WHO-Moscow Meeting, December 6th, 2005
Albert Romann and Niels Kuster
Foundation for Research on Information Technologies in Society
ETH Zurich, Switzerland
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Interaction of Transmitters with the Human Body
• design (antenna, housing, internal details)
• antenna matching
• position
• H-field coupling
• shell, shell thickness
• tissue parameter
• position
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Interaction of Transmitters with the Human Body
• the currents are predominantly induced in the tissues by inductive coupling, i.e., they are mainly proportional to the magnetic field distribution at the skin of the user
4
• main parameters determining SAR levels in the near-field:
~ H 2 (H = magnetic field strength at the skin)
~ j 2 (j = current density on antenna/enclosure)
~ 1/d
2
(d = distance between tissue and antenna/enclosure)
~
σ
(
σ
= conductivity of the tissue)
~ f (f = frequency)
• reactive magnetic field components couple as efficiently as the radiating components
˛ strong dependence of SAR on device position with respect to head
˛ strong dependence of SAR values on handset design
˛ dependence of SAR on scatterer
4Kuster et.al., IEEE Trans. on VT, Vol. 41, No.1 February 1992, pp. 17-23
© Foundation for Research on Information Technologies in Society
Interaction of Transmitters with the Human Body
j antenna j enclosure a touch current distribution on the antenna ( j antenna )
• concentrated on the antenna
• magnitude depends on antenna impedance current distribution on the enclosure ( j enclosure )
• distribution and magnitude depends on design and internal structures
• zero to as high as antenna current
100
°
SAR
SAR(j enclosure
)
SAR(j antenna ) touch 80
°
90
°
100
°
110
° a
© Foundation for Research on Information Technologies in Society
Interaction of Transmitters with the Human Body
• antenna
• current distribution on the device
• driving point impedance/matching network
• secondary RF current paths/parasitic coupling
• power dissipation
˛ performance can strongly depend on various mechanical details not obviously linked to RF performance
˛ components may be changed during production and therefore routine evaluation of the RF performance should be part of any QA program, especially the spatial peak SAR, due to the possibly important legal implications
© Foundation for Research on Information Technologies in Society
Compliance Testing Procedures
• definition/implementation of an open methodology which does not underestimate the user’s exposure for the large majority of the user population neither overestimates exposure by a large extent
˛ conservative phantom (90 percentile), i.e., shap/tissue composition
• the assessment should be unbiased with respect to the phone design, i.e., high exposure in real life should result in high exposure in the test independent of the specific design and vice versa.
˛ well defined standardized anthropometric phantom and actual device positions
• high interlaboratory repeatability of the assessed spatial peak SAR values with minimal uncertainty
˛ optimized components with respect to accuracy
˛
˛ rigorous uncertainty assessment
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
100 cm 3
10 cm 3
[ 1E-9 W/kg; Meier et al. ]
[ 1E-5 W/kg; Heinzelmann et al. ]
1 cm 3
[ 1E-1
[ 0.001 W/kg; Pokovic et al. ]
0.1 cm 3
0.01 cm 3
A/m
1 mm 3
0.1 mm 3
[ 50W/kg; Opt T-Sensors]
Temperature
Diode Loaded
E-Field Sensors
Sensor Array
Vector E-Field
Sensors
Optical TD-Field
Sensors
1970 1975 1980 1985 1990 1995 2000 2005
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
© Foundation for Research on Information Technologies in Society
Advanced Electromagnetic Probes for Near-Field Evaluations
Incident field
Probe size
Field distortion around the probe
Sensor displacement
Field distortion inside the probe
Spurious coupling
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Near-Field Measurement and Scanning Technology
Advanced Electromagnetic Probes for Near-Field Evaluations
(in % of the incident field at the probe tip)
%
80
50
60
40
40
30
20
20
0
10
-20
0
-40
-10
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
(in % of the frontal incident plane wave at 900 MHz at the probe tip)
20
%
18
25
25
20
15
20
15
16
14
12
10
5
0
5 0
5
10
10
5
8
6
4
0
5 0
2
5
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
35 1.8
z z track of the electric probe
1.6
track of the electric probe
30
ET1D
1.4
source
25 WG
ES3D
1.2
20 ET3D
1.0
15
0.8
0.6
10
5
0.4
0 5 10 15 z [mm]
20 25 30
0
0
S=S
0
+S
5 b
10 z[mm]
exp (- z
15
π
20 z )
Compensation works well as long as:
• the boundary curvature is small;
• the probe is angled less than 30
°
to the boundary;
• the distance between the probe and boundary
is larger than 25% of the probe diameter;
• the probe is symmetric.
The described compensation technique enables the reduction of boundary effect error to
<3% for compliance testing with DASY3.
