LNA circuit not working
Vgate of M1 is at VDD, that, together with the voltage drop across M2 forces it into linear mode. You want to use M1 in saturation mode. I would use something like this to have better control over the DC biasing current through M1:







simulate this circuit &ndash; Schematic created using CircuitLab

Note how M1bias and M1 form a current mirror, this allows me to directly set the DC biasing current through M1 by setting the value of I1.

R1 is a high impedance for the RF signal so M1bias doesn't see the RF signal. All RF signal goes to M1, which is what we need.

I biased the gate of the cascode transistor Mcasc with a separate DC voltage source. That way I can easily play with the value (in your circuit it is always VDD which is less flexible).

Note how I use C1 and C2 (both 1 nF) to block the DC signals. This works two ways, the LNA circuit isn't disturbed by any DC voltages at the input source or the output. The inputs and outputs will have a DC voltage of 0 V.

Small point: Ca does nothing in your circuit, it is directly in parallel with the the 1.8 V DC power supply which is an ideal voltage source so Ca will have 1.8 V DC across it as that is forced by the DC source. If you want to model the effect of a supply with an internal resistance then add resistor in series with the 1.8 V DC source and the Ca will help as it will decouple the VDD line to GND.