Hello aashishsharma, here's an attempt to answer your questions. I may also raise some questions on the method you chose.
- I assume you wish to see that HB and AC simulations treat a linear circuit in exactly the same way. In fact, what is happening inside the HB simulator in the case of a completely linear circuit is just AC analysis, so you should indeed get the same results.
- During HB simulation, do you use the "RF_freq" variable to perform a frequency sweep? Do you do this inside the "Sweep" tab of the HB simulator? Shouldn't you set the input source frequency to vary with the "RF_freq" variable to obtain a meaningful result?
- When performing a frequency sweep, it is better to compare the results over frequency, rather than time. The time domain signal you obtain during AC sweep is rather meaningless in the way you want to use it. To see this, change the step of the frequency sweep to 100 MHz, 2 GHz etc. and see what happens. It is just an inverse Fourier Transform of the flat "Vin" vs. "freq" response, and the inverse FT of a flat frequency response is an impulse, right? However, the position of the impulse in time will change depending on where you set the step frequency (it will be 1/Fstep).
- Instead, compare "Vout" vs. "freq" (of the fundamental tone, in HB case) for each analysis. You will see that the results will match.