Hi All,

I want to plot the input impedance ( in RF Port side) of a passive switching Mixer [2-Phase i.e. 2- 180 degree out of phase non-over lapping LOs with rise and fall time of 1 fs & Two switches Loaded with Resistors of 50 Ohm at the IF ports] with respect to Frequency.

LO frequency was kept 1 GHz and the RF input frequency is swept from 0 to 5 GHz. The RF port impedance is kept at 50 ohm. Also I used analogLib delay element to generate 180 degree out-of pahse 2nd LO.

From theory I know this input impeadnce at the RF port will be a Frequency translated version of the IF side Impedance. But since I am using simple resistor at the IF side the RF side impedance will be the same resistor i.e 50 Ohm

I did PSS and PSP analysis and then I plotted the S11 but I got 0dB across the frequency instead of getting a very large -ve value !!

Can anybody please tell me Where I am going wrong in doing the simulation ?

My Netlist is as Below:--

// Library name: PASSIVE_MIXER

// Cell name: IN_IMPEDANCE

// View name: schematic

V0 (net7 0) vsource type=pulse pacmag=1 pacphase=0 val0=1 val1=0 period=1n \

delay=0 rise=1f fall=1f width=500.0p

PORT0 (net1 0) port r=50 num=1 type=sine freq=frf dbm=prf fundname="rf"

DELAY0 (net033 0 net7 0) delay td=500.0p gain=1.0

R1 (IF_N 0) resistor r=50

R0 (IF_P 0) resistor r=50

SW1 (IF_N net1 0 net033) relay vt1=0 vt2=1 ropen=1T rclosed=1.0

SW2 (IF_P net1 0 net7) relay vt1=0 vt2=1 ropen=1T rclosed=1.0

simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=27 \

tnom=27 scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 \

digits=5 cols=80 pivrel=1e-3 ckptclock=1800 \

sensfile="../psf/sens.output" checklimitdest=psf

pss pss fund=500M harms=51 errpreset=moderate annotate=status

psp psp sweeptype=absolute start=0 stop=5G step=100M

+ portharmsvec=[0] ports=[PORT0] donoise=no annotate=status

modelParameter info what=models where=rawfile

element info what=inst where=rawfile

outputParameter info what=output where=rawfile

designParamVals info what=parameters where=rawfile

primitives info what=primitives where=rawfile

subckts info what=subckts where=rawfile

saveOptions options save=allpub