Stats

  • Locked Locked
  • Replies 4
  • Subscribers 63
  • Views 15885
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Measureing INPUT impedance of the Passive Switching Mixer

RFQuery

 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

 

Parents

  •  Thanks Andrew

    I wanted to give the attachemts of Schematic and the LOG file but unfortunately this forum does NOT have option to attach files.

    Finally I found what is the issue. It turns out that My IDEAL switch parameters settings were wrong. So they were always OFF.I did the proper setting of the switches and got 50 Ohm at the RF side.

    As suggested by you PSS has some issues with delay elements. If I want to have N-path (say 8 paths) switches and all are driven by multiphase (delayed) pulse sources, don't you think it is also a problem for PSS analysis as it has to Handle 8 driven Large Signal Sources.

    If it is a problem, then in this scenario what can be done to have multiphase/delayed clocks in the simulation.

    Thanks-

     

Reply

  •  Thanks Andrew

    I wanted to give the attachemts of Schematic and the LOG file but unfortunately this forum does NOT have option to attach files.

    Finally I found what is the issue. It turns out that My IDEAL switch parameters settings were wrong. So they were always OFF.I did the proper setting of the switches and got 50 Ohm at the RF side.

    As suggested by you PSS has some issues with delay elements. If I want to have N-path (say 8 paths) switches and all are driven by multiphase (delayed) pulse sources, don't you think it is also a problem for PSS analysis as it has to Handle 8 driven Large Signal Sources.

    If it is a problem, then in this scenario what can be done to have multiphase/delayed clocks in the simulation.

    Thanks-

     

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.