The high frequency range includes frequencies from 3 to 30 MHz but only one
frequency, 13.56 MHz, is used for RFID applications. This frequency is now
available for RFID applications worldwide with the same power level. Tags and
interrogators using 13.56MHzare generally called the HF tags and the HF interrogators.
They, like the LF tags, also use near-field inductive coupling to obtain
power and to communicate with the interrogator. HF tags are passive tags and
have short read range, less than 3 feet. They have a lower data transfer rate than
the UHF frequencies but a higher data rate than the LF. The HF tags may have
anti-collision capability that facilitates reading of multiple tags simultaneously
in the IZ. Since the read range of many HF tags and interrogators is small, they
usually do not implement anti-collision. This reduces the complexity and cost.