What communication method enables low-power, passive reading of a small tag or patch on an object located anywhere from a few feet to dozens of feet away?

RFID can be used to identify and read a "passive" (no power) tag, which is essentially an antenna, when it passes within a few feet of the reader. RFID tags are commonly used in business and retail to track inventories. The distance for RFID implementation is determined by the antenna's size and polarization, as well as the frequency and power employed, among other factors. NFC requires only a few centimeters of area. Wi-Fi is an 802.11-based wireless networking standard. Radio frequency interference (RFI) is a nuisance that has the potential to impair network connections.