faustus - worcester polytechnic institute
TRANSCRIPT
Multi-Level Modeling of Complex Systems and
Advanced Materials with MEFiSTo
Wolfgang J.R. Hoefer
FaustusScientific Corporation
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 2
Contact Information
Faustus Scientific Corporation1256 Beach Drive Victoria, BC, V8S 2N3Ph. (250) 592-6554 Fax: (250) 592-6557 Email: [email protected]://www.faustcorp.com
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 3
Outline
IntroductionMEFiSTo – The Tool and its ArchitecturePrincipal and Unique FeaturesModeling Examples Benchmark: Potato in a MW-OvenSummary
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 4
Presentation of MEFiSTo
Multipurpose Electromagnetic Field Simulation Tool
Simulation Engine: TLM in Time DomainObject-Oriented Program, C++Multi-Thread ArchitectureReal-Time links to other tools enabling multi-level field/circuit/neural network/ thermal/mass transfer simulations
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 5
Frequency Domain Simulators
Time Domain Simulators
Time Harmonic (single frequency)
Transient (wide bandwidth)
Implicit algorithm [M][x] = [g]
Explicit algorithm [xn+1] = [S][xn]
(FEM, MoM, FD, FIT) (TLM, FDTD, TDFEM, TDFIT)
MEFiSTo
Frequency vs. Time Domain
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 6
TLM Modeling Environment
TLM is a discrete network model of the 3D Maxwell Equations;It can be operated either in the time or in the frequency domain;Time domain modeling with TLM involves a sequence of impulse scattering and transmission (connection) operations.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 7
The TLM Algorithm
The three basic TLM operations:
MEFiSTo operates exclusively in the time domain
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 8
Advantages of TLM
Less dispersive than other time discrete schemes.Passive network model is always unconditionally stable.Scattering algorithm is numerically more robust than finite difference formulations [Fettweiss].Due to co-location of electric and magnetic fields it is easy to connect devices and implement boundaries.(SPICE-EM-bed, MatLab Link, Thermal Engine)TLM modeling invokes expertise in field theory, network and circuit theory, and signal processing. It is a “physical” field model.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 9
Computational Burden
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 10
FDTD vs. TLM
f= 60 GHz ; ∆l= 1 mm =λ/5
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 11
Theory and Laboratory
MEFiSTo-3DSimulator
LaboratoryTheory
MEFiSTo builds on traditional theory and laboratorypractice and extends them through modeling and simulation
Modeling Simulation
Transmission Line Theory, Maxwell’s Equations
Network Analyzer, Spectrum Analyzer, Oscilloscope, etc.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 12
How does MEFiSTo work?
Enter/import geometry & el.-mag. properties,Set up source(s), probes, reference planes,Set discretization parameters and mesh,Specify source waveform,Extract time response at probes or bounds,Extract S-parameters, radiation pattern,Visualize fields, responses, characteristics,Analyze, optimize, export, store, print data, graphs, field plots, results.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 13
The Modeling Engines
Engine Manager
Electrom
agnetics
SPICE
Wood D
rying
Food Processing
Biom
edical
MD
SD
VD
Error HandlingModule
Core TLM EngineM
atLab
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 14
Field ResponseLine GraphsBar Graphs
The Signal Co-Processor
Time Domain Frequency Domain Space Domain
Data-BrokerVD
Options Options Options
MagnitudePhase
ScatteringParameters
MeshColor
ContourVector
Window Window Window
All data can be displayed dynamically as they are generated
DFT
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 15
Features of MEFiSTo-3D
Electromagnetic modeling software tool with transient and time-harmonic capability;Accuracy, ease of use, versatility, speed;User-friendly lab-inspired graphical interface, fully parameterized, controllable externalIy;Runs under all current Windows operating systems, 64-bit version in preparation;Dynamic field visualization in space and time;Automatic window capture for movie creation;Co-processing instead of post-processing provides unprecedented interactivity.
… continued
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 16
Features of MEFiSTo-3D
Multi-threaded architecture for multiple platforms; smart memory allocation;Text-based data import and export;Customized library of user-defined structure elements;SPICE-EM-bed capability allows coupled circuit-field simulation and circuit embedding;MatLab link for multi-level processing;Batch processing capability for automatic data base and reduced order model (SPICE modules, neural networks) generation;2D and 3D metamaterial modeling capability.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 17
MEFiSTo - A Virtual Laboratory
ModelingEngines
Reference probe
Input probe
Output probeReference probe
Input probe
Output probe
StimulusInput VoltageOutput Voltage
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 18
Typical MEFiSTo Applications
MEFiSTo as a Virtual Network Analyzer (VNA) and design tool;MEFiSTo as a Virtual Time Domain Reflecto-meter (VTDR), Signal Integrity & EMC tool;MEFiSTo as a virtual kiln, food pasteurizer, or microwave oven;MEFiSTo as a virtual design and test environ-ment for advanced materials and components;MEFiSTo as a virtual teaching and traininglaboratory providing physical insight into the relationship between field behavior and circuit or system properties.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 19
MEFiSTo as Virtual Network Analyzer
SweepSignal Generator Splitter
DUT
Comparator Display
Test Channel
Reference Channel
Network Analyzer
Identical WidebandSources Comparator Display
InputOutput
Reference
DUT
TD Simulator
Reference Structure
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 20
Modeling of Wood Drying
Electromagnetic Fields: TLM3D Spatial Transmission Line Network, CartesianDiagonal tensor permittivityTime-dependent ε’ and tanδ (functions of moisture content and temperature.
