Near-Field Probes

WHO-Moscow Meeting, December 6th, 2005

Experimental Techniques

Related to Electromagnetic Safety

Albert Romann and Niels Kuster

Foundation for Research on Information Technologies in Society

ETH Zurich, Switzerland

© Foundation for Research on Information Technologies in Society

Interaction of Transmitters with the Human Body

MTE

• design (antenna, housing, internal details)

• antenna matching

Current distribution on the antenna

& device

• size / shape

• external objects

(ear, glasses...)

• hand

• position

• H-field coupling

Phantom / Head

Position of the device

• shell, shell thickness

• tissue parameter

• position

SAR



General Absorption Mechansim

• 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



Dependence on Current Distribution & Device Position

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



SAR Dependence on Handset Design Modifications

• 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


Compliance Testing Procedures

Basic Concept

• 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

˛

well defined procedures

˛ rigorous uncertainty assessment


Near-Field Measurement and Scanning Technology

Experimental Tools

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]

[ 1W/kg; Schuderer et al. ]

Temperature

Diode Loaded

E-Field Sensors

Sensor Array

Vector E-Field

Sensors

Optical TD-Field

Sensors

1970 1975 1980 1985 1990 1995 2000 2005



Optimized Dosimetric Probes


Advanced Electromagnetic Probes for Near-Field Evaluations

Probe

Characterization

Incident field

Probe size

Probe material

Field distortion around the probe

Reflections

Boundary effects

Sensor displacement

Probe material

Field distortion inside the probe

Spherical isotropy

Spatial resolution

Spurious coupling

Diode characteristics

Loading of the sensor

Field detection

Line pickup

Probe linearity

Frequency response

© IFH - Laboratory for EMF and Microwave Electronics - ETH Zurich



Field Distortion Around the Probe

(in % of the incident field at the probe tip)

%

80

50

60

40

40

30

20

20

0

10

-20

0

-40

-10

-60

-20 -10 0 10 20 mm



Field Distortion due to the Boundary

(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

d=3mm

5

10

10

5

8

6

4

0

5 0

2

5

0 d=1mm



Boundary Effects (in lossy liquids)

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.



Local Field Distortions Caused by the Substrate

ET3D ER3D

15

10

5

0

-5

-15

E

-10 -5 0 5

45

°

polarized E-field

10 15

90

60

50

80

70

40

30

20

10

0

ε

=1

ε

=2.54



Deviation from Isotropy

(half sphere) classical design optimized design optimized

2.50

2.00

1.50

1.00

0.50

0.00

-0.50

-1.00

-1.50

-2.00

-2.50

φ overall deviation:

±

2 dB

Lossy liquid

Probe

φ

θ

Active dipole

θ overall deviation:

±

0.25 dB



Performance of the Optimized Dosimetric Probes

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



Isotropic H-Field Probe for Free Space Measurements

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


- 100 MHz to 3 GHz

Dynamic Range:

- 0.01 A/m to 2 A/m (at 1 GHz)


-

±

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


Prototypes of Probes Enabling Pseudo-Vector Information

EV2D HV2D


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


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



Example:

H-field over a microstrip hybrid 6dB coupler at 630 MHz

H-field magnitude H-field vector


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)


- size 6 mm


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)


- size 5 mm


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


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


Design

Probe, Electronics & Positioner Robot

optical output cable

DASY DAE unit pyrex glass wafer Ti marks for wafer sewing probe with microstrip lines glass tip


In Vitro Exposure Analysis

FDTD Analysis: SAR & T - Distribution (SEMCAD)

SAR T(t) t

0.1s

9dB/mm

0.5s

1s

10s

10min

linear scale, arbitrary normalization


In Vitro Exposure Analysis

Measurements & Comparison




• R&D and Production Line Testing



• array of 16 x 8 x Y-X sensors (grid step: 15 mm)








State-of-the-Art and Future Near-Field Evaluation and Design Tools

Other R&D Needs

• calibration methods

• data acquisition

• post processing

• mechanical scanners/positioner

• uncertainty analysis


Calibration Procedure


1. linearization of the dynamic response

2. linearization of the frequency response

3. determination of the sensitivity factors of the different sensors in the different liquids or media

4. determination of the spherical receiving pattern in the different liquids or media (plane patterns are not sufficient!)



