correlation between radiated immunity and coupling attenuation michiel pelt
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Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
CORRELATION BETWEEN
RADIATED IMMUNITY
AND
COUPLING ATTENUATION
Michiel Pelt
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Introduction
Need for new test method:
No test methods to measure: symmetrical cables, connecting
hardware / cable assemblies balance at higher frequencies combined effect of balance and
screening
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Introduction
Coupling attenuation
New and easy test method to evaluate the EMC performance of channels and components (symmetrical + screened)
Standard prepared by CENELEC TC 46X / WG3: EN 50289-1-6
Under discussion in ISO / IEC JTC1 SC25 WG 3 and CLC TC 215 WG 1
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Introduction
A near field measurement
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Introduction
Simplifications
Device under test: unshielded twisted pair cable coaxial cable dual foil balanced cable
Radiated immunity according to IEC 61000-4-3 fixed position antenna and device
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Coupling attenuation
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Definition coupling attenuation
ac = 10 LOG10 ( P1 ) max [ P2n; P2f ]
ac coupling attenuationP1 input power inner circuitP2n maximum near end peak powerP2f maximum far end peak power
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Limits of coupling attenuation
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Unshielded twisted pair cable
0
30
60
90
120
10 100 1000
FREQUENCY (in MHz)
CO
UP
LIN
G A
TT
EN
UA
TIO
N(i
n d
B)
54 dB
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Coaxial cable
0
30
60
90
120
10 100 1000
FREQUENCY (in MHz)
CO
UP
LIN
G A
TT
EN
UA
TIO
N(i
n d
B)
52 dB
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Coupling attenuation
Dual foil twisted pair cable
0
30
60
90
120
10 100 1000
FREQUENCY (in MHz)
CO
UP
LIN
G A
TT
EN
UA
TIO
N(i
n d
B)
86 dB
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Radiated immunity
Semi-anechoic room (13.2 x 4.7 x 3.0m)Antenna - set-up: 3 mThree amplifiers, two antennas
30 - 200 MHz 200 - 500 MHz 500 - 1000 MHz
Incident field: about 3 V/m (not modulated)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Dimensions cabling set-up
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Justification for cabling set-up
Testing active equipment with cabling (proposal to CISPR G)
Features cabling set-up: gain / frequency response flat polarization not critical direction not critical
(worst case perpendicular to incident field)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Set-up inside semi-anechoic chamber
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Set-up inside semi-anechoic chamber
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Uniform area of cabling set-up
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Field uniformity according to
IEC 61000-4-3
16 points over 1.5 m x 1.5 m surface 75 % values within 0 - 6 dB of nominal
value Field is not constant but uniform
( 83% horizontal; 89 % vertical)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Average field strength
0.0
2.5
5.0
7.5
10.0
0 200 400 600 800 1000
FREQUENCY (MHz)
FIE
LD
ST
RE
NG
TH
(V
/m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Unshielded twisted pair cable
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
-35 dBm
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Coaxial cable
-35 dBm
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Radiated immunity
Dual foil twisted pair cable
-70 dBm
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Conclusions
Conclusion 1: Relative agreement
Same difference between coupling attenuation and induced power for all tested cables
For each test method same deviation between curves for balanced and unbalanced cables using
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Correlation
Gain of set-up
G() = 4 Af()
G( antenna gainAf( antenna aperture wavelength
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Correlation
Unshielded twisted pair cable
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Correlation
Coaxial cable
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Correlation
Dual foil twisted pair cable
-100
-80
-60
-40
-20
0
0 200 400 600 800 1000
FREQUENCY (MHz)
PO
WE
R (
dB
m)
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Conclusions
Conclusion 2: Absolute agreement
The induced noise power can be calculated using the values for coupling attenuation
The calculated induced power fits the measured powers for all cables
Michiel Pelt, Nexans Cabling Solutions, Alsembergsestw 2b3, B-1501 Buizingen, Belgium
Conclusions
Errors during correlation
Incident field uniform but not constantGain set-up varies with frequencyCoupling attenuation approached by
envelope curve ...
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