Designing a DIY RFID Tag Antenna

We cover a lot of projects here on the Hackster blog that integrate NFC (near-field communication) or RFID (radio-frequency identification) tags. RFID, and its NFC subset, works when the radio waves emitted by the reader energize the chip’s antenna. Once the chip has power, it can return a signal with a small amount of data. But, we tend to overlook the importance of the antenna itself. It turns out that the antenna is very complicated in it’s own right, as demonstrated in this Strange Parts YouTube video.

Scotty of Strange Parts was challenged by his friend Stuart to make his own RFID tag after dissecting a commercial tag from a cashier-free store in Yiwu, China. He figured it couldn’t be that hard — after all, an antenna is just a bit of metal, right? Of course, we’re writing an article about it, so it obviously turned out to be quite the challenge.

The first antenna design Scotty tried was made from simple hand-cut aluminum foil. Attaching the chip to the antenna required some unconventional soldering iron tips and a microscope to position it. That initial design worked in close range, and it turns out that even a loop of copper wire will work if the tag is basically touching the reader. But, those designs didn’t work over longer ranges. To crack that nut, Scotty flew to Seattle to visit Impinj, which is a company that specializes in RFID tags. There, he learned how real RFID antennas are designed, and it turns out you can make your own with a standard craft cutting machine!