230328: wband rcvr s-parameters



    The sparameters for cal input to dewar output were measured by  felix on  10feb23. This had the dewar as delivered by hamdi.
     The s11 measurements showed reflections from the 2 sections of cal cable that went from cal input to cal coupler. These cables were standard sma cables. These measurements also included a 10db pad at the input to the cal coupler (at 20K).

    Felix/carlos replaced the 2 sections of sma cable with a single stainless steel cable. This should remove the closer reflections (from the first section of cable). It should also help with the dewar temp since the stainless steel cables would conduct less heat. They also removed the 10db pad that was in front  of the cal coupler. If we had reflections  from the input to the cal coupler, you would expect S11 to increase (by at least 10db).

    On 28mar23 felix remeasured the s-parameters in the lab with the dewar cold (after the stainless steel cal cable was installed, and the 10db pad removed). The setup was:

The S-parameters:

    Plots show the

    The plots show the measured s-parameters (.ps) (.pdf):


processing: x101/230328/sparmswbrcv.pro

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