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
ET3D ER3D
90
60
50
80
70
40
ε
=1
ε
=2.54
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
(half sphere) classical design optimized design optimized
2.50
φ overall deviation:
±
2 dB
Probe
φ
θ
Active dipole
θ overall deviation:
±
0.25 dB
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Near-Field Measurement and Scanning Technology
Spherical Receiving Pattern
Frequency Range:
- 30 MHz to 5 GHz
Dynamic Range:
- 0.001 mW/g to 100 mW/g
Spherical Isotropy:
- <
±
0.3 dB
Boundary Effect:
- error at 1 mm distance: 6 %
- no error (< 0.1 dB) at: 4 mm
Dimensions:
- dipole length: 3.0 mm
- dipole offset: 2.0 mm
- tip diameter: 3.9 mm (incl. cover)
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
φ θ
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
1.2
H3D
1.1
modified
PEEK tip
1.0
0.9
0.8
0.7
0.6
0 500 1000 1500 f [MHz]
2000 standard
PEEK tip
2500 3000
Frequency Range:
- 100 MHz to 3 GHz
Dynamic Range:
- 0.01 A/m to 2 A/m (at 1 GHz)
Spherical Isotropy:
-
±
0.2 dB
Dimensions:
- loop diameter: 3.8 mm
- tip diameter: 6.0 mm
E-field Sensitivity:
- at 2.5 GHz: <5% (<10% standard PEEK tip)
- at 3.0 GHz: 7% (15% standard PEEK tip)
© Schmid & Partner Engineering AG, Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
Prototypes of Probes Enabling Pseudo-Vector Information
EV2D HV2D
Frequency Range:
300 MHz to > 6 GHz
Dynamic Range:
2 V/m to > 1 kV/m
Isotropy:
- spherical: <
±
0.17 dB
Dimensions:
- dipole length: 3 mm
- tip diameter: 4 mm
Frequency Range:
300 MHz to 3 GHz
Dynamic Range:
0.03 A/m to 2 A/m (at 900 MHz)
Isotropy:
- spherical: <
±
0.2 dB
Dimensions:
- loop diameter: 3 mm
- tip diameter: 4 mm
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Advanced Electromagnetic Probes for Near-Field Evaluations
H-field over a microstrip hybrid 6dB coupler at 630 MHz
H-field magnitude H-field vector
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Time-Domain Sens
State-of-the-Art Electrooptic Sensors
Mach-Zehnder-Interferometer
National Physics Laboratory (UK) & Tokin Corp. (Japan)
(B. Loader, W. Liang, S. Torihata, 2001)
Prototype development: (isotropic)
11 cm
- bandwidth DC - 1 GHz
- sensitivity 10 µV/m
- dyn. range 150 dB
- size 11 cm
6 mm
- bandwidth DC - 1 GHz
- sensitivity 15 mV/m (@ 30 Hz)
- dyn. range 120 dB
- size 6 mm
© Foundation for Research on Information Technologies in Society
Time-Domain Senso
Modulated Light Source (VCSEL laser)
Technical University of Berlin (Germany)
Mann and Petermann (2002)
“ VCSEL-based miniaturised E-field probe with high sensitivity and optical power supply”
Development for hyperthermia applications (therefore demonstrated bandwidth only 100 MHz), remote powering of the laser with a photovoltaic cell.
- bandwidth DC - 100 MHz (not limit)
- sensitivity 50 µV/ (m√Hz)
- dyn. range 130 dB
- size 5 mm
© Foundation for Research on Information Technologies in Society
TD-Sensor
Fiber-optic link concept
New outstanding features:
- electrical isolation
- miniature size (2 mm) minimal field disturbance
- large frequency range (0.1-6 GHz)
- amplitude and frequency information
- high spatial resolution
Challenges:
- low power consumption
- miniature size (mm dimensions)
- broadband response
AK, March 2005 antenna ampl.
* f pv array laser diode on chip optical fibers remote unit light source photo detector data processing unit
© Foundation for Research on Information Technologies in Society
TD-Sensor
Sensor head
Circuit diagram
Amplifier
R
1
Bias
RF in laser
C
1
PVC
AK, March 2005
Miniature size: 1.25 mm x 2 mm
RF in
PVC
R
Amplifier
C
500
µ m
© Foundation for Research on Information Technologies in Society
Design
optical output cable
DASY DAE unit pyrex glass wafer Ti marks for wafer sewing probe with microstrip lines glass tip
© Foundation for Research on Information Technologies in Society
In Vitro Exposure Analysis
SAR T(t) t
0.1s
9dB/mm
0.5s
1s
10s
10min
linear scale, arbitrary normalization
© Foundation for Research on Information Technologies in Society
In Vitro Exposure Analysis
© Foundation for Research on Information Technologies in Society
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
• R&D and Production Line Testing
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
• array of 16 x 8 x Y-X sensors (grid step: 15 mm)
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
© Foundation for Research on Information Technologies in Society
State-of-the-Art and Future Near-Field Evaluation and Design Tools
• post processing
• mechanical scanners/positioner
© Foundation for Research on Information Technologies in Society
Calibration Procedure
1. linearization of the dynamic response
2. linearization of the frequency response
4. determination of the spherical receiving pattern in the different liquids or media (plane patterns are not sufficient!)
