Usage of Ansoft/HFSS simulation tool in mobile device developmentJari Jekkonen

2 © 2005 Nokia cost_presentation.ppt / 2005-12-13 / JJ

Content

• Commercial, non-commercial and in-house 3D EM tools used in NOKIA

• Development process of mobile phone

• Simulation goals

• Early verification of EM properties of the device

• Design check / validation

• Timing for simulations

• Sample models

• Discussion

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Commercial, non-commercial and in-house 3D EM tools used in NOKIA• Commercial

• Ansoft/HFSS (FEM)

• CST/MWS (FDTD/FIT)

• Flomerics/EMC/FLO (TLM)

• FEKO (MoM/FEM)

• IE3D (MoM)

• Non-commercial• NEC (MoM)

• In-house• Aplac – FDTD

• Boundary-element method by HUT

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Current status of the usage of the HFSS in NOKIA• NOKIA wide EMC simulations network

• Re-use of simulation models (model library)

• Early verification by simulations • started in some sites

• Part of the minimum block design process

• Iterative between mechanics, BB, RF and EMC

• NOKIA wide tool for EM simulations• Import:

• SAT

• STEP

• IGES

• AutoCAD DXF

• SLD

• GEO

• STL

• Export• SAT

• JPEG

• GIF

• BMP

• TIFF

• 3D modeller

• AutoCAD DXF

• VRML

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Development process of the mobile phone

• General steps of the mobile phone development

• M-steps are the maturity check points of the phone development (technology maturity)

are prototype builds

• E-steps are the execution points of product program (management level)

E-1 E0 E0.5 E1 E1.5 E5E2 E3 E4

Pre-study / technology freezePre-study / technology freezeTechnology implementationTechnology implementation

productionproduction

P1 P2 P3 P4 P5 P6

M0 M2 M3 M4 M5 M6 M7M1 M8 M9 M10 M11 M12

SaleSale

Product maturity steps

Project execution milestones

Product builds

P_

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Early verification of EM properties of the deviceGoals are

• to increase EM quality of the product

• to have less HW prototyping during the development project

-> Shorten design time

• Reduce testing time

• to produce design rules for following projects

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Early verification of EM properties of the device• IOP simulations

• Antenna simulations• prototyping

• EM separation of antennas

• Noise coupling between BB parts and antennas• E.g. Camera noise to GSM antenna

• Hinge simulations• Conductive vs. non-conductive

• Surface material effects

• Optimum placement for sensitive components• SIM

• MMC, SD, etc.

• Risk level estimation based on simulations• Done already for couple of projects

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Isolation between GSM antenna and SIM lines

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Isolation between GSM antenna and display

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Design check / validation

• EMC measurements vs. simulations• Model updates

• Re-use blocks to simulations library

• Shielding modifications• E.g. SIM reader is designed by simulations for Gromit

• IOP measurements vs. simulations• Antenna measurements vs. simulations

• Design updates

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Timing for simulations

E-1 E0 E0.5 E1 E1.5 E5E2 E3 E4

Pre-study / technology freezePre-study / technology freezeTechnology implementationTechnology implementation

productionproduction

B1 B2 B3 B4 B5 B6

M0 M2 M3 M4 M5 M6 M7M1 M8 M9 M10 M11 M12

Pre-concept simulation

Detection of potential EMC risks in whole concept and development

of general simulation

plan.

HFSS

Concept simulations

Check for placement of main blocks (antenna,

battery, SIM, MMC, camera,

RF)

HFSS

First test

Draft test of coupling

between parts and antenna (model from other project

is used)

HFSS

Calculation of the near-field radiation and

detection of hot spots on PWB

Second test of coupling

between parts and antenna

HFSS, SIWave

Verification with available proto

EMC checks based on calculation of 3-D

analysis of the EM field inside the product

HFSS, SIWave

SaleSale

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Pre-concept model

• Not very detailed model

• First draft for antenna solution

• Structural resonances

• Best places for sensitive modules/components

concept level model

• More details

• Some component/module locations are fixed

• Simulations for design help

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concept level model

Camera

Grounding points• More details

• Some component/module locations are fixed

• Simulations for design rules

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E-field 900MHz (GSM)

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E-field 1750MHz (GSM)

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E-field 1900MHz (GSM)

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E-field 1980MHz (WCDMA)

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First tests

• Detailed models for EM-parts (connectors, memory card readers, etc.)

• Working antenna model

• All shields and other conductive parts fixed

• Firs EMC tests done and compared to simulations

• Corrections for design (using simulations)

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E & H-field 900MHz (GSM)

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E & H-field 900MHz (GSM)

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E & H-field 1750MHz (GSM)

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E & H-field 1750MHz (GSM)

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E & H-field 1900MHz (GSM)

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E & H-field 1900MHz (GSM)

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E & H-field 1980MHz (WCDMA)

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GSM900 (ver. 1)

Very critical area!

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GSM1800 (ver. 1)

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GSM1900 (ver. 1)

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GSM900 (ver. 2)

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GSM1800 (ver. 2)

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GSM1900 (ver. 2)

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Conclusions

Simulation• tools are very useful from the very beginning of the design

process• can be used as a risk analysis tool of the EM environment of the

product• can be used to make prototyping with limitations• may be used to produce design rules for daily engineering work

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Questions?