Impact of adapters on LISN's input impedance calibration: How to improve accuracy and reliability of the measurements? Part 2

Transcription

1 Impact of adapters on LISN's input impedance calibration: How to improve accuracy and reliability of the measurements? Part 2 François. ZIADE, Miha. KOKALJ Workshop EMC Europe 2016

2 Outline Objective : measuring the true input impedance Setup and VNA calibration process Correction calculation Results Published Papers 2

3 Objective : measuring the true input impedance LISN : Measurement of input impedance Z LISN The input impedance has to be measured at EUT port: Between each line and RF ground Between neutral and RF ground Measurement setup: Adapter Coaxial - bifilar VNA EUT port LISN LISN: single phase 50 Ω load RF port 3

4 Setup and VNA calibration process 3 steps: calibration, reflection coefficient Γ in measured and input impedance Z in calculated Open Short Load (OSL) calibration [9 khz 30 MHz] MATLAB & LABVIEW Γ IN Rohde & Schwarz ESH3-Z5 ESH2-Z5 Adapters for ESH3-Z5 And ESH2-Z5 4

5 Correction calculation Import data into Excel file Calibration plane 1 2 Measurement plane Γ LISN?? S S ( S ) = S21 S22 VNA Coax-à-bifil adaptateur Γ in obtained by measurement Charge 50 Ohm Γ in 50 Ω load EUT port RF port LISN (S) of the adapter Stored into a specific Excel File Γ LISN = S 22 S 11 Γ in ( S ) 11 Γin S12S21 Correction calculation performed using a specific Excel file 5

6 Correction calculation Import data into Excel file 6

7 Correction calculation S matrix of each adapter calculated at each frequency S matrix of the adapter Type B uncertainty of Zin: Magnitude and phase 7

8 Correction calculation Correction applied to Z in at each frequency Magnitude and phase corrected 8

9 Correction calculation Summary of the results at each frequency 9

10 Results Measurements with three different types of adapters 10

11 Results Measurements with three different types of adapters At 30 MHz the maximum deviation is around 10 between adapters Phase ( ) Frequency (MHz) 11

12 Results Measurements of ESH3 Z5 (Rohde & Schwarz) Limits of CISPR Result of input impedance phase Phase ( ) 30 MHz Nominal values of CISPR Frequency (MHz) 12

13 Results Measurements of ESH3 Z5 (Rohde & Schwarz) Result of input impedance magnitude Limits of CISPR Nominal values of CISPR Magnitude (Ω) Frequency (MHz) 30 MHz 13

14 Results Measurements of ESH3 Z5 (Rohde & Schwarz) Deviation between uncorrected and corrected results Magnitude deviation (Ω) Uncertainties obtained without correction Uncertainties obtained with correction Deviation between corrected and uncorrected values Frequency (MHz) 14

15 Results Measurements of ESH3 Z5 (Rohde & Schwarz) Deviation between uncorrected and corrected results Deviation between corrected and uncorrected values Phase ( ) Uncertainties obtained with correction Uncertainties obtained without correction Above 25 MHz the deviation between uncorrected and corrected results are bigger than uncertainties Frequency (MHz) 15

16 Results Measurements of ESH2 Z5 (Rohde & Schwarz) Deviation between uncorrected and corrected results Magnitude deviation (Ω) Uncertainties obtained with correction Deviation between corrected and uncorrected values Uncertainties obtained without correction Frequency (MHz) 16

17 Results Measurements of ESH2 Z5 (Rohde & Schwarz) Deviation between uncorrected and corrected results Deviation between corrected and uncorrected values Phase ( ) Uncertainties obtained with correction Uncertainties obtained without correction Above 13 MHz the deviation between uncorrected and corrected results are bigger than uncertainties Frequency (MHz) 17

18 Results Difference between ESH2-Z5 and ESH3-Z5 measurement results Deviation between uncorrected and corrected results = 2.4 Deviation between uncorrected and corrected results = 5.5 The length of ESH2-Z5 adapter is longer than ESH3-Z5 adapter 18

19 Published Papers EMC Europe 2015: Adapter and method for improving the LISN input impedance measurement accuracy (POSTER) F. ZIADÉ, M. OUAMEUR, D. BÉLIÈRES, A. POLETAEFF, D. ALLAL, M. KOKALJ, B. PINTER, Adapter and method for improving the LISN input impedance measurement accuracy, 2015 IEEE International Symposium on Electromagnetic Compatibility (EMC), Dresden, Germany, Aug. 2015, pp Paper accepted in IEEE Transactions on Instrumentation and Measurements (August 2015): Improvement of LISN Measurement Accuracy Based on Calculable Adapters F. ZIADÉ, M. KOKALJ, M. OUAMEUR, B. PINTER, D. BÉLIÈRES, A. POLETAEFF, D. ALLAL, Improvement of LISN Measurement Accuracy Based on Calculable Adapters, IEEE Transactions on Instrumentation & Measurement, Vol. 65, pp , Feb