*3.1. LNTA Design*

Conventionally, a wideband low noise amplifier (LNA) is used followed by a *gm*-stage, down-conversion mixer and transimpedance amplifier (TIA). This helps reduce the NF but also amplifies blockers, which can saturate the following stages of the receiver[18]. The LNTA is an alternative that can be used to convert the RF voltage to an RF current that is then down-converted to the IF or BB current through a passive mixer. In this fashion, the receiver is not compressed by blockers due to the inherent low-voltage gain [15]. This work employs a low noise and wideband LNTA proposed in [19], shown in Figure 3.

**Figure 3.** LNTA circuit diagram.

The first transconductance stage (*gm*0) provides the input impedance matching, which is given by

$$Z\_{in} \cong \frac{1}{\mathcal{g}m\_0} (1 + R\_0/r\_0) \tag{3}$$

where *R*<sup>0</sup> is the feedback resistor and *r*<sup>0</sup> is the output resistance of the *gm*<sup>0</sup> circuit.

Thanks to the feed-forward technique that provides noise-cancellation, the LNTA can achieve a low NF given by

$$NF \cong 1 + \frac{gm\_2}{gm\_1} + \frac{\lambda}{gm\_1R\_s} \tag{4}$$

where *λ* is the short-channel effect coefficient, which can be reduced by increasing the transistor lengths. It can be seen the NF is independent of *gm*<sup>0</sup> and can be reduced by increasing the *gm*<sup>1</sup> value.

The total transconductance gain is approximated and given by

$$G\_m \cong \frac{1}{2} \left[ \left( \frac{gm\_0 R\_0 - 1}{1 + R\_0/r0} \right) gm\_2 + gm\_1 \right] \tag{5}$$

Transconductance *gm*<sup>0</sup> provides gate biasing for the *gm*<sup>1</sup> and *gm*<sup>2</sup> inverters along with bulk biasing of the PMOS and NMOS transistors since flip-well devices are used in a fully depleted silicon on insulator (FDSOI) CMOS technology. This reduces the area and parasitic capacitance of the AC-coupling capacitors at the input of *gm*<sup>1</sup> and *gm*2.
