1. 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 Göteborg, jun 19th 2006

2. WHY Reduce Uncertainty?
INSTITUTE OF RADIOASTRONOMY, - ITALY
UNIVERSITY “TOR VERGATA” - ROME
WHY Reduce Uncertainty?
+/- 3.5 % = +/ 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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
GHz
WR 22
33-50 GHz
Sergio Mariotti Göteborg, jun 19th 2006

12. 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

13. 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 ( dB - hp 8510C )
Sergio Mariotti Göteborg, jun 19th 2006

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

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

16. 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

17. 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

18. 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

19. Essential Bibliography
INSTITUTE OF RADIOASTRONOMY, - ITALY
UNIVERSITY “TOR VERGATA” - ROME
Essential Bibliography
[1] J. Randa, “Noise Temperature Measurements on wafer ” NIST Tech. Note /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
[5] R.F. Bauer, P. Penfield, “De-Embedding and Unterminating”, IEEE Transactions on Microwave Theory and Techniques, Vol. 22, No. 3, 03/1974, pp
[6] J.D. Gallego, “Accuracy of Noise Temperature Measurement of Cryogenic Amplifiers”, - NRAO Int. Rep. No 285 jan
Sergio Mariotti Göteborg, jun 19th 2006

20. 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 +/ 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

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