Heat Diffusion: FDTDFDTD mesh overlaps TLM meshForward Time Central Space (FTCS) Scheme)Temperature and moisture dependent diffusivity tensor (diagonal)
Mass Transfer: FDTDSame as Heat Diffusion
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 21
The Coupled Kiln Model
E/M Field in the Kiln
( )
( )Et
JH
Ht
E
r
r
ε
µ
∂∂
+=×∇
∂∂
−=×∇
RF Energy deposited in Wood
Moisture and Heat TransferQT
tTc
MDt
M
Tp
M
+∇∇=∂∂
∇∇=∂
∂
)(
)(
λρ
TLM
FDTD
δε tan,r Q
Reach steady state after material changes
Compute until proper-ties change by 1 %
wood density energyheat diffusion coeff.
specific heat
moisture diff. coeff.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 22
Modeling of Food Pasteurization
Electromagnetic Fields: TLM3D Spatial Transmission Line Network, Cartesian Diagonal tensor permittivityTime-dependent ε’ and tanδ (functions of temperature.
Heat Diffusion: FDTDFDTD mesh overlaps TLM meshForward Time Central Space (FTCS) Scheme)
Mass Transfer: not considered (sealed food packages)
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 23
Coupled Food Pasteurization Model
E/M Field
( )
( )Et
JH
Ht
E
r
r
ε
µ
∂∂
+=×∇
∂∂
−=×∇
RF Energy deposited in Food
Heat Transfer
QTtTc Tp +∇∇=
∂∂ )(λρ
TLM
FDTD
δε tan,r Q
Reach steady state after material changes
Compute until proper-ties change by 1 %
food density energyheat diffusion coeff.
specific heat
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 24
Coupled EM-Thermal Engine
CoupledSimulation
Cycle
UpdateMaterial
Properties
HeatConduction
HeatConvection
HeatRadiation
GSCN TLMAnalysis Continue
yes
no
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 25
43mm
86mm
70mm
PVC
15mm
20.5mm11.5mm PVC
45mm
40mm
20mm
Simulation Example
PVC Block in a Rectangular Cavity
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 26
Transient Radiation from Circuits
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 27
Application of Diakoptics
Nonlinear Sub-structure
Simulate only once,Store impulse response
Partition
Reconnect by convolution
Linear Sub-structure
Nonlinear Sub-structure
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 28
Impulse Excitation
Matched Load
Probe
The impulse response of the passive part of an oscil-lator is computed, picked up by the probe and stored
Response of Passive Circuit
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 29
Connection to the Active Diode
Full oscillator
The active part of the oscillator is terminated by convolution in a Johns boundary characterized by the impulse response
of the passive part. It behaves exactly as the full oscillator
Diode
Active part only, terminated in a Johns boundary
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 30
General SPICE-TLM Interface
==
Port1
Port2
Port 3
3-PortSPICECircuit
Port1
Port2
SPICECircuit
1
SPICECircuit
2
TLM Substructure
TLM Superstructure
Three-Port SPICE Circuit or Deviceembedded in a TLM Superstructure
TLM Field Subdomain embeddedbetween two external SPICE Circuits.
=
=
=
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 31
TLM - SPICE Connection
= SPICECircuit
ZTLM
kVTLM=2kVi
t=k∆t
TLM-SPICE Interface (port)
The TLM impulses incident at the kth time step upon the SPICE port are represented by an equivalent voltage kVTLM=2kVi connected to the SPICE circuit at time k∆t through an equivalent real reference impedance ZTLM which depends on the port topology.
