Noise Figure in N-path band pass filter using PSS/Pnoise

Hi everybody,

I am using Pss/Pnoise to simulate NF of a 4-path band pass filter. In term of theory, this NF is medium around 5 to 10 dB depending on the switching frequency, which is 

contributed by thermal noise of source resistance, switch resistance and noise folding from other harmonics of switching frequency., flicker noise is supposed to be neglected because there is no DC current from port 1 to port 2

However, the simulation is a little weird to me (it is around 27 dB at 2.41 GHz - center frequency of filter). 

Is there any wrong here, could you help to figure out some possible reasons? (any culprit that is able to fold the flicker noise into the desired band, because there is a peak in simulation result) 

my circuit infor: it has a divider/4 from 9.64 GHz to 2.41 GHz controls cmos switches 

input: 2.41gHz 

output 2.41 GHz 

insertion loss: around 5 dB 

source resistance: 50 ohm at two port  

here is my setting for pss/pnoise: 

thanks for any advice.

Binh Ngo