muri progress review: electromagnetic simulation of antennas and arrays with accurate modeling of...
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MURI Progress Review:Electromagnetic Simulation of Antennas and
Arrays with Accurate Modeling of AntennaFeeds and Feed Networks
PI: J.-M. JinCo-PIs: A. Cangellaris, W. C. Chew, E. Michielssen
Center for Computational ElectromagneticsDepartment of Electrical and Computer Engineering
University of Illinois at Urbana-ChampaignUrbana, Illinois 61801-2991
Program Manager: Dr. Arje Nachman (AFOSR)
May 17, 2005
Problem characteristics
Problem Description
Distributed feed network
Antenna array elements
Antenna/platform interactions
Problem configuration
Complex structures Complex materials Multi-layers Passive/active circuit elements
Complex structures Complex materials Active/nonlinear devices Antenna feeds
Very large structures Space/surface waves Conformal mounting
Simulation techniques
Solution Strategy
Distributed feed network
Antenna array elements
Antenna/platform interactions
Problem configuration
Time/frequency- domain FEM
Time/frequency-domain FEM & IE
MLFMA/PWTD coupledwith ray tracing
Broadband macromodel
FE-BIcoupling
Accurate Antenna Feed Modeling Using the Time-Domain Finite
Element Method
Z. Lou and J.-M. Jin
Center for Computational ElectromagneticsDepartment of Electrical and Computer Engineering
University of Illinois at Urbana-ChampaignUrbana, Illinois 61801-2991
Typical Feed Structures
Antenna element (opened for visualization of interior structures)
Details showing coaxial cable, microstrip line and radial stub.
Feed Modeling1. Probe model (Simple & approximate)
2. Coaxial model (Accurate)
At the port:
Mixed boundary condition:
1
TM
1
TETEM00
inc
0
inc
),(),(),(
),(
m
zmm
m
zmm
jkz
m
zmm
mm
m
eyxbeyxaeyxa
eyxa
eeeE
eEE
SPn on)(ˆ incUEE
Waveguide Port Boundary Condition
SPn on)(ˆ incUEE
By mode decomposition:
1
TMTM2
TE
1
TETEM0
TEM00)(
m S
mmm
S
mm
mm
S
dSk
dSdSP
Eee
EeeEeeE
1
incTMTM2
incTE
1
TE
incTEM0
TEM00
incinc ˆ
m S
mmmS
mm
mm
S
dSk
dS
dSn
EeeEee
EeeEU
Feed Modeling
Frequency-domain operators: Time-domain operators:
Inverse LaplacianTransform
tc
1
*)(1
thtc mm
*)(1
tgtc mm
)()()( 1 tuctkJt
kth cm
cmm
)()()()()( 02
1 tuctkcJktuctkJt
ktg cmcmcm
cmm
c
s 0
22 / cskcmm
22
22
/ csk
kk
cmm
js
sfrequencie cutoff:cmk
Conversion to Time Domain
Time-Domain WPBC
inc)(ˆ UEE Pn
1
TMTM
TE
1
TETEM0
TEM0
)(
)()()(
m S
mm
S
mm
m
S
dS
dSdSP
Eee
EeeEeeE
inc inc TEM TEM inc0 0
TE TE inc
1
TM TM inc
1
ˆ ( )
( )
( )
S
m mm S
m mm S
n dS
dS
dS
U E e e E
e e E
e e E
L
H
G
Time-Domain Formulation:
Assume dominant modeincidence:
incidence TMdominant )(2
incidence TEdominant )(2
incidence TEM)(2
incTM1
incTE1
incTEM0
inc
f
f
f
e
e
e
U
Monopole Antennas
mm 1.0a
mm 2.3b
mm 32.8h
mm 1.0a
mm 2.3b
23.1 mmh
' 2.0 mmh o30
Measured data: J. Maloney, G. Smith, and W. Scott, “Accurate computation of the radiation from simple antennas using the finite difference time-domain method,” IEEE Trans. A.P., vol. 38, July 1990.
