(electrically) large applications integral equation solver · pdf file(electrically) large...

1 www.cst.com | Mar-09www.cst.com | Mar-09

(Electrically) Large Applications

&

Integral Equation solver

Agenda:

I-Solver Overview

Key Features

Large Structures / Applications

jeb / v1.0 / 03. Mar. 2009

2

I-solver overview

Areas of application

Far-field & RCS computation

S-parameter calculation

For electrically large structures &

mid-size structures (≥ 0.1-1 λ)

Excitations

Waveguide port

Discrete face port

Plane wave

Farfield MP source

Current source

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Discretization by Method of

Moments (MoM)

Surface mesh

Multilevel Fast Multi-Pole

Method (MLFMM)

I-solver is based on …

')'(')'()'()'()( 2 dSrJrrgrJrrgirES

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Idea of MLFMM

MoM

Each element couples to all

other elements

Dense matrices

FMM

Use boxes to combine

coupling

Sparser matrices

MLFMM

Recursive scheme

O(N log N) complexity

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I-solver – Solver overview

Direct & iterative solvers (MoM, MLFMM)

Automatic pre-conditioning

Higher order element discretization

Up to 3rd order discretization including mixed order

Open & electric boundary conditions

Perfect ground plane

Automatic surface mesh generation

Automatic mesh refinement at critical edges

NASTRAN mesh import

1st order

2nd order

3rd order

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Key features of I-solverI-solver – Integral Equation solver

7

New Features – I-solver 2009

Specific features for large structures

Multi-pole field source

Current source

Infinite ground-plane

Fast Farfield calculation (for MLFMM solvers)

Higher accuracy & speed for the radiated power

calculation

Some examples…

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Multipole Field Source excitation

Example: Dipole

Reference simulation

1. Simulation with FFsource

2. Simulation with FFsource & Multi-poles

Dialog

www.cst.com Mar-09

9

Multipole Field Source excitation

Example: Dipole

Reference simulation

1. Simulation with FFsource

2. Simulation with FFsource & Multi-poles

Reference FFsource FFsource & MP

Nearfields are better,

if multi-poles are considered

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Current source (Definition)

CableMod

*.rsd file

I-Solver supports rsd file format:

Filamentary source

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Current source (Solver Setup)

1. Select Source type: List

2. Click on Select...

3. Choose excitation

4. Specify frequency samples

5. Start simulation

All standard results and I-solver monitors are available.

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Current field source excitation

Excitation at 250 MHz

1st order MLFMM-AP

3min sim. time

Nastran import

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Current field source excitation

Excitation at 250 MHz

1st order MLFMM-AP

3min sim. time

E-field on surface

Surface current

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Infinite Ground-plane

Spiral antenna over ground plane

74mm, 5-6 GHz, ~1.5λ

1st order, 2.500 dof, 100 MB, ~30min

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Antenna Applicationsfor electrically large structures

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Applications – Aircraft at 4 GHz

26.4m x 26.6m x 7.7m 352λ x 355λ x 103λ at 4 GHz

780.000 unknowns, 1st order MLFMM

Surface mesh

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Aircraft with antenna at 4 GHz


780.000 unknowns, 1st order MLFMM

Dipole antenna on top of fuselage

3D Farfield plot

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1.3M Surface mesh cells, 1st order MLFMM

3D Farfield plotSurface currents

Surface mesh

Apache Helicopter at 17 GHz

Bi-conical

antenna

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Electrically large applications

Ship & sea water (ε=80),

25 MHz

143x30x3.5m

Mono-pole

antenna

Far-field

Surface current

Horn feed

17cm

Far-field

Dielectric lens (ε=2.53),

34.5 GHz

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900 MHz simulation for buildings

(outdoor/indoor)

Surface mesh

Simulation time: 5h 46min

Memory: 60 GB, 818k surface cells

Farfield source

Excitation

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Dimensions of the buildings

25m

25m

7.5m

8.6m

2m

20mConcrete

Dry soil

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Results at 900 MHz

3D-Farfield

E-field, clamped to 1 V/m

outside

inside

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Horn antenna with dish at 30 GHz

Radiation pattern

50λ

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360° RCS analysis, 0.5

GHz

13mMono-static RCS

(horizontal plane)

1° step size

Incident

plane wave

direction

Plane

wave8m

Tank on ground, 1 GHz

Far-field

Surface current

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Integral Equation solverSummary

Best for electrically large structures

Optimal complexity (memory & time)

Arbitrary material combination

Various excitations

Embedded in CST MICROWAVE STUDIO®

Antenna applications:

Farfield MP source

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