© Schmid & Partner Engineering AG, Zurich
Calibration Procedure
1.E+7
1.E+6
1.E+5
1.E+4
1.E+3
1.E+2
1.E+1
1.E+0
1E-04 1E-03 1E-02 1E-01
[mW/g]
1E+00 1E+01 1E+02
-1
-2
1
0
-3
1.E-04 relative accuracy compensated not compensated diode characteristic
1.E-02 1.E+00
[mW/g]
1.E+02
© Schmid & Partner Engineering AG, Zurich
Calibration Procedure
1.E+6
1.E+5
1.E+4
1.E+3
1.E+2
1.E+1
1.E+0
1E-03 1E-02 1E-01
[A/m] (at 900MHz)
1E+00 1E+01
1
0
-1
-2
-3
1E-02 compensated relative accuracy not compensated diode characteristic
1E-01 1E+00
[A/m] (at 900MHz) not compensated compensated
1E+01
© Schmid & Partner Engineering AG, Zurich
Robust Setup for Precise Calibration of Dosimetric E-field Probes
SARV =
4(Pfw-Pbw) a b
δ cos2(
π y a
)e(-2z/
δ
)
© Schmid & Partner Engineering AG, Zurich
Robust Setup for Precise Calibration of Dosimetric E-field Probes
10cm H2O, open WG
10cm H2O, shorten WG
12cm H2O, open WG
12cm H2O, shorten WG
10cm Brain, open&shorten WG lossy liquid x z y dielectric slab
Pfw Pbw
> 3
δ
50mm a b
© Schmid & Partner Engineering AG, Zurich
Robust Setup for Precise Calibration of Dosimetric E-field Probes
R9 Waveguide R22 Waveguide
E [V/m]
35
30
25
20
15
10
5 x z y
E [V/m]
55
25
15
45
35
5
© Schmid & Partner Engineering AG, Zurich
Future Requirements on Dosimetry
© Foundation for Research on Information Technologies in Society
standard compliant
spatial peak SAR assessment of 2nd maxima
© Foundation for Research on Information Technologies in Society
Overview
Research Achievements
• novel probes: sensitvity: <±1 µ W/kg; spherical isotropy: <±0.3dB; linearity: <±0.2dB; boundary effect:
<0.1dB at 4mm; immunity against secondary modes of reception: <±0.1dB
• probe positioning: surface detector: <
±
0.2mm; positioner: <
±
0.1mm; wobbling: <
±
0.1mm; rotation precision: <
±
0.5
°
• data acquisition: amplification & filtering: <
• new algorithms: extrapolation: <
±
0.15dB; cube searchand interpolation: <
±
0.15dB
• phantoms: provision of scientific data & rationale, development of phantoms & liquids
• test position: provision of scientific data & rationale for test position, development of holder
© Foundation for Research on Information Technologies in Society
Guidelines/Regulations of Compliance Testing of MTE
1982
1992
1992
1992
1992
1993
1995
1996
1997
1998
Safety Guidelines: ANSI/IEEE C95.1 (7-Watt Exclusion)
Publication of Interaction Mechanism (IEEE Trans VT-41)
Safety Guidelines: ANSI/IEEE C95.1 (revised exclusion clause)
Call: German Agency for Radiation Protection
Mandate: R&D of Compliance Procedure (MPT,D; Telekom,D...)
Safety Guidelines: RCR Std-38 (J)
Safety Guidelines: CENELEC prENV50166-1 (withdrawn 1998)
Call: ICNIRP (mobile communications)
Order: FCC USA (based on NRPB 1996/ANSI92)
Recommendation: ARIB Std-T56 (J)
1998
1998
1998
1999
1999
2001
Safety Guidelines: ICNIRP
Specifications: ES59005 (CENELEC TC211B WGMTE 95-98)
Order: Australia Certification Standard (Revision 4.0)
Harmonization Group: IEEE, CENELEC, ARIB, CHINA
Order: R&TTE EU Directive (law: April 8, 2000, transition: 1 year)
Standard: EN50360/50361 (TC211 MBS 98-00; ratified July 01)
2001 Order: Japanese Gov. (summer 01; transition: 1 year)
200 3 Standard: IEEE Std 1528-200 3 (SCC34-SC2 WG1 97-0 3 )
200X Standard: IEC TC106 (based on CENELEC, scheduled: 01)
© Foundation for Research on Information Technologies in Society
Advanced Electromagnetic Probes for Near-Field Evaluations
ES3D E1D
Frequency Range:
- 30 MHz to 4 GHz
Dynamic Range:
- 0.001 mW/g to 100 mW/g
Spherical Isotropy:
-
±
0.25 dB
Boundary Effect:
- error at 1 mm distance: 6 %
- no error (< 0.1 dB) at: 4 mm
- tip diameter: 3.9 mm (incl. cover)
Frequency Range:
- 300 MHz to > 10 GHz
Dynamic Range:
- 0.02 mW/g to 100 mW/g
Spherical Isotropy:
-
±
0.2 dB
Boundary Effect:
- error at 1 mm distance: 0 %
- no error (< 0.1 dB) at: 1 mm
© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich
Near-Field Measurement and Scanning Technology
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
1
• Assign a probability distribution and determine the standard uncertainty of each distribution.