kV1
The SPICE circuit may
contain sources
Initial Conditions
State Vector
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 32
Spice Circuit Dialog Box
paste
Transient Amplifier Response
voltage-coupled
current-coupled
R1R15050ΩΩ
RcRc5050ΩΩ
R2R25050ΩΩ
ReRe5050ΩΩ
Rs2Rs25050ΩΩ
Rs1Rs15050ΩΩ
C1 1nC1 1n
Ce Ce 1n1n
C2 1nC2 1n
VccVcc15V15V R1R1
5050ΩΩRcRc
5050ΩΩ
R2R25050ΩΩ
ReRe5050ΩΩ
Rs2Rs25050ΩΩ
Rs1Rs15050ΩΩ
C1 1nC1 1n
Ce Ce 1n1n
C2 1nC2 1n
VccVcc15V15V R1R1
5050ΩΩRcRc
5050ΩΩ
R2R25050ΩΩ
ReRe5050ΩΩ
Rs2Rs25050ΩΩ
Rs1Rs15050ΩΩ
C1 1nC1 1n
Ce Ce 1n1n
C2 1nC2 1n
VccVcc15V15V
Transient Amplifier Responses
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 35
Interoperability with MatLab
=
Port1
=
Port2
MatLabModule
2
MatLabModule
1
EM Substructure
=
Port1
=
Port2
=
Port3
3-PortMatLabModule
EM Superstructure
Three-Port MatLab moduleembedded in a EM Superstructure
EM Field Subdomain embeddedbetween two external MatLab modules.
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 36
Root Solver
v
i
MEFiSTo’s IV Module
IV-Interface
Pipe & ActiveX
Module Library
Incident Voltage
ReflectedVoltage
Built-inModels
MatLab*.m Models
User-Defined*.exe Models
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 37
Metamaterials
Metamaterials with negative refractive index, (left-handed materials) have two unusual but related electromagnetic properties (Veselago, 1967):
E
Hvph
vg
S
k
0 , 0 ; <<−= rrrr εn µεµ
negative phase velocity
1) The phase velocity is opposite to the group velocityand the flow of energy,
k
k’
k0
air (n=1)
n>0
n>0
negative refraction
2) Waves are refracted at a negative angle (Focusing).
θθ’
-θ’
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 38
Loaded Line ModelCourtesy of A. K. Iyer and G.V. Eleftheriades, UoT
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 39
Modeling of Metamaterials
z
yx
2C0 2C0
2C0
2C0
L0
2/' l∆nL
2/' l∆nL
2/' l∆nL
l∆nC '
2/' l∆nL
Unit Cell of a 2D Metamaterial Model (Eleftheriades et al.)
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 40
Modeling of Metamaterials
TLM Shunt Node Implementation of the Eleftheriades model
z
yx
2/l∆
2/l∆
sZsZ
sZ
sZ
pZ
l0Z l0Z
l0Z
l0Z
1
2
3
4i
k v2r
k v2
isk v 2
rsk v 2
rpk v
ipk v
n=2
n=-2
movie
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 41
Negative Refraction
A wave emitted by a point source is focused in the metamaterial-filled half-space due to the negative angle of refraction.
The refraction angle is negative since the tangential component of the phase velocity must be continuous at the interface, as shown in the diagram above. The focusing effect and the negative phase velocity are confirmed by the MEFiSTo simulation.
MetamaterialAir
n = 1 n = -2
k1 k2k1t k2t
Point source
Focus
MetamaterialAir
n = 1 n = -2
k1 k2k1t k2t
Point source
Focus
θ1 θ2 is negative !!
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 42
Pendry’s Super Lens John Pendry showed in 2000 that double negative refraction can be harnessed to create a perfect image of a point source. Pendry’s lens outperforms classical lenses since it reconstitutes the near-field as well as the far-field of the source with sub-wavelength resolution.MEFiSTo visualizes this fo-cusing action in all its com-plexity, confirming Pendry’s theory as well as recent measurements made by Eleftheriades et al.
MetamaterialAirn = 1 n =
Point source Image
Airn = 1-1
dd/2 d/2
InternalFocus
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 43
Metamaterial Prism
Refraction of a Gaussian beam in a regular prism (a) and a metamaterial prism (b) computed with MEFiSTo-3D Pro
(a) (b)
RefractiveIndex
n=1.414
RefractiveIndex n = -1
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 44
Conclusions
MEFiSTo Electromagnetic Simulators• Extend traditional theory and laboratory work,• Involve both the intellect and the intuition,• Invite and facilitate experimentation,• Are suitable for design, research, and education• Emulate major instrumentation, such as:
- TDR - Network Analyzer- Oscilloscope - Spectrum Analyzer- Signal Processor - Video System
7 January 2005 7th Seminar "Computer Modeling and Power Industry" 45
Conclusion and Outlook
MEFiSTo Time Domain Simulators are among the most general and versatile tools for electromagnetic modeling;They are easy to use by practitioners because they operate like a virtual electromagnetics laboratory;They are suitable for design, research, and education;They can be easily interfaced with other powerful tools;Research is continuing on many fronts:
Sensitivity Analysis based on Adjoint Modeling;Direct electromagnetic synthesis;Design of artificial materials with exotic properties;Distributed and parallel computing; Multi-level modeling and device – field interactions;Time domain neural network models.