An improved 860-960Â MHz fully integrated CMOS power amplifier designation for UHF RFID transmitter

An improved design of 860-960 MHz fully integrated CMOS power amplifier (PA) for UHF RFID transmitter is presented in this paper. It utilizes three stage differential structure, including common-source structure applying RC feedback circuit to improve linearity, cascade structure adopting self-biased cascode technique and self-forward-body-bias (SFBB) technique to overcome shortcomings of low breakdown voltage and to reduce supply voltage respectively in order to obtain high output power, high efficiency and low supply voltage. By integrating these techniques organically, simulation results demonstrate that the circuit provides 21 dBm output power and 35% power-added efficiency (PAE) with 3 V supply. A comparison with other PAs operating in similar frequencies shows the proposed LNA has advantages of higher output power, higher PAE, higher linearity and lower supply voltage.