Five-Monopole Array (Geometry)
unit: inch
Finite Ground Plane:• 12’’ X 12’’• Thickness: 0.125’’
SMA Connector:• Inner radius: 0.025’’• Outer Radius: 0.081’’• Permittivity: 2.0
Monopole Array (Impedance Matrix)1 2 3 4 5
5
4
3
2
1
Feeding mode: Port V excited, Ports I-IV terminated. Freq: 4.7GHz
Monopole Array (Gain Pattern)
= 135o
= 45o= 0o (x-z plane)
= 90o (y-z plane)
2 X 2 Microstrip Patch Array
unit: inch
Substrate:• 12’’ X 12’’• Thickness: 0.06’’• Permittivity: 3.38
SMA Connector:• Inner radius: 0.025’’• Outer Radius: 0.081’’• Permittivity: 2.0
Patch Array (Impedance Matrix)1 2 3 4
4
3
2
1
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z11)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z12)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z13)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z14)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z21)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)Real(Z22)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z23)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z24)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z31)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z32)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z33)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z34)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z41)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z42)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z43)
2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4
-50
0
50
100
150
200
Frequency(GHz)
Input Im
pedance(O
hm
)
Real(Z44)
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z11
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)In
put Im
pedance(O
hm
)
Z12
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z13
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z14
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z21
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)Z22
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z23
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z24
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z31
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z32
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z33
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z34
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z41
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z42
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z43
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
2.85 2.9 2.95 3 3.05 3.1 3.15
-300
-200
-100
0
100
200
300
400
500
600
Frequency(GHz)
Input Im
pedance(O
hm
)
Z44
Re(Z) - FEBIIm(Z) - FEBIRe(Z) - FETDIm(Z) - FETD
Impedance Matrix (FETD vs FE-BI)
Patch Array (Gain Pattern at 3.0GHz)
y-z plane
x-z plane
_
_
+
+
oo
oo
0180
1800
Phasing Pattern:
Feeding mode:
Antipodal Vivaldi AntennaReflection at the TEM port
“The 2000 CAD benchmark unveiled,”Microwave Engineering Online, July 2001
Radiation patterns at 10 GHz
Antipodal Vivaldi Antenna
H-plane
E-plane
Layer-by-Layer Finite Element Modeling of Multi-Layered
Planar Circuits
H. Wu and A. C. Cangellaris
Center for Computational ElectromagneticsDepartment of Electrical and Computer Engineering
University of Illinois at Urbana-ChampaignUrbana, Illinois 61801-2991
Layer-by-Layer Decomposition
3D global meshing replaced by much simpler
layer-by-layer meshing 2D-meshing used as footprint for 3D mesh in each
layer 3D mesh developed from its 2D footprint through
vertical extrusion If ground planes are present, they serve as
physical boundaries between the layers
Otherwise mathematical planar surfaces are used to
define boundaries between adjacent layers
Example of Layer-by-Layer Mesh Generation
Layer-by-Layer FEM Solution
FEM models developed for each layerOverall solution obtained is developed through enforcement
of tangential electromagnetic field continuity at layer boundaries Assuming solid ground plane boundaries, layers interact through
via holes and any other apertures present in the model
Direct Domain Decomposition-Assisted Model Order Reduction (D3AMORe) Reduced-order multi-port” macromodels developed for each
layer with tangential electric and magnetic fields at the via holes and apertures in the ground planes as “port parameters” On-the-fly Krylov subspace-based broadband multi-port
reduced-order macromodel generationOverall multi-port macromodel constructed through the
interconnection of the individual multi-ports
50-Ohm microstrip
50-Ohm stripline
gap
Absorbing boundary box
Surface-mount cap
Via hole
Tunable bandpass filter with surface-mounted caps:
Demonstration
The filter is decomposed into a microstrip layer and stripline layer.Ground planes are solid; hence, coupling between layers occurs through the via holes.
microstrip layer (top) stripline layer (bottom)
Connecting ports
Input/output portsConnecting ports
Pins used to strap together top andbottom ground planes
Two Signal Layers
2 2.5 3 3.5 4
x 109
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Frequency(Hz)
S1
1
2 2.5 3 3.5 4
x 109
0.8
0.82
0.84
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
Frequency (Hz)
S1
1
Reference Solution: Transmission line model with ideal 10 fF caps for modeling the gaps. Impact of vias is neglected.
