I would like to monitor the insects from approximately 2 inches away, or slightly less, using radio frequency identification. Each insect measures approximately 0.5 inch in size. I do not require long-range tracking. What are my options?
—Name withheld
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There have been examples of researchers using RFID to track insects. For example, an international group of scientists employed tiny passive high-frequency (HF) RFID tags to track how long it takes foraging honeybees to return to their hive from a variety of release locations (see RFID Helps Scientists Study Honeybees’ Homing Behavior).
This solution worked because the researchers were monitoring only when the bees left the hive and returned—the tags were read in proximity to the hive. Tracking insects as they move within a space is more challenging, since passive RFID systems can tell you only that an object is within a general area; they cannot pinpoint a moving insect.
One option might be to utilize an ultrahigh-frequency (UHF) transponder with an on-chip antenna. Malaysian chip manufacturer FEC International has created a tag antenna designed to fit onto an EPC Gen 2 UHF RFID chip, thereby resulting in a fully functioning EPC RFID tag about the size of a grain of sand.
The FEC antenna has been mounted on NXP Semiconductors‘ Ucode G2XM chip, which measures just 0.46 millimeter by 0.48 millimeter (0.018 inch by 0.019 inch). The tags have a 1-millimeter (0.04-inch) read range (see Chip-size EPC Gen 2 Tag Promises to Enable New Applications). So the only way to track an insect’s movement over a large area would be to place many small antennas in a grid pattern under the floor, and then record movements from one square to the next.
—Mark Roberti, Founder and Editor, RFID Journal