Dynamic Range of E-Field 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

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]

not compensated

1.E+02

compensated



Dynamic Range of 3D H-Field Probe

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


Robust Setup for Precise Calibration of Dosimetric E-field Probes

Calibration Procedure for Lossy Liquids

lossy liquid x z y

SARV =

4(Pfw-Pbw) a b

δ cos2(

π y a

)e(-2z/

δ

)

> 3

δ spacer

Pfw Pbw a b



Standing Waves in R9 Waveguide

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



TE01 mode

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


Future Requirements on Dosimetry

DASY4


DASY4: Spatial Peak SAR for Secondary Maxima

standard compliant

spatial peak SAR assessment of 2nd maxima


Overview

Dosimetric Assessment System (DASY4)

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: <

±

0.1dB

• 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

• calibration & verificaton: development of calibration techniques, procedures and setups (e.g., sensitivity, isotropy, spatial resolution, boundary effect, etc.) as well as of verification procedures


Guidelines/Regulations of Compliance Testing of MTE

Guidelines/Regulations for 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)




ES3D E1D


- 30 MHz to 4 GHz

Dynamic Range:

- 0.001 mW/g to 100 mW/g


-

±

0.25 dB




Dimensions:




- 300 MHz to > 10 GHz

Dynamic Range:

- 0.02 mW/g to 100 mW/g


-

±

0.2 dB




Dimensions:





Uncertainty Assessment


Uncertainty Analysis

Steps in Establishing an Uncertainty Budget

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



Measurement System

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 %



Calibration Error

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 %


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 %



Test Sample Related

Test Sample Positioning

Device Holder Uncertainty

Drift of Output Power

Uncertainty

Value

±

6.0 %

±

5.0 %

±

5.0 %


Phantom and Setup

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 %


3 divisior evaluated according to the degree of freedom veff=12

4 divisior evaluated according to the degree of freedom veff=8

5

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 %



Uncertainty Budget for Dosimetric Evaluations with the DASY System

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 %



Uncertainty budget: System Check

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 %



Validation and System

Check

• 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



Conclusions: Near-Field Probes

• 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



Conclusions: Temperature Probes

• 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)



Conclusions: Scanners for Dosimetry/Near-Fields

• 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



Conclusions: Testing Compliance (Basic Restrictions)

• 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



Acknowledgment

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


SEMCAD Simulation Platform

Application: Research and Optimization

LCD holder physical holder floating holder connected

CAD

Measurement Simulation Measurement Simulation



Near-Field Sensors

H3D EF3D HV2D EV2D


Overview

Users of the DASY Technology

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



Isotropic E-Field Probe for Free Space Measurements

ER3D

Spherical Receiving Pattern


- 100 MHz to > 6 GHz

Dynamic Range:

- 2 V/m to > 900 V/m


-

±

0.4 dB


- error at 2.5 mm distance: 5 %


Dimensions:



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



Experimental vs Nurmerical Procedures for

Compliance Testing

• 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


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


Source Modeling (cont.)

edge source excitation




ES3Dmini


- 30 MHz to 6 GHz

Dynamic Range:

- 0.001 mW/g to 100 mW/g


- <

±

0.5 dB




Dimensions:


- dipole offset: 1.0 mm


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.



Performance of the Optimized E-Field Probes

EF3D E1D


- 30 MHz to 5 GHz

Dynamic Range:

- 2 V/m to > 1000 V/m


-

±

0.2 dB



- no error (< 0.1 dB) at: 4.5 mm

Dimensions:




- 300 MHz to 40 GHz

Dynamic Range:

- 10 V/m to > 1000 V/m


-

±

0.2 dB



- no error (< 0.1 dB) at: 2.5 mm

Dimensions:




TD-Sensor

Mechanical fixation of sensor head

AK, March 2005

2 cm

5 cm

500

µ m


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


TD-Sensor

Characterization of the loop sensor

- Characterization in dipole field (835 MHz)

- Calibration with SPEAG H-field probe glass fibers z

y x

loop

scan line dipole

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]


Optical Link RF-Field Sensor

Dipole Test Bench

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


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


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


Data Acquisition System




Data Acquisition Electronics (DAE)

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



DASY 4 Measurement Server

• 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



Data Acquisition Electronics



Characteristics of Data Acquisition Electronics

• 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



Free Space 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



Frequency Response

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



Frequency Range of 3D H-Field Probe

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



SAR Distribution

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



Uncertainty Concept

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



•

•

•

Uncertainty Classes

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.



Device Positioner

• 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



Light Beam Switch for

Probe Tooling

• 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


DASY4

Evaluation According to IEEE1528, IEC62 209, etc.