D3AMORe FEM Solution (w/o surface-mounted cap)
Tunable band-pass filter (cont.)
2 2.5 3 3.5 4
x 109
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Frequency (Hz)
S1
1
Open0.2pF, 0.05nH0.5pF, 0.05nH1pF, 0.05nH
Tunable band-pass filter (cont.)
Use of surface-mounted caps help alter the pass-band characteristics of the filter
Hybrid Antenna/Platform Modeling Using Fast TDIE Techniques
E. Michielssen, J.-M. Jin, A. Cangellaris,
H. Bagci, A. Yilmaz
Center for Computational ElectromagneticsDepartment of Electrical and Computer Engineering
University of Illinois at Urbana-ChampaignUrbana, Illinois 61801-2991
Higher-order TDIE solvers TDIE solvers for material scatterers TDIE solvers for surface-impedance scatterers TDIE solvers for periodic applications TDIE solvers for low-frequency applications Parallel TDIE solvers PWTD based accelerators TD-AIM based accelerators
More accurate (nonlinear) antenna feed models More complex nonlinear feeds More accurate S- / Z- parameter extraction schemes Symmetric coupling schemes between different solvers (including cable
– EM interactions)
Progress in TDIE Schemes
Resulting from this MURI Effort
Previous code
Added
1) A higher-order MOT algorithm for solving a hybrid surface/volume time domain integral equation pertinent to the analysis of conducting/inhomogeneous dielectric bodies has been developed
2) This solver is stable when applied to the study of mixed-scale geometries/low frequency phenomena
3) This algorithm was accelerated using PWTD and TDAIM technology that rigorously reduces the computational complexity of the MOT solver from to
4) H1: Linear/Nonlinear circuits/feeds in the system are modeled by coupling modified nodal analysis equations of circuits to MOT equations
5) H2: A ROM capability was added to model small feed details
6) H3: Cable feeds are modeled in a fully consistent fashion by wires (outside) and 1-D IE or FDTD solvers (inside)
2( log )T S SO N N N2( )T SO N N
Code Characteristics
Ground plane
r
Dielectric substrate2.33
Nonlinear Feed: Active Patch Antennas
*B. Toland, J. Lin, B. Houshmand, and T. Itoh, “Electromagnetic simulation of mode control of a two element active antenna,” IEEE MTT-S Symp. Dig. pp. 883-886, 1994.
Nonlinear Feed: Reflection-Grid Amplifier
Amplifier built at University of Hawaii, supported through ARO Quasi-Optic MURI program.
Pictures from A. Guyette, et. al. “A 16-element reflection grid amplifier with improved heat sinking,”
IEEE MTT-S Int. Microwave Symp., pp. 1839-1842, May 2001.
INE
OUTE
Each chip is a 6-terminal differential-amplifier that is 0.4 mm on a side
RF input
Bias
RF Output &Bias
280
355 1 pF
30
280
355
1 pF
30
RF input
Bias
Bias & RF Output
*A. Guyette, et. al. “A 16-element reflection grid amplifier with improved heat sinking,” IEEE MTT-S Int. Microwave Symp., pp. 1839-1842, May 2001.
