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FEKO내전자기해석솔버의올바른선택법

2018.04.17.

Copyright © 2018 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.

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발표내용

• FEKO 소개

• FEKO의시뮬레이션맵과주파수의연관성

• 다양한응용예에따른적정솔버의적용방법

• Antenna Design (안테나 설계)

• Antenna Placement (안테나위치선정)

• Electromagnetic Compability (EMC)

• Scattering / RCS

• 기타응용 (waveguides, microstrip circuits and bio-electromagnetics)

• 정리


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Introducing FEKO

Electromagnetic

simulation

Altair FEKO is a leading comprehensive

electromagnetic (EM) analysis software

suite, widely used in many industries and

built on state of the art computational EM

(CEM) techniques, to provide users with

software that can solve a broad range of

electromagnetic problems.


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FEKO Key Applications

Electromagnetic

Compatibility (EMC)

Multiphysics Analysis and Optimization

Antenna Design Others ScatteringAntenna Placement


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FEKO UI Components – CADFEKO and Solver

• CADFEKO: Model creation / import, definition, simulation and output specification

• Solver: Performs calculations

CADFEKO

POSTFEKO

FEKO Solver


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FEKO UI Components – POSTFEKO

POSTFEKO: Post processing of simulation results

CADFEKO

POSTFEKO

FEKO Solver

FEKO의시뮬레이션맵&

주파수의연관성


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Solvers in FEKO – Simulation Map E

LE

CT

RIC

AL

SIZ

E

COMPLEXITY OF MATERIALS

FDTD

FEM

MLFMM

MoM

UTD

PO/RL-GO

Full-wave

Methods

(physically

rigorous solution)

Asymptotic

Methods

(high-frequency

approximation)

Hybridization to

solve large and

complex

problems

All solvers included in the

same package


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Short Description of Methods

Method of Moments (MoM)Ideal for radiation and coupling analysis,

being applicable to problems involving

currents on metallic and dielectric structures.

Multi-level Fast Multipole Method

(MLFMM)MLFMM is an alternative formulation of the

technology behind the MoM and is

applicable to much larger structures than the

MoM, making full-wave current-based

solutions of electrically large structures a

possibility.

Finite Element Method (FEM)Ideal for problems with several dielectrics,

including inhomogeneous ones, which are

not efficiently solvable with the MoM.

Finite Difference Time Domain

(FDTD)Ideal for solving highly inhomogeneous

materials and wideband problems.

Physical Optics (PO)High frequency method based on currents,

ideal for electrically very large radiation and

scattering analysis.

Large element PO (LE-PO) is also available.

It uses an alternative set of basis functions

allowing mesh sizes of multiple wavelengths.

Ray Launching – Geometrical Optics

(RL-GO) Ideal for metal or dielectric electrically very

large scattering and radiation analysis. It is a

ray-based technique that models objects

based on optical propagation, reflection and

refraction theory. It is also known as the

Shooting and Bouncing Rays (SBR)

approach.

Uniform Theory of Diffraction (UTD)Ideal for electrically extremely large, PEC

structures, being the method based on rays

(not on currents, like PO).

… and


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Hybridized Methods: Full-wave + Asymptotic Methods

• MoM hybridized with PO, LE-PO, RL-GO, UTD and FEM

• MLFMM hybridized with FEM, PO or LE-PO

Antenna:

MoM region

Coupling

Radiation Hazard Analysis of Cellular

Base Station Antenna using MoM/FEM

Human:

FEM region

MLFMM part

LE-PO region with

larger triangles


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Solvers and Methods under Productivity Features

Features including other methods and

solvers focused on specific analysis,

including:

• Windscreen antenna modelling and

solution method.

• Complete integrated cable modelling tool

with Multiconductor Transmission Line

Method (MTL) launched in 2011.

• Model decomposition using equivalent.

sources of complex sources and receivers

• Large finite array solver.

• Characteristic Mode Analysis (CMA)

method.

