LTSPICE

Hi Hugh, I checked with my colleagues in the LTSpice group and they confirmed that you cannot simulate an RF amplifier in LTSpice. LTSpice is an analog domain simulator that is at home with voltage and time domain simulations of devices such as operational amplifiers which have high input impedance and low output impedance. HMC311 is an RF amplifier with with input and output impedance of 50 ohms and behavior that is best modelled in the logarithmic power domain (e.g. output power in dBm, gain and noise in dB). So there are no structures in place in LTSpice to support rf components such as an RF Amplifier. 

I think that if you wanted to, you could build a basic model from scratch. You would start with a block of gain. At the input you would add a 50 ohm resistor to ground. And at the output, you would add a 50 ohm series resistor to give the device and output resistance of 50 ohms. If you need to model HMC311 in your system to complete the signal chain, something like this might work. 

Best Regards

Eamon Nash

Hi again Hugh,

I need to correct myself. It seems that there is a process to pull s-parameter datasets into LTSpice. See the thread below which links to an external groups.io group where a process is described. I have not tried this but I would like to at some point becuase the question comes up from time to time.

Best Regards

Eamon

https://ez.analog.com/design-tools-and-calculators/ltspice/f/q-a/596956/modelling-rf-amplifiers-in-ltspice