Abstract: A radio frequency identification tag includes an antenna terminal, a memory, a D/A converter, a clock extractor, a frequency synthesizer, a radio frequency UP converter, and a power unit. An energy pumping signal is received and tag identification information is transmitted through the antenna terminal. The tag identification information is stored in the memory. The D/A converter converts the tag identification information into an analog signal in response to an information request signal included in the energy pumping signal. The clock extractor extracts a clock signal from the energy pumping signal. The frequency synthesizer is operated according to the clock signal of the clock extractor, and generates a frequency. The radio frequency up converter up-converts a signal output from the D/A converter, and allows the up-converted signal to be transmitted through the antenna terminal. The power unit supplies internal power.