Nonlinear Feed: Reflection-Grid Amplifier
Ground layerTop metallization (Antenna array)
Signal Layer
Power layer
Bottom layer(electronics)
Footprint ofDigital Chip
Ground island for microwave sources
Microwave signal traces
Digitalswitching currents
Microwavegenerators
r
Dielectricsubstrate 2.2
12 cm8.0 cm
4 m
m
1
2
5
7
34
8
6
11
109
Interfacing with ROMs:Mixed Signal PCB with Antenna
- Full-wave solution only at the top layer
- Dimension of the 11-port macro-model: 623
- Bandwidth of macro-model validity: 8 GHz
- Plane wave incidence & digital switching currents
1000 V/m1000 V/m
x
y
EE
x
z
y
incE
k̂ 4 GHz 3 GHzf
Interfacing with ROMs:Mixed Signal PCB with Antenna
3 m
1.3
m1.5 m
r
Glass windowsthickness: 2.5 cm
2.25
12 cm
8 cm
incE
k̂-1000 V/mzE
0.6 GHz 0.4 GHzf
Interfacing with ROMs:Mixed Signal PCB with Antenna
incE
k̂
Received at port 8
-1000 V/mzE 0.6 GHz 0.4 GHzf
Interfacing with ROMs:Mixed Signal PCB with Antenna
13.3 m3.4 m
16.6 m
rGlass windows, 2.25thickness: 3 cm
Coaxial cablesShield radius: 3 mm
King Air 200King Air 200
Cable Feeds: TD LPMA Analysis
Antenna feed-point
Antenna feed-network
Cable Feeds: TD LPMA Analysis
* Dielectrics not shown25 MHz 52 MHz
61 MHz 88 MHz
Cable Feeds: TD LPMA Analysis
Using Loop Basis to Solve VIE, Wide-Band FMA for Modeling Fine Details, and a Novel Higher-Order Nystrom
Method
W. C. Chew
Center for Computational ElectromagneticsDepartment of Electrical and Computer Engineering
University of Illinois at Urbana-ChampaignUrbana, Illinois 61801-2991
Volume Loop Basis Advantages:
Divergence free Less number of unknowns (A reduction of 30-40%) Reduction in computation time Easier to construct and use than other solenoidal basis, e.g. surface loop basis; no special search algorithm is needed. Stable in convergence of iterative solvers even with the existence of a null space
RWG Basis Loop Basis
Volume Loop Basis
0.25
0.1
0.1
Ra m
Rb m
h m
Example:
Volume Loop Basis
Incident Wave: 1 GHz, –z to +z
Relative permittivity: 4.0
No of tetrahedrons: 3331
No of RWG basis: 7356 (11.5)
No of loop basis: 4965 (10.05)
Basis reduction: 32.5%
No of iterations:
RWG: 159; Loop: 390
Bistatic RCS:
Full-Band MLFMAIncident Wave: 1 MHz
θ = 45deg, Φ = 45deg
No of triangles: 487,354
No of unknowns: 731,031
7 x 7 fork structure
0 50 100 150 200 250 300 350-70
-60
-50
-40
-30
-20
-10
0
10
20
(degrees)
Bis
tatic R
CS
(dB
sm
)
XY
Z
O
t d
a
a=0.1 ma=0.1 md=3 md=3 mt=0.173 mt=0.173 mf=1.0 GHzf=1.0 GHz
Novel Nystrom Method
Scattering by a pencil target:
0 20 40 60 80 100 120 140 160 180-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
(degrees)
Monosta
tic R
CS
(dB
sm
)
HH
VV
XY
Z
O
d
a
a=1 inchd=5 inchsf=1.18 GHz
Scattering by an ogive:
Novel Nystrom Method
0 20 40 60 80 100 120 140 160 180-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
(degrees)
Bis
tatic R
CS
(dB
)
Nystrom
MoM
Scattering by a very thin diamond:
02.0
4.0
h
a
XX
YY
ZZ
OOhh
aa aa
Novel Nystrom Method
101
10-3
10-2
10-1
100
101
Unknowns per wavelength
RM
S E
rror
(dB
)
HH, rule1
HH, rule2
HH, rule3VV, rule1
VV, rule2
VV, rule3
Higher-order convergence for ogive scattering:
Novel Nystrom Method
101
10-2
10-1
100
101
Unknowns per wavelength
RM
S E
rror
(dB
)
HH, rule1
HH, rule2
HH, rule3VV, rule1
VV, rule2
VV, rule3
Higher-order convergence for pencil scattering:
Novel Nystrom Method
Conclusion
FEM & ROM modeling of multilayer, distributed feed network (Cangellaris) Accurate, broadband antenna/array modeling with frequency- and time-
domain FEM (Jin) Linear/nonlinear feeds, cable feeds, antenna/platform interaction, &
TDIE/ROM integration (Michielssen) Full-band MLFMA, loop-basis for VIE, and higher-order Nystrom method
(Chew)
Past progresses:
Future work: Hybridization of FEM and ROM to interface antenna feeds
and feed network Hybridization of FEM and TDIE (TD-AIM & PWTD) or MLFMA
to model antenna/platform interaction Parallelization to increase modeling capability