A switchable dual-mode fully-differential common-source low-noise amplifier in 0.18-μm CMOS technology

A highly-integrated switchable dual-mode low-noise amplifier (LNA) is proposed and implemented in standard 0.18 μm complementary metal-oxide-semiconductor (CMOS) technology for ultra-high frequency-radio-frequency identification (UHF RFID) reader receivers. This dual-mode LNA can be controlled to operate in two different modes in order to meet the requirements for the listen-before-talk mode and the normal mode of the UHF RFID reader receiver, respectively. The fully-differential common-source cascode topology with perfect input impedance matching, capacitive cross-coupling, and common-mode feedback techniques are employed to improve its performance. Measurement results show that, from a single power supply of 1.8 V, the LNA achieved the power gain (S21) of 9.1 dB, the input power reflection (S11) of −20 dB, the minimum noise figure (NF) of 3.6 dB, and the P_1dB of −5 dBm in high-gain mode. In high-linearity mode, S21 of 3.2 dB, S11 of −17 dB, NF of 5.2 dB, and P1dB of −1.3 dBm were obtained.