Antenna Simulation Overview
Marc Rütschlin, Senior Application Engineer
2011 CST European UGM | 18-19 May 2011 | 1

Antenna Design Flow
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Choosing an antenna...
Antenna Magus
 Explore database
 Design antenna
 Synthesise array
 Estimate performance
 Export!
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Categories of Antennas
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Solver Selection
Technique
Approach
Transient
FIT-T, TLM
Time domain
( Broadband )
Volume – hex
PBA, Subgridding
Finite Element
FEM
Single frequency
Volume – hex, tet
Curved Tetrahedrons
Integral
MOM, MLFMM
Single frequency
Surface
Meshing
Robust
Cheap
Conformal
O(n)
Numerical Effort
Time step?
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Complex
Expensive
Conformal
O(n 2 ...n
3 )
Push button
Complex
Dielectrics?
O(n·log(n) ...n
3 )
No numerical dispersion error

Selected Examples
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Ultra Wideband Antennas
 Direct pulse communication
 Typical frequency range:
3.1 to 10.6 GHz
 Tailored signal
Natural solver choice:
Excited pulse broadband, transient farfield
Received pulses
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Ultra Wideband Antennas
 Design goals for UWB Antenna
 Automatic postprocessing
 optimization goals.
return loss < -10 dB group delay = flat a cross-correlation peak
Correlation Peak
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Mobile Phone Simulation
 Advanced Interface
 Imported Structures
 Bending
 Robust Meshing (PBA)
 Efficient Solvers
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Mobile Phone Simulation
Full Phone Evaluation  Post-processing !
Total radiated power / TIS System simulation
Matching Circuit / Load Pull
MIMO / Diversity
Envelope Correlation
Hearing Aid Compatibility
(HAC)
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Mobile Phone Simulation
Biological Impact:
 of body on phone...
TRP including body model
 of phone on body...
Specific Absorption Rate (SAR)
< 2 W/kg
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RFID – Low Frequency
 Near (H-)field coupling
 Electrically small reader coil tag
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13.56 MHz

RFID – Low Frequency
 Near (H-)field coupling
 Electrically small
λ = 22.2 m 13.56 MHz small size & features small time step!
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0.001 mm gap
= 10 -5 λ!

RFID – High Frequency
 Radiating antenna
 RFID chip
915 MHz
S
11
= -8 dB
NXP G2XM chip
S
11
= -0.3 dB
0.15 mm courtesy of UPM RFID www.upmrfid.com
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RFID – High Frequency
 Radiating antenna
 RFID chip or , depending on antenna
915 MHz
0.15 mm courtesy of UPM RFID www.upmrfid.com
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RFID – High Frequency
 Radiating antenna
 RFID chip
 Tag in situ peaks dips hours...
hours...
4 GB
RAM
25 GB
RAM
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RFID – High Frequency
 Radiating antenna
 RFID chip
 Reader  System
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Reflector Antennas
 Electrically large
 Lots of air!
Options:
1.
full wave simulation
2.
Don’t mesh the volume!
problem
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12 GHz 
λ = 25 mm
400 mm
16 λ

Reflector Antennas
Options:
1.
full wave simulation
2.
split the problem
100 %
10 %
5 %
5 %
1 %
 Use the appropriate solver(s)!
 Optimise the system...
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Assembly Mode in CST DS 2011 reflector farfield as a function of feed geometry

Installed Performance
 Electrically large
 Full wave simulation stacked bicone omnidirectional antenna – 3.5 GHz feed
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Installed Performance
 Electrically large
 Full wave sim.
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Installed Performance
 Electrically large
 Farfield source
Options:
1.
full wave simulation
2.
split the problem
3 hours
3 min 4 min
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Installed Performance
 Electrically large
 Field sources
 Co-site analysis radome
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Small Antenna Arrays
 All elements different
 simulate all!
 Optimise post-processing combination of fields.
1
6
5
6
1
5
2
4
3
1 2 3 4
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2
4
3

Small Antenna Arrays
 All elements different
 simulate all!
 Optimise post-processing combination of fields.
Original beam shape
Optimised beam shape
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Large Antenna Arrays
 Most elements the same
 simulate one.
 HPC  full simulation to account for edge effects.
array factor unit cell boundary condition scan blindness at 45° strong radiation at 30°
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Matching Networks
Coil operating at 13.56
MHz
CST DESIGN STUDIO
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Conclusion
Complete Technology...
Methods to suit any task!
Automated processing of results...
Get the output you want!
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