Normal Distribution: u(xi) = uncertainty k
Rectangular Distribution: u(xi) = a i
3
U-Shaped Distribution: u(xi) =
M
2
• Determine the combined standard uncertainty.
u c
(y) =
Σ u 2 (x i
)
• Determine the expanded uncertainty. U = k u c
(y)
The level of confidence recommended by NIST for EMC testing is 95% which can be obtained with k=2.
1
NIST Technical Note TN 1297, http://physics.nist.gov/Pubs/guidelines/TN1297/tn1297s.pdf
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
Calibration
Axial isotropy
Hemispherical isotropy
Spatial resolution
Boundary effect
Linearity
Detection Limit
Readout Electronics
Response Time
Integration Time
Mechanical Constrains of Robot
Probe positioning
Extrapolation/Integration
Uncertainty
Value
±
4.4 %
±
4.7 %
±
9.6 %
±
0.0 %
±
5.5 %
±
4.7 %
±
1.0 %
±
1.0 %
±
0.8 %
±
1.4 %
±
0.4 %
±
2.9 %
±
3.9 %
Combined Standard Uncertainty
Probability
Distribution normal rectangular rectangular rectangular rectangular rectangular rectangular normal rectangular rectangular rectangular rectangular rectangular
RSS
1
√
3
√
3
√
3
√
3
√
3
√
3
1
√
3
√
3
√
3
√
3
√
3
Divisor c
1
1
1 i
1
(1-c p
)
1/2
1
1
1
1
1
1
√ c p
1
Standard
Uncertainty
±
4.4 %
±
1.9 %
±
3.9 %
±
0.0 %
±
3.2 %
±
2.7 %
±
0.6 %
±
1.0 %
±
0.5 %
±
0.8 %
±
0.2 %
±
1.7 %
±
2.3 %
±
8.1 %
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
Incident power
Mismatch
Liquid conductivity
Probe positioning
Probe linearity
Field Homogeneity
Uncertainty
Value
±
4.5 %
±
1.0 %
±
2.6 %
±
1.0 %
±
4.7 %
±
2.4 %
Combined Standard Uncertainty
Probability
Distribution rectangular rectangular rectangular normal rectangular rectangular
RSS
Divisor
√
3
√
3
√
3
1
√
3
√
3 c i
1
1
1
1
1
1
Standard
Uncertainty
±
2.6 %
±
0.6 %
±
1.5 %
±
1.0 %
±
2.7 %
±
1.4 %
±
4.4 %
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
Test Sample Positioning
Device Holder Uncertainty
Drift of Output Power
Uncertainty
Value
±
6.0 %
±
5.0 %
±
5.0 %
Combined Standard Uncertainty
Phantom Uncertainty
Liquid Conductivity (target)
Liquid Conductivity (meas.)
Liquid Permittivity (target)
Liquid Permittivity (meas.)
RF Ambient Conditions
Uncertainty
Value
±
4.0 %
±
5.0 %
±
10 %
±
5.0 %
±
5.0 %
±
3.0 %
Combined Standard Uncertainty
3 divisior evaluated according to the degree of freedom veff=12
4 divisior evaluated according to the degree of freedom veff=8
0.5 is the largest sensitivity for 10g average (0.6 for 1g average)
Probability
Distribution normal normal rectangular
RSS
Probability
Distribution rectangular rectangular rectangular rectangular rectangular rectangular
RSS
Divisor
0.89
3
0.84
4
√
3 c i
1
1
1
Standard
Uncertainty
±
6.7 %
±
5.9 %
±
2.9 %
±
9.4
Divisor
√
√
√
√
√
√
3
3
3
3
3
3 c i
Standard
(10-g) Uncertainty
1
0.5
0.5
0.5
0.5
1
5
±
2.3 %
±
1.4 %
±
2.9 %
±
1.4 %
±
1.4 %
±
1.7 %
±
4.8 %
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
Uncertainty
Value
Probability
Distribution
Measurement System
Test sample Related
Phantom and Setup
Combined Uncertainty
Expanded Uncertainty (k=2)
RSS
RSS
RSS
Standard
Uncertainty
(1-g)
±
8.1 %
±
9.4 %
±
5.4 %
Standard
Uncertainty
(10-g)
±
8.1 %
±
9.4 %
±
4.8 %
±
13.5 %
±
13.3 %
±
27.1 %
±
26.6 %
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
Calibration
Axial isotropy
Hemispherical isotropy
Boundary effect
Linearity
Detection Limit
Readout Electronics
Response Time
Integration Time
Mechanical Constrains of Robot
Probe positioning
Extrapolation/Integration
Dipole/Liquid Distance
Dipole Input Power
Liquid conductivity (target)
Liquid conductivity (meas.)
Liquid permittivity (target)
Liquid permittivity (meas.)
