pss simulation input power

Discussion in 'Cadence' started by tkleeburg, Jun 1, 2007.

  1. tkleeburg

    tkleeburg Guest

    Hi,
    I am running a pss simulation on a few transistors which should act as
    a PA.

    Ive defined 2 ports at the input and output.

    Pin is the power out defined in port 1 under Amplitude (dBm), and the
    input wave is a sine at 1 frequency. there are no other tones defined
    in the port or anywhere else.

    The pss simulation is defined as 1 pss 2.4G 3 -40 0 Large Port1

    I am sweeping the input power(Pin) out of port 1 over a some range.The
    output power of port 1 is at least 5 dBm higher than the input power
    and it has spectral components. This only happens if i choose terminal
    or port (fixed (R)). The higher output occurs if i choose port (fixed
    (R)) but i get a lower output if I choose terminal.

    I assumed that it might be modeling spectral regrowth which takes care
    of the spectral components but not the power. the power i am
    referring to is at the fundamental frequency.


    If i change the simulation variable to lets say the width of some
    transistor and fix the input power Pin to be constant. Then if I plot
    the power out of port 1 vs the width it changes again as a function of
    the width when it should be constant. I am really confused on how the
    power out of the port is defined and how it can change.



    I am guessing that terminal is calculation the input power using 1/2
    VxI*. And that fixed R(port) assumes equal impedances for the source
    and the input of the PA so the power is something like Pav= V^2/
    (4*Rport)? I ask this because ideally i would like to provide pulse
    input and i need to be able to accurately measure the power out of the
    port.


    Secondly I am having a hard time doing a source pull simulation. I am
    using the port adapter block, this works fine at the output but I
    think that the simulation cant find a solution at a specific value of
    theta because its causing the device to break down. When i simulate
    this directly using the traffic light it works fine and I get a bad
    data point at the angle stated in the log file but when I run a
    parameter sweep i cant get any output data.

    Will the convergence techniques in the pss convergence post help? I
    tried avoiding the point by placing it in the middle of 2 points that
    are somewhat far apart but this didnt work.



    Any help with this will be greatly appreciated
    Thanks
    Travis
     
    tkleeburg, Jun 1, 2007
    #1
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