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SUPERCAM SINGLE PIXEL BLOCK MEASUREMENTS HAMDI MANI 09/12/2008

SUPERCAM SINGLE PIXEL BLOCK MEASUREMENTS HAMDI MANI 09/12/2008. LNA with an open input. Open LNA input SIS Device not mounted yet. Detailed view of the IF part of the single pixel Mixer Block. Top Cover Of the LNA. Output cover Of the LNA. Flange connector (2.92mm )

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SUPERCAM SINGLE PIXEL BLOCK MEASUREMENTS HAMDI MANI 09/12/2008

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  1. SUPERCAM SINGLE PIXEL BLOCK MEASUREMENTS HAMDI MANI 09/12/2008

  2. LNA with an open input

  3. Open LNA input SIS Device not mounted yet

  4. Detailed view of the IF part of the single pixel Mixer Block Top Cover Of the LNA Output cover Of the LNA Flange connector (2.92mm ) (can’t find SMA which fits for the Center pin of the 047 SR coax.) 047SR coax Grounded using H20E epoxy

  5. “Home made” LNA output cover ! Sealed with epoxy . Temporary fix to make Sure we are fixing the problem and to make next version drawings of the LNA chassis . Notch on the LNA cover left open . DC Lines are well bypassed and very well isolated from LNA RF output Board by a wall on the LNA cover

  6. 300K Data : output return Loss of the LNA (open input)

  7. 20 K Data : output return Loss of the LNA (open input) The output spectrum (up to26GHz) doesn’t show any sign of oscillations@20K at Very high bias (up to 60mA ) with an open input (device not yet installed)

  8. LNA with an SIS device at the input

  9. H_22_+ SIS device mounted on the single pixel WAFER # T3-215-KWL2 Rn @300K was measured : (Keithley2400 SourceMeter)

  10. LNA #SC00 Chip#R6C1M9 (CIT-077 wafer) Pinch off test at 300K : Vd=0.1V Vg Id 0 1.75mA -0.5 0.7 -1 230uA -2 22 -2.5 9uA This test must be performed When in doubt about the LNA . 300K Bias : Vd=1.8V Id=50mA Vg=1.6V 20K Bias: Vd=1V Id=10mA Vg=1.6 Input and DC notches on the LNA cover are Left. Do not affect the feedback problem . The input notch allows bonding the SIS with the cover ON . Indium foil under the LNA base to improve the grounding H_22_+ SIS device

  11. Some Notes about the package • The Coax confines the fields better than the microstrip ,S12 is measured -50 with • the supercam LNA on a test fixture . • The cover at the output of the LNA improves the isolation , this is a temporary fix • And a new cover can be implemented in the base of the LNA . • ALL the modifications done on the single pixel block can be removed • (cable ,epoxy ,IF board …. ) and the block can be re-used .

  12. 300K Data : output Return Loss of the block (SIS at the input) No oscillations seen at room temperature at high bias , SIS connected to the input of the LNA . No positive return Loss .

  13. 17K Data: output return Loss (SIS input ) , Horn mounted The LNA was biased at high current up to 55mA with no oscillations up to 40GHz. No positive return Loss . The ripple on the curve is due to calibration (cal performed at 300K inside the cryostat)

  14. Supercam Single Pixel block inside our “busy” “All purpose” 20K cryostat Supercam 1pixel Block bolted to the 20K stage ,output Connected to Spectrum Analyzer / VNA

  15. Possible implementations of the “semi rigid coax” at the LNA output LNA base is the only part that needs modification LNA tested by mounting it on a 50 ohm test fixture and bonding the input to a 50 ohm Microstrip to coax transition .

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