RF Ambient condition
Uncertainty Probability
Value Distribution
±
4.4 %
±
4.7 % normal rectangular
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
9.6 %
5.5 %
4.7 %
1.0 %
1.0 %
0.0 %
0.4 %
0.4 %
2.9 %
3.9 %
1.0 %
4.7 %
5.0 %
10 %
5.0 %
5.0 %
3.0 % rectangular rectangular rectangular rectangular normal rectangular rectangular rectangular rectangular rectangular rectangular rectangular rectangular rectangular rectangular rectangular rectangular
Divisor
1
1
1
1
0
1
1 c i
1-g
1
1
1
√
3
1
√
√
√
√
√
√
3
3
3
3
3
3
√
√
√
√
3
3
3
3
√
3
√
3
√
3
√
3
√
3
√
3
1
1
1
1
1
0.6
0.6
0.6
0.6
1
Combined Standard Uncertainty RSS c i
Standard
10-g Unc. (1g)
1
1
±
4.4 %
±
2.7 %
1
1
1
1
0
1
1
±
0.0 %
±
3.2%
±
2.7 %
±
0.6 %
±
1.0 %
±
0.0 %
±
0.2 %
1
1
1
±
0.2 %
±
1.7 %
±
2.3 %
±
0.6 % 1
1
±
2.7 %
0.5
±
1.7 %
0.5
±
3.5 %
0.5
±
1.7 %
0.5
±
1.7 %
1
±
1.7 %
±
9.5 %
Standard
Unc. (10g)
±
4.4 %
±
2.7 %
±
0.0 %
±
3.2 %
±
2.7 %
±
0.6 %
±
1.0 %
±
0.0 %
±
0.2 %
±
0.2 %
±
1.7 %
±
2.3 %
±
0.6 %
±
2.7 %
±
1.4 %
±
2.9 %
±
1.4 %
±
1.4 %
±
1.7 %
±
9.2 %
© Schmid & Partner Engineering AG, Zurich
Near-Field Measurement and Scanning Technology
• Enables verification that the system is performing according to specifications
• Problems which are detected:
- inappropriate liquid
- malfunction of probe
- malfunction of surface detector
- evaluation problems matched dipole
(at phantom) spatial peak SAR vs input power specified distance holder
© Schmid & Partner Engineering AG, Zurich
State-of-the-Art and Future Near-Field Evaluation and Design Tools
• Diode-loaded probes have been optimized during the last decade; close to physical limits
• Breakthroughs are expected in active sensors
• System prices for TD-Sensors will be higher since spectrum analyzer or equivalent will be required
• Current and expected specifications of E- and H-field probes with spatial resolutions of better than 0.1cm
3
are:
Parameters Diode Loaded Sensors TD-Sensors
- information: amplitude; broad-band [future: time domain; phase; polarization (pseudo v-probe) narrow-band; full vector]
- sensitivity: 1 V/m; 10 mA/m@1GHz
- frequency range: E: 0.01-50GHz; H:0.1-3GHz
[future: <0.01 V/m; <0.01 mA/m]
[future: similar]
- dynamic range: 40dB
- spherical isotropy: <0.3 dB
[future: 80 dB]
[future: <0.3dB]
- spatial resolution: < 30 mm
3
; 1mm
3
(special cases) [future: < 1 mm
3
]
-> Probe performance meets the needs of any dosimetric assessments
(compliance testing & bioexperiments); The needs for near-field evaluations are not satisfied yet
© Foundation for Research on Information Technologies in Society
State-of-the-Art and Future Near-Field Evaluation and Design Tools
• The best test equipments today enable temperature measurements in hostile environments with the following specifications:
- temperature range: 0 - 60
°
C [future: 0 - 100
°
C]
- sensitivity: < 1mK [future: < 5mK]
- spatial resolution: <1mg
- time constant: approx. 1s
[future: <0.001 mg]
[future: approx. 0.14ms]
-> The precision and spatial resolution is sufficient to determine and localize thermal hotspots (e.g., in bioexperiments)
© Foundation for Research on Information Technologies in Society
State-of-the-Art and Future Near-Field Evaluation and Design Tools
• The best test equipments today enable dosimetric measurements with a precision of better than 1 dB:
- frequency range: 30 MHz - 6 GHz
- linearity : <0.2 dB for TDMA
[future: up to 10 GHz]
[future: <0.2dB for any mod.]
- sensitivity:
- dynamic range:
1mW/kg or better
40dB
- spatial resolution: <10mg (routine)
1mg (special cases)
[future: <0.01 mW/kg]
[future: 80 dB]
[future: <0.1 mW/kg]
• The precision is sufficient to determine spatial peak SAR on any mass or volume [future: contiguous tissue]
• Array scanners are accurate and conduct a flat phantom scan in <3s
[future: various shapes; 3D-arrays]
• Due to the complexity of the equipment, excellent scientific and engineering knowledge is required to develop and manufacture a system.
