INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Reduction of the Uncertainty on Noise Figure Measurements A. Cremonini 1, M. De Dominicis 2, S. Mariotti 1 , E. Limiti 3, A.Serino 3 1 INAF – Institute of Radioastronomy- Bologna – Italy 2 Elettronica s.p.a. – V. Tiburtina Valeria, Rome – Italy 3 University “Tor Vergata” – Electronic Eng. Dept. – Rome - Italy Sergio Mariotti s.mariotti@ira.inaf.it Göteborg, jun 19th 2006

WHY Reduce Uncertainty? INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHY Reduce Uncertainty? +/- 3.5 % = +/- 0.15 dB For a receiver: NF = 0.3 +/-0.15 dB Te = 21 +/- 11 K Uncertainty should be much lower than the value to be measured Sergio Mariotti Göteborg, jun 19th 2006

How Reduce Uncertainty? INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME How Reduce Uncertainty? Looking for and Find Sources of Uncertainty (U) Minimize the sources wherever it is possible Analyze and propagate uncertainty Since U(ENR) is dominant, let do calibration of Noise Source with a Secondary Standard (liq. N2) Walking steps Looking for and Find Sources of Uncertainty Analyze and propagate uncertainty Minimize were possible that sources Will be shown that U(ENR) is dominant Comparison with a Secondary Standard (liq. N2) Let Practical operations accurate as possible Let Practical operations accurate as possible Sergio Mariotti Göteborg, jun 19th 2006

Involved Environments INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Involved Environments Room Temperature Cryogenic /on Dewar - easier - faster - accurate - less jitter - more realistic - accurate Sergio Mariotti Göteborg, jun 19th 2006

Sources (causes) of Uncertainty: Propagation, Math Formulation INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Sources (causes) of Uncertainty: Propagation, Math Formulation F12 F2 = 10dB F1 = 3 dB G1= 15 dB Depend on many causes, even U(ENR) Depend on U(ENR) Sergio Mariotti Göteborg, jun 19th 2006

Causes of Uncertainty: Graphical - Intuitive INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Causes of Uncertainty: Graphical - Intuitive Te Tc Th Pc Ph Te Tc Th Pc Ph Te Tc Th Pc Ph Reducing Tc, will reduce U(Te) Reducing U(Th) and U(Tc) will reduce U(Te) Increasing Th don’t reduce U(Te) , because U(Th)/Th is a constant Instead increase Th may generate non-linearity . Yopt 2…5 Sergio Mariotti Göteborg, jun 19th 2006

Causes of Uncertainty: Practical, Tips&Tricks INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Causes of Uncertainty: Practical, Tips&Tricks |S11 ON| , |S11 OFF| < - 33 dB Selected Attenuator PT 100 A 10 dB 6 dB Cascade Ferrite Isolators Precision Connectors / Connector Care NO cables movement Environment: Thermostatic room, Type A Uncert. << Type B Uncert. Sergio Mariotti Göteborg, jun 19th 2006

Other causes of Uncertainty: INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Other causes of Uncertainty: Mismatch: A closed form expression doesn’t exist Approximate Expression rNS rDUT Sergio Mariotti Göteborg, jun 19th 2006

Principle of Operation 1/3 INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Principle of Operation 1/3 Liq. N2 77 K POWER METER 800 mW Liq. N2 77 K POWER METER 9400 mW Liq. N2 77 K POWER METER 3200 mW Liq. N2 77 K POWER METER 9400 mW Liq. N2 77 K POWER METER 800 mW Liq. N2 77 K POWER METER 3200 mW Noise Source + Attenuator Sergio Mariotti Göteborg, jun 19th 2006

Principle of Operation 2/3 INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Principle of Operation 2/3 Vector Correction Sergio Mariotti Göteborg, jun 19th 2006

Pictures Coaxial 1-18 GHz WR 28 26.5-40 GHz WR 22 33-50 GHz INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Pictures Coaxial 1-18 GHz WR 28 26.5-40 GHz WR 22 33-50 GHz Sergio Mariotti Göteborg, jun 19th 2006

MatLab® codes has been used to: INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Data Analysis MatLab® codes has been used to: Process spar of non insertable Adapter Compute Mismatch and Available Gain Instruments control and automatic data collection Calculate ENR and associated Uncertainty Sergio Mariotti Göteborg, jun 19th 2006

Uncertainty of the Result INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Uncertainty of the Result Depend on U(Tcryo) S par Uncertainty S par Uncertainty Uncertainty of VNA is dominant ( 0.045 dB - hp 8510C ) Sergio Mariotti Göteborg, jun 19th 2006

Results and Associated Uncertainty INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Results and Associated Uncertainty U(ENR) was +/- 0.15 dB U(ENR) = +/- 0.06 dB Sergio Mariotti Göteborg, jun 19th 2006

Spin-off for the LNAs INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Spin-off for the LNAs Sergio Mariotti Göteborg, jun 19th 2006

WHAT can we do ? 1/3 No possibility to further reduce ENR Uncertainty INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHAT can we do ? 1/3 No possibility to further reduce ENR Uncertainty … but we may transfer our expertise to reduce ENR Uncertainty of other Noise Sources REQUEST and submit a PROPOSAL Need to share expensive Instruments (CryoLoad) Sergio Mariotti Göteborg, jun 19th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHAT can we do ? 2/3 PROPOSAL: Comparition of Noise Figure Measurement over community (better if even larger) As the IEEE “Round Robin”, an LNA will be sent to European Laboratories to be measured. Each laboratory will perform measurement as usual and according to its own methodology Measured data will be compared and published Sergio Mariotti Göteborg, jun 19th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHAT can we do ? 3/3 LNA Bandwidth has been chosen to be a bridge between the “easy” 1-18 GHz and the “difficult” over 18 GHz. Freq. 16 – 26 GHz, Gain=27dB, NF=1.6 dB (130K) Euro Plug Power Supply LNA Sergio Mariotti Göteborg, jun 19th 2006

Essential Bibliography INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Essential Bibliography [1] J. Randa, “Noise Temperature Measurements on wafer ” NIST Tech. Note 1390 03/1997 [2] Agilent Technologies, “Noise Figure measurement accuracy – The Y-Factor method”, Application Note 57-2, 2001. [3] W.C. Daywitt, “Radiometer equation and analysis of systematic errors for the NIST automated radiometers”, National Institute of Standards and Technology, Technical Note 1327, 03/1989. [4] C.T. Stelzried, “Temperature calibration of microwave thermal noise sources”, IEEE Transactions on Microwave Theory and Techniques (Correspondence), Vol. MTT-13, No. 1, 01/1965, pp. 128-130. [5] R.F. Bauer, P. Penfield, “De-Embedding and Unterminating”, IEEE Transactions on Microwave Theory and Techniques, Vol. 22, No. 3, 03/1974, pp. 282-288. [6] J.D. Gallego, “Accuracy of Noise Temperature Measurement of Cryogenic Amplifiers”, - NRAO Int. Rep. No 285 jan. 1990. Sergio Mariotti Göteborg, jun 19th 2006

Conclusions The ENR of some Noise Sources has been calibrated. INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Conclusions The ENR of some Noise Sources has been calibrated. The Uncertainty related to ENR has been reduced from +/-0.15 dB typ to +/- 0.06 dB typ Waveguide, millimeter cryoloads are needed to improve reliability The calibration routine and the instrumental set-up may be repeated once again. Sergio Mariotti Göteborg, jun 19th 2006

Thanks INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Thanks Sergio Mariotti Göteborg, jun 19th 2006