An UHF Passive RFID Transponder Using A Low-Power Clock Generator without Passive Components

In this work, we propose a Radio Frequency IDentification (RFID) transponder operating in the UHF range. The RFID transponder encompasses the RF front-end circuit and signal processing unit. Of which, the RF front-end circuit consists of the voltage multiplier, voltage regulator, bias circuit, Power On Reset (POR), clock generator and ASK modulator/demodulator. This work proposes a ring oscillation scheme for the clock generator in the RF front-end circuit, which is capable of generating the two clock signals it requires without the use of the capacitor, resistor and inductor. Such scheme not only reduces the area it may require for the three kinds of passive components, it also reduces the power consumption. By using the TSMC 0.35-μm CMOS technology, the proposed RFID transponder with an area of 0.31 mm² is implemented based on the ISO 18000-6 standard where the clock generator consumes only 0.4 μW.