-> The future demands more features and faster assessments; the
needs of spatial resolution and accuracy are largely met
© Foundation for Research on Information Technologies in Society
State-of-the-Art and Future Near-Field Evaluation and Design Tools
• internationally recommended procedures warrant conservative estimations of the maximum human exposure (1g & 10g)
• uncertainty: <25% (best equipment only)
• interlaboratory repeatability : <15%
• total laboratory costs for compliance testing: ~ US$250k
© Foundation for Research on Information Technologies in Society
State-of-the-Art and Future Near-Field Evaluation and Design Tools
Advice
Q. Balzano, Howard Bassen, Lars Bomholt, Kwok Chan, Camelia Gabriel,
Luc Martens, Toshio Nojima, Katja Pokovic, Yahya Rahmat-Samii, Theodore
Samaras, Thomas Schmid, Masao Taki
Support
• Swiss Commission for Technology and Innovation
• European Union
• MMF, Belgium
• MOTOROLA, USA
• NOKIA, Finland
• Ericsson, Sweden
• T-MOBIL, Germany
• ARIB, Japan
• TDC SUNRISE, Switzerland
• SWISSCOM, Switzerland
• SPEAG, Switzerland
© Foundation for Research on Information Technologies in Society
SEMCAD Simulation Platform
LCD holder physical holder floating holder connected
CAD
Measurement Simulation Measurement Simulation
© Foundation for Research on Information Technologies in Society
Advanced Electromagnetic Probes for Near-Field Evaluations
H3D EF3D HV2D EV2D
© Schmid & Partner Engineering AG, Zurich
Overview
Governments
Chinese Center for Disease Control CN
Federal Communications Commission US
South African Bureau of Standards
Radio Research Laboratory
SA
KR
Communications Research Laboratory JP
Radio Equip. Inspection&Certification Inst.
BSMI
JP
TW
Telecommunication Metrology Center CN
DG TTI ES
Radiation and Nuclear Safety Authority FI
Manufacturers & Providers
Ace Technology Corp. KR
Acer Communications & Multimedia Inc. TW
ADT
Alcatel Business Systems
Amphenol
Amphenol T&M Antennas, Inc.
A-pex
Appeal Telecom Co. Ltd.
Auden
Avantego
Casio
Centurion International Inc.
TW
F
KR
US
Cetecom ICT Services GmbH
Compal
Digital EMC
Doshisya
Fujitsu
Galtronics
Globus Cellular Ltd.
KR
JP
JP global
CAN
JP
KR
TW
SE
JP
US
D
TW
Hanwah Corp. / Telecom
HTC
Hyundai Electr. Ind. Co.
JQA
Kenwood
Kyocera Wireless Copr.
Kyusuyu
LG Electronics Inc.
LK Products Oy
Matsushita Communications
MCI
Meerae Tech
MEI
MEL
Moteco
Motorola (>5)
Murata
NEC
Nokia Mobile Phones (> 5)
NTT DoCoMo
Philips Consumer Communication
PSB Corporation Pte Ltd.
Qualcomm Inc.
Quanta
Radio Frequency Investigation Ltd.
Samsung Electronics Co. Ltd. (> 5)
Sanyo China
SB Telcom Co. Ltd.
Sewon
Siemens AG
Siemens AG
SK Teletech Co. Ltd.
Sony
Sony Ericsson (> 5)
JP
JP global
JP
F
SG
US
TW
UK
KR
Asia
KR
KR
DE
DK
KR
JP global
SF
GB
JP
KR
JP
JP global global
KR
TW
KR
JP
JP
JP
JP
KR
Stock
TDK Group Co.
Telson Electronics Co. Ltd.
T-Nova (former Deutsche Telekom)
Toshiba
Tsuyama
Xellant Inc.
JP global
KR
D
JP
JP
IL
Universities & Test Labs
Intertek Testing Services NA Inc.
National University Singapore
PCTest Engineering Laboratory Inc.
Underwriters Laboratories Inc.
