2. Sergio Mariotti s.mariotti@ira.inaf.it Göteborg, jun 19 th 2006 INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME 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 Reduction of the Uncertainty on Noise Figure Measurements Reduction of the Uncertainty on Noise Figure Measurements A. Cremonini 1, M. De Dominicis 2, S. Mariotti 1, E. Limiti 3, A.Serino 3

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

4. Sergio Mariotti Göteborg, jun 19 th 2006 INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Looking for and Find Sources of Uncertainty (U) How Reduce Uncertainty? Analyze and propagate uncertainty Minimize the sources wherever it is possible Since U(ENR) is dominant, let do calibration of Noise Source with a Secondary Standard (liq. N 2 ) Let Practical operations accurate as possible

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

6. 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 2 = 10dBF 1 = 3 dB G 1 = 15 dB Depend on many causes, even U(ENR)Depend on many causes, even U(ENR) Depend on U(ENR)

7. Sergio Mariotti Göteborg, jun 19 th 2006 INSTITUTE OF RADIOASTRONOMY, - ITALY UNIVERSITY “TOR VERGATA” - ROME Causes of Uncertainty: Graphical - Intuitive TeTe TcTc ThTh PcPc PhPh TeTe TcTc ThTh PcPc PhPh Reducing T c, will reduce U(T e ) TeTe TcTc ThTh PcPc PhPh Reducing U(T h ) and U(T c ) will reduce U(T e ) Increasing T h don’t reduce U(T e ), because U(T h )/T h is a constant Instead increase T h may generate non-linearity. Yopt 2…5

8. 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 dB Selected Attenuator PT 100 A Cascade Ferrite Isolators Environment: Thermostatic room, NO cables movement Precision Connectors / Connector Care Type A Uncert. << Type B Uncert. 10 dB6 dB

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

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

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

12. 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

13. Sergio Mariotti Göteborg, jun 19 th 2006 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

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

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

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

17. 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 (CryoLoad)

18. 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

19. Sergio Mariotti Göteborg, jun 19 th 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) LNA Power Supply Euro Plug

20. 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.

21. 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 dB typ to +/- 0.06 dB typ The calibration routine and the instrumental set-up may be repeated once again. Waveguide, millimeter cryoloads are needed to improve reliability

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