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NRAO Millimeter/THz Development Program: Current and Future. ALMA Development. ALMA Development Workshop (March 21-22) Band 3 (or Band 2/3) MMIC LNA Upgrade Band 6 Balanced Mixer Upgrade SIS Mixer Development for Band 10 and beyond Focal Plane Arrays. Band 3 (or 2/3) LNA Upgrade.
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ALMA Development ALMA Development Workshop (March 21-22) Band 3 (or Band 2/3) MMIC LNA Upgrade Band 6 Balanced Mixer Upgrade SIS Mixer Development for Band 10 and beyond Focal Plane Arrays Millimeter/THz Development at the NRAO CDL
Band 3 (or 2/3) LNA Upgrade Using 35nm InP HEMT MMIC LNA 67-90 GHz 1st iteration (EBLNA81) New designs funded by KISS (Keck Institute for Space Studies): EBLNA81B, EBLNAW+, EBLNAW0, MMLN100 Fabrication complete, diced chips expected in ~2 weeks ~25% Sensitivity Improvement for Band 3 M. Morgan has designed a MMIC Schottky “SIS-substitute” mixer Directly applicable to GBT 3mm FPA Could also be used as W-band IF LNA for SIS or Schottky mixer Millimeter/THz Development at the NRAO CDL
EBLNA81B: Retuned for 67-90 GHz L13: 65 to 34um L14: 78 to 144um L13 L14 Millimeter/THz Development at the NRAO CDL
EBLNAW+: Cover full 68-116 GHz band Millimeter/THz Development at the NRAO CDL
MMLN100: Cover full 68-116 GHz band Millimeter/THz Development at the NRAO CDL
EBLNAW0: A “Tunable” MMIC LNA Millimeter/THz Development at the NRAO CDL
UVML/NRAO/UAz SIS Collaboration 5 year program funded by ALMA Operations, beginning FY09 Advanced Materials and Processing Techniques AlN Barriers for Wide Bandwidth (and NbTiN) Nb/AlN/NbTiN SIS Junction Development (up to ~1.2 THz) Superconducting Hybrid Development (UAz funded) 0.7mm and 0.35mm Balanced/Sideband-Separating Mixers >1THz SIS Mixers (for SOFIA, ALMA Band 11, etc.) Balanced SIS Mixer for Band 6 (IF bandwidth to 4-12 GHz) Millimeter/THz Development at the NRAO CDL
SIS Materials and Processing Development Nb/AlN/NbTiN SIS mixers with AlN barriers are expected to yield near quantum-limited noise up to 1.2 THz Characterization of NbTiN film properties at 4K Used cryogenic probe station to measure capacitance and penetration depth (surface inductance) Will improve accuracy of mixer designs Delivery of hot deposition system in Jan. 2010 Single crystal Nb tuning circuits NbTiN with higher Tc New materials… Millimeter/THz Development at the NRAO CDL
Silicon Membrane Beamlead Circuits • 3mm thick Silicon substrate • Can be cut to arbitrary shape • Can be patterned with Nb or NbTiN • Beamleads allow for easy and repeatable assembly • Used in current design of 700mm SIS mixer chips and superconducting 3dB hybrid chips Millimeter/THz Development at the NRAO CDL
Drop-In Superconducting Hybrids For easy design and assembly of balanced and sideband-separating mixer modules 375-500 GHz (WR-2.1) prototype Works as expected at room temperature, currently being measured cold UVML funding partly from UAz 287 mm Millimeter/THz Development at the NRAO CDL
Balanced SIS Mixers Rejection of LO noise 50-100 times less LO power 3dB greater dynamic range Currently processing 375-500 GHz prototype using Nb/AlN/Nb SIS mixer and superconducting hybrid SIS Mixer Superconducting 180° IF Hybrid Superconducting 3dB RF Hybrid IF Output SIS Mixer Millimeter/THz Development at the NRAO CDL
Sideband-Separating SIS Mixers Reject atmospheric noise in other sideband Eliminate need for LO frequency switching to identify spectral lines Below is shown a balanced and sideband-separating SIS mixer Superconducting 3dB RF Hybrids Absorbing Load SIS Mixer SIS Mixer LSB IF Output USB IF Output SIS Mixer SIS Mixer Superconducting 180° IF Hybrids Millimeter/THz Development at the NRAO CDL
UVML/NRAO/UAz SIS Collaboration:Recent Highlights Factor of 10 improvement (from +/- 2 Ang. to +/- 0.2 Ang.) in repeatability of AlN thickness using new ICP growth protocol and rebuilt Succesful implementation of single-resist junction process, quicker and more repeatbale than pentablevel process Precise measurements of Nb and NbTiN films London penetration depth Room temperature verification 385-500 GHz superconducting hybrid on high-conductivity silicon membrane Millimeter/THz Development at the NRAO CDL
UVML/NRAO/UAz SIS Collaboration:Development Plan March 2011: Repeatable Jc on Nb/Al-AlN/Nbtrilayer test circuits May 2011: 385-500 GHz SIS wafer complete June 2011: Single-ended and balanced 385-500 GHz SIS mixer measured Summer 2011: Nb/Al-AlN/NbTiNtrilayer tests followed by band 10 SIS fabrication Fall 2011: Testing of sputtered Nb/AlN/NbTiN, NbTiN/AlN/NbTiN, hot-deposited NbTiNtrilayers Millimeter/THz Development at the NRAO CDL