US
SG
US
US
EMC Technologies
National Com. University
Universidad Politecnica de Cartagena SP
ETS Dr. Genz GmbH
Compliance Certification Services
AS
JP
D
US
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
ER3D
Spherical Receiving Pattern
Frequency Range:
- 100 MHz to > 6 GHz
Dynamic Range:
- 2 V/m to > 900 V/m
Spherical Isotropy:
-
±
0.4 dB
Boundary Effect:
- error at 2.5 mm distance: 5 %
- no error (< 0.1 dB) at: 6 mm
Dimensions:
- dipole length: 3.0 mm
- tip diameter: 8.0 mm (incl. cover)
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
0
40
80
120
160
φ 200
240
280
320
0
20
40
60
80
100
120
θ
140
160
© Schmid & Partner Engineering AG, Zurich
Interaction of Transmitters with the Human Body
• spatial peak SAR values of current handsets are close to the safety limits
• SAR is strongly dependend on various electrical and mechanical details not obviously linked to RF performance
• SAR may strongly dependent on internal substructures of the device
˛ compliance can only be demonstrated by experimental means
˛ simulations cannot be alternative for compliance testing but for product development
© Foundation for Research on Information Technologies in Society
IPEM - Glasgow, Septeber 7th, 2005
•
Experimental EMF Exposure Assessments assessment of the EMF induced in biological tissues or bodies
-> exact distribution: numerical techniques, validation for complex transmitters
-> compliance: experimental in conservative phantoms
• assessment of the incident EMF
- near-field and standing wave
-> compliance: E- and H-field distribution (3D) with a spatial resolution of much smaller than wavelength
- quasi plane-wave conditions (angle of incident, field impedance)
-> compliance: maximum E-field in a plane
© Foundation for Research on Information Technologies in Society
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
Frequency Range:
- 30 MHz to 6 GHz
Dynamic Range:
- 0.001 mW/g to 100 mW/g
Spherical Isotropy:
- <
±
0.5 dB
Boundary Effect:
- error at 1 mm distance: 3 %
- no error (< 0.1 dB) at: 2 mm
Dimensions:
- dipole length: 2.8 mm
- dipole offset: 1.0 mm
- tip diameter: 2.5 mm (incl. cover)
Dynamic Range of ES3Dmini Probe
1.E+7
1.E+6
1.E+5
1.E+4
1.E+3
1.E+2
1.E+1
1.E+0
0.0001
0.001
0.01
0.1
mW/cm
3 not compensated
1.
10.
compensated
100.
© Foundation for Research on Information Technologies in Society
Near-Field Measurement and Scanning Technology
EF3D E1D
Frequency Range:
- 30 MHz to 5 GHz
Dynamic Range:
- 2 V/m to > 1000 V/m
Spherical Isotropy:
-
±
0.2 dB
Boundary Effect:
- error at 2.5 mm distance: 3 %
- no error (< 0.1 dB) at: 4.5 mm
Dimensions:
- dipole length: 2.8 mm
- tip diameter: 3.9 mm
Frequency Range:
- 300 MHz to 40 GHz
Dynamic Range:
- 10 V/m to > 1000 V/m
Spherical Isotropy:
-
±
0.2 dB
Boundary Effect:
- error at 2.5 mm distance: 1 %
- no error (< 0.1 dB) at: 2.5 mm
Dimensions:
- dipole length: 0.8 mm
- tip diameter: 1.0 mm
© Schmid & Partner Engineering AG, Zurich
TD-Sensor
Mechanical fixation of sensor head
AK, March 2005
2 cm
5 cm
500
µ m
© Foundation for Research on Information Technologies in Society
TD-Sensor
Evaluation of field sensitivity of sensor head a) with short at LNA input b) with loop at LNA input
AK, March 2005
Loop diameter: ¢ = 3.4 mm
LNA package size: 2.0 x 1.25 mm
Loop
R
1
Amplifier
Bias
R
2 laser
C
1
PVC
C
2
© Foundation for Research on Information Technologies in Society
TD-Sensor
Characterization of the loop sensor
- Characterization in dipole field (835 MHz)
- Calibration with SPEAG H-field probe glass fibers z
loop
AK, March 2005
0.8
0.7
0.6
SPEAG H field probe
AOS, 0deg
AOS, 90deg
AOS, 180deg
AOS, -90deg
0.5
0.4
0.3
0.2
0.1
dipole length
0
-125 -100 -75 -50 -25 0 25 50 75 100 125 y [mm]
© Foundation for Research on Information Technologies in Society
Optical Link RF-Field Sensor
NWA
HP8753E
PC (Matlab)
Lab. power supply
DC block data fiber
50/125
New Focus detector power fiber opt. coupler
90%
10% power laser
850nm
FCPC geradschliff
HAC dipol opt. power meter
Dasy 4 system for sensor mounting sensor head
Peter Müller, June 6th, 2005
© Foundation for Research on Information Technologies in Society
TD-Sensor
Characterization of the loop sensor
Output noise and link gain determine min. detectable H-field:
Sensitivity
AK, March 2005
H min
∆ν
=
ρ load g
( )
ν [GHz] 0.835
g [dBm/ (A/m)
2
]
ρ load
[dBm/Hz]
2.55
-16.5 (no loop)
-140.3
H min
nA m
⋅
1
Hz
72
2.45
0.97
-140.4
85
5Mhz BW
@2.45 GHz
0.2 mA/m
ν: frequency
∆ν: bandwidth g: gain
ρ load
: output power noise
H: magnetic field
¢ of loop: 3.4mm
Input light: 50 mW
© Foundation for Research on Information Technologies in Society
TD-Sensor
Dynamic range
AK, March 2005
P out log-log-plot
1dB compression point
Definitions: a) 1dB compression point b) spurious products (harmonics or intermodulation products)
ω
2ω
3ω
ρ noise
∆ν min
P in fundamental
2nd order
3rd order max
P in
P in
SNDR [dB*Hz]
SFDR [dB*Hz
1/2
] (2 ω )
[dB*Hz
2/3
] (3 ω, 2 ω 1 −ω 2 , 2 ω 2 −ω 1 )
ν
Measurement
(with two-tone method, IM3 products)
:
= 0.835 GHz
SNDR [dB*Hz] 135
H max
A m
0.4
95 0.004
SFDR [dB*Hz
2/3
]
H min
nA
⋅ m
1
Hz
72
© Foundation for Research on Information Technologies in Society
Data Acquisition System
© Schmid & Partner Engineering AG, Zurich
Data Acquisition System
Chan. X
Chan. Y x 10 x 10 x 100 x 100
Mux
Sampling
ADC
(16Bit)
Data
Status opt.
