cst installed performance

7/21/2019 CST Installed Performance

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Modeling the InstalledPerformance of Antennas in a

Ship Topside Environment

CST COMPUTER SIMULATION TECHNOLOGY | www.cst.com | Nov-10

Enow Tanjong


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Electromagnetic SystemsComplete Technology in Action

Antenna

Filter Shielding

RCS

Installed Performance


Electron Tube

FSS

Array

Connectors PCB

Package

Cabling


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System Level Design

All-Encompassing EM-Simulation

EM Interaction

System analysis

Coupling analysisRadiation analysis


Installed PerformanceEMC/ EMI/ E3

Challenges: Electromagnetic size, Complexity, Aspect ratio


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Electrical SizeFrequency Application

1 MHz Lightning

10 MHz HF communications

100 MHz EMP

1 GHz L-Band

Communications

10 GHz Radar


El. Length

0.5

5

50

500

5000

FEM TD MLFMM AsymptoticMoM


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Aspect Ratio

300 MHz

18 m

18

1.575 GHz

160 m

840


4 mm notches

0.9 mm radius feed pin3 mm wire radii


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Approach 1: Brute force!


Small detail small time step longer simulation.

HPC options: CPU, GPU, MPI.

Mesh quality important Increased meshing in small

detail leads to high memory

requirement

HPC options: CPU, MPI.

MLFMMTime Domain


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Approach 2: Field DecompositionFIT, TLM, FEM, MoM, MLFMM


Near-field source

Far-field source

FIT, TLM

MoM ,MLFMM, Asymptotic


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Advantages of Field Sources

Near-field Source Far-field Source


Small simulation volume fine features can be simulated

accurately.

Simulate source with appropriate mesh and solver.

Can import external (measured) fields.

No knowledge of antenna structure necessary (Intellectual Property).


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Real World Navy Frigate

Complete Technology in Action

1 GHz JTIDS antenna(FEM + MLFMM)


10 MHz HF whips (TD, MoM)


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TD (FIT) Solution


FIT Solver

40 minutes, 1.3 GB RAM10 Million mesh cells


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Far-Field Results at 10 MHz

Single antenna excited



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Surface Current due to HF Antenna



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MoM SolutionMoM Solver

60 minutes, 12 GB RAM


Low frequency stabilization available

Anisotropic mesh

refinement


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JTIDS for L Band TDMA Network RadioJTIDS antenna (1.0875 GHz)


Installed performance of antenna required


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JTIDS Antenna Array Design


Rapid, automaticdesign of validatedantenna elements

Convenientbuilding block forlarger, morecomplex designs

Synthesis, Optimization


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Element Level Simulation


Snap nodes to boundaryReferences true geometry


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Sensitivity Analysis


Sensitivity AnalysisParametric tolerance analysis with only a single simulation run


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2nd Order325000 Tetrahedrons

Mixed Order Elements


3rd Order Mixed98000 Tetrahedrons


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JTIDS Antenna Pattern in Isolation


Automatic phasecenter calculation

Arbitrary slantpolarization


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JTIDS Far Field Source on Ship

JTIDS antenna patternimported and

positioned on ship mast


Ship is 500 wavelengths long @ 1.0875 GHz


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Characterization of Water Surface


At higher frequencies

characterization of sea water as asurface impedance materialsignificantly reduces the amount ofrequired computational resources


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Surface Mesh at 1.0875 GHz


, , sur aces

MLFMM Solver => 12 hours and ~84 GB RAM


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JTIDS + Ship Results at 1.0875 GHzSurface current



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Complex Ship Model

USS Winston S. Churchill (DDG-81)

Provided by



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Tactical Air Navigation (TACAN) Antenna


1.087 GHz TACAN antennaGain cut

3D Far-field

Antenna Gain not optimized


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TACAN AntennaGain



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TACAN Far Field Source on Ship

TACAN antenna patternimported and positioned



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TACAN Far Field + Ship meshed at 1.087 GHz

1,950,098 surfaces (including seawater) => Solvable with MLFMM

but would require a large amountof RAM. MPI would be an option



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Asymptotic SolutionShooting Bouncing Ray (SBR) method Multiple bounces taken into account Plane wave source for RCS analysis Incident Rays

Scattered Rays


Robust meshing enables discretization of complex models and Asymptotic solutionrequires far less computational resources making it ideal for this problem


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TACAN + Ship Results at 1.087 GHz


Asymptotic solver => 3 hours, 600 MB RAM

Model size is approximately 783 wavelengths at 1.087 GHz


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S-Band Radar Antenna



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Radar Unit Element Patch Antenna


Right-hand Circular Polarized pin-fed

Square Truncated Patch Antennadesigned for 3 GHz


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Array Construction and Excitation

Array wizard constructsthe array and applies

excitation

25 X 25 Array

Transient Solver


All 625 Ports created

automatically by wizard


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3 GHz S-Band Radar Array Results

Far-field

Surface Current


Simultaneous port excitation requiring 35 GB ofRAM and 6 hours to run


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S-band Radar Antenna Field source on Ship


Radar Antenna Array Patternimported and Positioned


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Single Radar + Ship Results at 3 GHz

Far-field


Model size is approximately 2160 wavelengths at 3 GHz


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Multiple Far-Field Sources

Possible to import multiple FFsources and excite all at once



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Antenna Analysis/Placement Features

All standard antenna performance results (Gain, Surface Current, . . )

Sensitivity analysis

Up to 3rd order TET elements

Frequency tabulated surface impedance


arame er za on op m za on

Far-field and Near-field Source imports

Array Wizard

High Performance Computing Options


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Summary

CST MWS has the capability of solving electromagnetic problems both

at the component level and at the system level

The complete technology available means the best tool can be used for

a particular analysis


e sys em eve e ecompos on ec n ques can e use or

more efficient analysis.

The asymptotic method implemented in CST MWS can be used for very

complex electrically large simulations reduce the amount of resources

required

cst installed performance

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