New technology makes passive RFID tags up to 25 percent smaller

Researchers at North Carolina State University in the United States have managed to make passive RFID tags up to 25 percent smaller because AC voltage no longer has to be converted into DC voltage first.

This means that the necessary hardware, a rectifier and capacitors, is no longer needed, which ensures the smaller chips. To achieve this, the researchers used a so-called rf-only circuit, which should make the chip smaller and cheaper in the long run.

Passive RFID tags without their own energy supply, such as a battery, use the electromagnetic field of an RFID reader to generate energy via a coil. This means that in practice a passive tag can only be read at a short distance. These kinds of tags can be found in many everyday objects, such as passes to open gates, but also for tracking goods in warehouses.

The research team managed to shrink an rfid tag and directly drive it through alternating current by adding certain transistors to the chip’s circuitry. The so-called ‘RF-only logic’ RFID tags cannot yet bridge the same distance as the current passive tags, but the team believes that this can be solved in the future.

The chip developed is compatible with UHF EPC Gen 2 standard. The rfid tag is made with 0.13 micrometer cmos technology and measures 0.6 by 0.3 millimeters.

The research was presented at the IEEE’s annual RFID conference.