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

Abstract

A linearization technique is proposed in which low-frequency second-order-intermodulation (IM 2 ) is generated and injected to suppress the third-order intermodulation (IM 3 ). 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 m 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 IM 3 suppression and improves the RFE's IIP 3 from 10.4 dBm to 0.2 dBm without gain reduction and noise penalty while requiring only an extra current of 0.1 mA.

A high linearity and high gain Folded Cascode LNA for narrowband receiver applications

“…Hence, DS method is not effective in reducing the IM3. To reduce IM3, MDS technique is proposed in [5]. Fig.…”

“…Moreover, the second order nonlinearity transconductance component (g m2 ) is large at this point, which may contribute to third order intermodulation component (IM3) due to source degeneration feedback. Externally generated second order intermodulation component (IM2) is added in [5] for cancellation of the nonlinearity at the output. But, due to IM2 generator there is significant noise contribution for single ended LNA.…”

Mixer Linearization by Modified Baseband Signals

“…Various techniques for the linearization of the mixer (Ellis, 1998;Kim et al, 2002;Liang et al, 2008) have been proposed in the literature, such as feedforward, predistortion, a technique based on transconductance cancelation of the third-order, techniques based on the insertion of the second harmonic and/or the difference frequency signal in the analog domain (Ock et al, 2001;Lou et al, 2008;Theodoratos et al, 2007). This paper analyses the impact of the two different linearization techniques that use the modified signals in the baseband in order to linearize the mixer used as a downconverter (Atanasković et al, 2013(Atanasković et al, , 2015.The modified baseband signal is the product of the secondorder nonlinearity of a nonlinear system induced by the useful baseband signal.…”

Design of a Electrically Tunable Filter for RF Front-end Circuitry of the Microwave Receiver

“…If both ends of the variable capacitance diode reverse bias are changed, the capacitance value of the variable capacitance diode will change too. So the center frequency of the filter will change, the change in frequency can be quickly tracked [4]. This paper presents a design scheme of a 225 to 500 MHz electrically tunable filter.…”