive and passive tags, it reflects the signals. For passive tags, the antenna also collects power from the radio waves and supplies it to the IC.
The geometry and design of the antenna is particularly important depending on the use case for RFID. You will hear terms such as “single coil”, “dipole”, and “dual dipole” when discussing antenna design. The design of the tag antenna affects tag readability in different environments.
For example, Yobi created a custom RFID tag for use with the mylar bags that are widely used to package and sell cannabis. Since mylar bags include enough metal to disrupt RFID tag transmission, our label design includes an antenna component that is positioned off of the mylar so RFID antennas can still quickly read hundreds of items in a minute.
When working with RFID, it’s important to remember to use the “right tool for the right job”. RFID can save cannabis operations thousands of dollars when applied correctly. If you have questions about how RFID can improve your operations, let us know!