Solver Introduction

MoM Since 1991

MoM/PO Since 1992

MoM/UTD Since 1994

MLFMM Since 2004

MoM/FEM Since 2005

MoM/RL-GO Since 2007

MLFMM/FEM Since 2010

MoM/LE-PO Since 2010

MLFMM/PO and

LE-PO

Since 2014

FDTD Since 2014


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Memory Requirement Comparison of MoM and MLFMM

Number of

Unknowns

(N)

MoMMemory: N2

Run-time: N3

MLFMMMemory: Nlog(N)

Run-time: Nlog2(N)Examples

100 000 75 GB 1 GB

Military aircraft at 690 MHz

Ship (115 m x 14 m) at 107 MHz

Reflector antenna with aperture size 19λ

200 000 300 GB 2 GB

Military aircraft at 960 MHz



400 000 1.2 TB 4.5 GB

Military aircraft at 1.37 GHz



1 000 000 7.5 TB 12 GB

Military aircraft at 2.2 GHz




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Electrical Size of an Aircraft

Frequency Electrical Size of Aircraft

Length Wing span

300 MHz 15 λ 9 λ

600 MHz 30 λ 17 λ

1.2 GHz 61 λ 34 λ

2 GHz 101 λ 57 λ

10 GHz 504 λ 284 λ

20 GHz 1009 λ 568 λ

300 MHz 600 MHz 1.2 GHz


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Computation Resource Scaling for Aircraft Model

• Memory and runtime scaling for the SAAB JAS-39 Gripen:

• The results are normalized (300 MHz, MLFMM = 1) to highlight the factor increase in requirements as

a function of increasing frequency

• Furthermore, the graphs highlight the difference between requirements in the MLFMM and PO

methods.

• PO can solve the problem at 20 GHz where the plane is 1000λ long

Solution time scalingMemory scaling

2x Quad core Intel Xeon E5606 CPU, 2.13 GHz (8 processes total), 72 GB RAM Multi-threaded parallel processing was used on all 8 cores


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Cross-Validation of Simulated Results

1.2 GHz 2.0 GHz

Leverage the different solvers to cross-validate the simulated results


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Switching Between Solvers in CADFEKO

다양한응용예에따른적정솔버의적용방법


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Antenna Design – Wire Antennas

MoM for wire antennas

(without dielectrics) MoM also for wire antennas

including dielectrics

(using FEKO’s MoM extensions to deal with

dielectrics, i.e. incl. Planar Green’s function

for infinite dielectrics, SEP for finite

dielectric using surface meshing, VEP for

finite dielectrics, dielectrically coated wires

and the windscreen antenna method)

Using VEP for electrically

small problems where high

permittivity or permeability are

modelled, like a ferrite core

with a wire around it


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Antenna Design – Microstrip and Conformal Antennas

For microstrip antennas, consider:

• MoM with the Planar GF, SEP or VEP

• FEM, MoM/FEM

• FDTDMoM with SEP

MoM with Planar GF

MoM

For conformal antennas, consider:

• MoM

• FEM, MoM/FEM

• MLFMM

• MLFMM/FEM

MoM/FEM


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Antenna Design – Arrays

For antenna arrays, consider:

• MoM, MoM/FEM

• MLFMM, MLFMM/FEM

• FEM

• FDTD

MoM

* Consider also DGFM, PBC and model decomposition

Method Memory Run-time

MoM 166 GB 13.2 hours

MLFMM 92 GB 4.6 hours

FEM 24 GB 0.1 hours

FDTD 2.7 GB 58.4 hours

FEM


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Antenna Design – Windscreen and Wireless / Mobile Antennas

For windscreen antennas, consider:

• Windscreen antenna method with

MoM or MLFMM

For mobile and wireless antennas,

consider:

• MoM, MoM/FEM

• FEM

• FDTD


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Antenna Design – Reflector and Dielectric Lens Antennas

For reflector antennas, consider:

• MLFMM or MLFMM with point source

• PO or LE-PO or RL-GO with point

source

MLFMM

Point

source

RL-GO

For dielectric lens antennas, consider:

• MoM (with SEP or VEP)

• MLFMM

• RL-GO


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Antenna Placement Using MoM

Standard mesh /10

20.434 triangles

30.426 unknowns

Coarse mesh 1.2

987 triangles

15.813 unknowns

Typically use MoM for problems with electrical

sizes of up to 10-15 (and depending on the

available resources)

