INSTITUTE OF RADIOASTRONOMY ITALY UNIVERSITY TOR VERGATA ROME

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 2 3 INAF – Institute of Radioastronomy- Bologna – Italy Elettronica s. p. a. – V. Tiburtina Valeria, Rome – Italy University “Tor Vergata” – Electronic Eng. Dept. – Rome - Italy Sergio Mariotti s. mariotti@ira. inaf. it Göteborg, jun 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHY Reduce Uncertainty? +/- 3. 5 % = +/- 0. 15 d. B For a receiver: NF = 0. 3 +/-0. 15 d. B Te = 21 +/- 11 K Uncertainty should be much lower than the value to be measured Sergio Mariotti Göteborg, jun 19 th 2006

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. N 2) • Let Practical operations accurate as possible Sergio Mariotti Göteborg, jun 19 th 2006

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

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Sources (causes) of Uncertainty: Propagation, Math Formulation F 12 F 1 = 3 d. B G 1= 15 d. B F 2 = 10 d. B • Depend on many causes, even U(ENR) Depend on U(ENR) Sergio Mariotti Göteborg, jun 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Causes of Uncertainty: Graphical - Intuitive Ph P Pcc Te Tc Tc Th 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 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Causes of Uncertainty: Practical, Tips&Tricks |S 11 ON| , |S 11 OFF| < - 33 d. B Selected Attenuator PT 100 A 6 d. B Cascade Ferrite Isolators Precision Connectors / Connector Care NO cables movement Environment: Thermostatic room, Type A Uncert. << Type B Uncert. Sergio Mariotti Göteborg, jun 19 th 2006 10 d. B

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

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Principle of Operation 1/3 9400 3200 800 m. W Liq. N 2 77 K POWER METER Noise Source + Attenuator Sergio Mariotti Göteborg, jun 19 th 2006

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

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 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Data Analysis Mat. Lab® 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 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Uncertainty of the Result Depend on U(Tcryo) S par Uncertainty of VNA is dominant Sergio Mariotti ( 0. 045 d. B - hp 8510 C ) Göteborg, jun 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Results and Associated Uncertainty U(ENR) was +/- 0. 15 d. B U(ENR) = +/- 0. 06 d. B Sergio Mariotti Göteborg, jun 19 th 2006

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

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 (Cryo. Load) Sergio Mariotti Göteborg, jun 19 th 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 19 th 2006

INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME WHAT can we do ? • LNA Bandwidth has been chosen to be a bridge between the “easy” 1 -18 GHz and the “difficult” over 18 GHz. 3/3 Euro Plug Power Supply LNA • Freq. 16 – 26 GHz, Gain=27 d. B, NF=1. 6 d. B (130 K) Sergio Mariotti Göteborg, jun 19 th 2006

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 19 th 2006

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 d. B typ to +/- 0. 06 d. B 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 19 th 2006

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