trans.
optical
Downlink
Chan. Z x 10
Mechanical Surface Detector
Collision Detector x 100
Logic
Power
Managment opt.
rec.
optical
Uplink on/off
© Schmid & Partner Engineering AG, Zurich
Data Acquisition System
• 166MHz low power Pentium MMX
• 32MB chipdisk and 64MB RAM
• Serial link to DAE4 (with watchdog supervision)
• 16 Bit A/D converter for surface detection system
• Two serial links to robot (one for real-time communication supervised by watchdog)
• Ethernet link to PC (with watchdog supervision)
• Emergency stop relay for robot safety chain
• Two expansion slots for future applications
© Schmid & Partner Engineering AG, Zurich
Data Acquisition System
© Schmid & Partner Engineering AG, Zurich
Data Acquisition System
• offset: 1
µ
V
• bias current: < 50 fA
• dynamic range: 1
µ
V - 300 mV
• input impedance: 200 M
Ω
• mechanical surface and collision detector
• battery operated: > 20 hours
• optical down- and uplink
© Schmid & Partner Engineering AG, Zurich
Calibration Procedure
Signal Generator
Attn.
Power
Amplifier
50 dB
P
1
P
2
LP
Filter
Attn.
Attn.
Attn.
Bidirectional
Coupler
20 dB
Cable a)
Calibrated
Attn.
Probe
Adapter c)
P
3
Load b)
Attn.
Short d)
Probe
Adapter
λ
/4
Load
© Schmid & Partner Engineering AG, Zurich
Calibration Procedure
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
1.5
1.4
1.3
1.2
500
TEM Cell
1000 1500 f [MHz]
R22 Waveguide
2000 2500
R26 Waveguide
3000
© Schmid & Partner Engineering AG, Zurich
Calibration Procedure
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
0 500 1000 f [MHz]
1500
X Y Z
2000 2500
© Schmid & Partner Engineering AG, Zurich
Robust Setup for Precise Calibration of Dosimetric E-field Probes
3.0
2.5
2.0
1.5
1.0
0.5
0
0 analytical temperature measurements
10 20 z(mm)
30 40
3.0
2.5
2.0
1.5
1.0
0.5
0
0 analytical
E-field measurements
10 20 z(mm)
30 40
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
1
• The components of uncertainty may generally be categorized according to the methods used to evaluate them.
Type A Evaluation: based on any valid statistical method for treating data
Type B Evaluation:
Combined Standard
Uncertainty: typically based on scientific judgement using all of the relevant information available represents the estimated standard deviation of the result
Expanded Uncertainty: measure of uncertainty that defines an interval about the measurement result within which the measured value is confidently believed to lie
Coverage Factor: level of confidence recommended by NIST for EMC testing is 95% (k=2)
1
NIST Technical Note TN 1297, http://physics.nist.gov/Pubs/guidelines/TN1297/tn1297s.pdf
© Schmid & Partner Engineering AG, Zurich
Uncertainty Analysis
•
•
•
assessment uncertainty
This is the uncertainty for assessment of the spatial peak SAR value in a given
SAR distribution within a given phantom (e.g., head phantom). The uncertainty must be determined in such a manner that it is valid for all evaluations.
phantom uncertainty
This is the uncertainty of the technical setup (head phantom) with respect to the requirements defined in the standard (either standard phantom or definition of the coverage in percentage of the total user population). The uncertainty of the phantom can be assessed once, such that it is valid for all RF transmitters.
EM source uncertainty
This is the uncertainty of the spatial peak SAR assessed with a particular phone or a numerical representation of the phone compared to the phone produced during mass production. The uncertainty of the position with respect to the phantom can also be considered to be part of the source uncertainty.
© Schmid & Partner Engineering AG, Zurich
Near-Field Measurement and Scanning Technology
• Enables the rotation of the mounted transmitter in spherical coordinates whereby the rotation point is the ear opening
• Easy and accurate device positioning according to: CENELEC, IEEE, etc.
rotation point
© Schmid & Partner Engineering AG, Zurich
Near-Field Measurement and Scanning Technology
• Red LED beam-switch with 0.5 mm beam width
• Mounted on robot socket or table
• Automatic probe tooling in 5 axes
• Allows probe rotations with 0.1 mm position accuracy
• Allows repeatable probe positions after changing probes (even among probes with different dimensions) red beam
© Schmid & Partner Engineering AG, Zurich
DASY4
© Foundation for Research on Information Technologies in Society