Rod antenna on MCC Car at 100 MHz

Considering also MoM with High Order Basis Functions (HOBF)

RCS illuminated with a plane wave at 900 MHz


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Antenna Placement using MLFMM

MLFMM MoM

9.80 GBytes 896 GBytes

Antenna array mounted on

Iridium Satellite

Typical uses consider MLFMM for sizes from around 10 of up to 100 (or more

depeding on the available resources)

VHF 126 MHz Antenna

on Bottom Position

Antenna at 1 GHz


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Antenna Placement with Hybrid and Asymptotic Methods

193.212 triangles hybrid MoM/PO

For problems with sizes from 20-30 to 1,000 consider:

• Hybrid methods based on MoM with PO or LE-PO or RL-GO

• Hybrid methods using MLFMM with PO or LE-PO or FEM

MLFMM

LE-PO

SATCOM antenna on aircraft using MLFMM/LE-PO

MLFMM

FEM

2.4 GHz planar array on missile


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Antenna Placement using UTD

For problems with electrical sizes > 500 consider UTD

Example of 10 GHz radar antenna at 10 GHz on 102m long frigate

(and using model decomposition)


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EMC – HIRF, Lightning Analysis or EMP

The aircraft geometry on the first row above is part of the CEMEMC workshop and corresponds to a morphed version of EV55, Intellectual Property of EVEKTOR,

spol. s r.o. and the HIRF SE Consortium (HIRF-SE FP7 EU project)

Magnetic field strength at 50 MHz

Magnetic field strength at 1 GHz

Exit point

Strike point

Antenna 1

Antenna 2Double exponential pulse

Typically consider MoM, MLFMM or FDTD

HIRF Application

Lightning stike on airborne platform (and using time analysis in POSTFEKO)


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Method RAM (GB)

Simulation

time

(hours) Hardware

MoM

(SEP)17.84 1.36

parallel 8x

cluster

FDTD 1.96 0.18

1x GPU,

NVIDIA

Tesla K20c

EMC – Electromagnetic Pulses (EMP) with FDTD

For EMP problems dealing with complex structures and multiple dielectrics

consider FDTD


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EMC – Cable Modelling in FEKO

FEKO also includes a Multiconductor Transmission Line (MTL) method to solve

cable problems, used with FEKO’s field solvers to compute the external fields and

currents that couple to/from such complex cables bundles


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EMC – Cable analysis with MTL and MoM or MLFMM

HIRF impact on systems in a UAV

Coupling analysis between cable

(connecting control electronics in engine

to tail light) and 3G antenna Coupling analysis of radiated PCB emissions

into cable harness and windscreen antenna


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EMC – Shielding Analysis

Example of magnetic

shielding from a steel

sphere from as low

as 60 dB

FEKO

Other CodeFEKO

FEKO

Use MoM with SEP or VEP, including

the high shielding formulation

Consider FDTD for shielding analysis

of complex and detailed structures


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EMC – Radiated Emissions and Immunity

For the simulation of radiated emissions or immunity tests typically consider

MoM or MLFMM

DUT

EMC antenna


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EMC – Radiation Hazard Analysis

For RADHAZ, when no human body models are included, consider MoM and

MLFMM (and hybrid or asymptotic methods if required)


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Radar Cross Section (RCS)

1 10 100 1000

MoM

MLFMM

LE-PO

RL-GO

RCS at 75 MHz (ship length 30)

Model size in

Consider the following methods:

RCS at 10 GHz (ship length 4000)


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Others – Microstrip circuits

Interdigital filter on a

lossy dielectric substrate

with a metallic enclosure

Design and currents on a triple split

ring resonator at 2 GHz

Shunt microstrip spiral

Slotted planar structure

Consider MoM, MoM/FEM, FEM and FDTD


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Others – Waveguide Components and Devices

MoM (SEP) MoM / FEM FEM

Metallic Triangles 4996 7490 6639

Dielectric Triangles 922 2442

Tetrahedral Elements 21228 48106

Modal Port Triangles 326

Runtime per

frequency point **

272 sec 1123 sec 83 sec

Memory per process 277 MByte 784 MByte 190 MByte

Model

** Xeon® E5606 2.13GHz: 4 processes (cores) on 1 CPU

Example of a two-path cut-off dielectric resonator filter to show the solvers to

mainly consider:


