A Linearization Technique for RF Receiver Front-End Using Second-Order-Intermodulation Injection

A linearization technique is proposed in which low-frequency second-order-intermodulation (IM₂) is generated and injected to suppress the third-order intermodulation (IM₃). The proposed linearization technique is applied to both a low-noise amplifier (LNA) and a down-conversion mixer in an RF receiver front-end (RFE) working at 900 MHz. Fabricated in a 0.18 mum CMOS process and operated at 1.5 V supply with a total current of 13.1 mA, the RFE delivers 22 dB gain with 5.3 dB noise figure (NF). The linearization technique achieves around 20 dB IM₃ suppression and improves the RFE's IIP₃ from -10.4 dBm to 0.2 dBm without gain reduction and noise penalty while requiring only an extra current of 0.1 mA.