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Others – Radomes

Dielectric-layered wall radomes

and FSS radomes

To characterize the radome material use MoM

with the Planar Green’s Functions and PBC

For the radome with antenna:

• MoM or MoM/FEM for small electrical sizes

• For electrical sizes > 7-10 use

• MLFMM

• MLFMM/FEM

• RL-GO with point source

• If the wall of the radome if electrically thin

use MoM, MLFMM or RL-GO with TDS (Thin

Dielecric Sheet)


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Others – Bioelectromagnetics

Antenna:

MoM region

Coupling

Human: FEM

regionMaximum

localised

SAR

High e-field

values

Low

e-field

values

Consider MoM/FEM, MLFMM/FEM or FDTD and when including human body

models


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Others – Bioelectromagnetics in MRI

empty coil

MoM

coil & homogenous

phantom

MoM

coil & anatomical

head phantom*

MoM+FEM

coil & anatomical head

phantom**

FDTD

triangles 514 4038 514 - -

tetrahedral - - 132 572 - -

voxels - - - 2.76 M(4mm phantom) 19.1 M(1.75mm phantom)

runtime < 1 min 12 min 48 min 26 min 5.6 hrs

RAM 4 MB 0.97 GB 3.3 GB 570 MB 2.9 GB

* simulated on a clusters with parallel 8x, ** simulated with GPU acceleration

32 tuning

caps

RF shield

2 voltage

sources for

quadrature

IQ feeding

16 rungs


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Others – Bioelectromagnetics – Human Body Models

Articulated

(parametric)

Human (SEP)

Standing Human

(FEM)

Articulated Hand

(SEP) IEEE Head (SEP)

Visible Human

Full Model

(Inhomogeneous

FEM)

Visible Human

Head and

Shoulders

(Inhomogeneous

FEM)

Visible Human

Head

(Inhomogeneous

FEM)

IEEE SAM

(Homogeneous

FEM)

Hugo (4 Organs

FEM)

Using geometry

cards in

EDITFEKO.

Parametric i.e.

change positions,

sit, stand, raise

arms, bend legs

etc. The mesh

size will change

with frequency and

has been tested

up to 900 MHz.

Model is based on

the Articulated

Human. The

model consists of

334,733

tetrahedrals (8mm

size) and can be

used for runs up to

1GHz. Requires

more than 2

GByte of RAM.

Using geometry

cards in

EDITFEKO.

Change position of

fingers, 16

degrees of

freedom. (Tested

up to 1800 MHz)

This CADFEKO

model is a triangle

mesh of the inner

layer of the IEEE

SAM phantom.

The minimum

triangle length is

10mm. The model

is set up for 1800

MHz. +- 2 GByte

of RAM required.

The model

contains 2.2 mil

tetrahedrals (8mm

size) and is

suitable up to

1GHz. Requires a

64bit machine and

will use +- 10

GByte of RAM.

The model

contains 300,000

tetrahedrals (8mm

size) and can be

used up to 1 GHz.

Can be solved on

a 32bit machine

with 2 GByte of

RAM.

The model

contains 900,000

tetrahedrals (4mm

size) and can be

used up to 2GHz.

Requires a 64bit

machine and will

use more than 2

GByte of RAM.

5mm tetrahedral

mesh of the older

IEEE SAM

phantom and a

20mm tetrahedral

mesh air box

around the head.

The model is set

up for 1800 MHz.

Requires +- 1.4

GByte of RAM

(with hertzian

dipole as antenna

(MoM)).

The model has 5

different media:

brain, lungs, eyes,

muscle and an

outer air shell. The

model contains

749,507

tetrahedrals (8mm

size) and can be

used up to 1GHz.

Requires more

than 2 GByte of

RAM.

All of the above phantoms can also be used with the FDTD solver in FEKO


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Summary Table and Remarks

Remember to check out

www.altairhyperworks.com/feko

Get in touch with Altair Korea

http://www.altairhyperworks.com/feko

감사합니다.

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