The key goals and objectives of the project

1
The key goals and objectives of the project

• To develop high fidelity physics-based models for
  the clutter and target (including their
  interactions) that would allow
• Phenomenological study of the problem under
  consideration. This includes sensitivity studies
  of sensors attributes for a number of clutter and
  target parameters to design the configuration of
  a multi-sensor system.
• To generate a large amount of synthetic data with
  exact statistical knowledge of target and clutter
  parameters for development and testing of
  detection and sensor management algorithms.
• To develop physics-based inversion algorithms

2
Summary of the important accomplishments to date

• Physics-based foliage model development
• Enhancement of an existing coherent foliage model
  to so that an observation point can be in the
  near-field of the scatterers.
• Enhancement of scattering model for broad leaves
  (a closed form solution for thin dielectric disks
  that is valid for all incidence angles and all
  frequencies.
• Modeling the Effects of multiple scattering for
  dense cluster of coniferous needles analytically
  using a method based on distorted Borne
  Approximation.
• An accurate modeling of wave attenuation rate in
  foliage based a renormalization approach.
• Target-Foliage interaction
• A full-wave FDTD model for simulation of
  scattering from targets (up to VHF). Interaction
  with foliage is accounted for using a novel
  approach based on a Huygens surface enclosing
  the target and the application of reciprocity.
• Development of a near-field GO-PO-PO approach to
  obtain scattering from foliage and target. This
  model accounts for the effects of interaction of
  foliage and target very efficiently and allows
  simulation of scattering at high frequencies. We
  are in the process of model implementation and
  validation.

3
Summary of the important accomplishments to date

• Experimental data extraction
• Analysis of a foliage penetration data collected
  by ARL at Ka-band to extract foliage attenuation
  and ground reflectivity.
• Applications of the Foliage model
• Synthetic data generation for extraction of field
  statistics as a function of aspect angle,
  frequency, and spatial variables.
• Demonstration of application of time reversal
  method for achieving super-resolution imaging and
  field focusing for secure communications.
• Inverse Models
• Application of frequency correlation function for
  estimation forest parameters. The application of
  this method is demonstrated for stepped frequency
  systems and can be used to extract foliage
  channel parameters. This will allow a first order
  correction for the effect of foliage on the
  target signature.
• Application of time-reversal approach. An
  iterative method is proposed. The forward model
  is examined, super-resolution is demonstrated.

4
Summary of the important accomplishments to date

• Physics-based model for urban environment
• A ray-tracing code specialized for indoor-outdoor
  wave propagation in urban environment with
  applications in target detection is developed.
• preliminary results are obtained for through-wall
  imaging using an array transceivers
• Model verification
• A scaled W-band system is being used.
• Exact numerical models
• Measurements

5
Physics-based foliage model development Closed
form solution for thin dielectric disks
New Model for Broad Leaves

• Two approximate solutions, Rayleigh-Gans VIPO
  are not valid for the entire region of interest
  like frequency, size, observation direction.

• New formulation for scattering from thin
  dielectric disk

• The normal component of the current is constant
  and is decoupled from the tangential components

Rayleigh-Gans current
6
Circular Dielectric Disk
Validation Comparison with MoM
Backscattering
Square Dielectric Disk
Forward scattering
7
Analytical Computation of Mean Field Using DBA
Physics-based foliage model development Modeling
the Effects of multiple scattering
A
r
L i (r)
?eff
Double Cone
L s (r)
B
?eff
Concave Cylinder

• Shape of dielectric block is a body of
  revolution determined by the shape of the
  cluster.
• Incident field is attenuated by the effective
  dielectric block during path Li(r?), then
  scattered by the local differential volume with
  effective permittivity.
• Effective permittivity is calculated based on
  dielectric mixing formula, inhomogeneous and
  anisotropic due to different needle density and
  prefered orientation.

8
DBA model Verification Using MoM Forward
Scattering
Shh
Svv

• Forward scattering of a needle cluster
  consisting of 96 needles versus incident angle
  ?i, averaged over the self-rotation angle.
• DBA compared with MoM (multiple scattering)
  simulation results lt 0.5 dB error in scattered
  power and lt 10o phase difference.

9
DBA model Verification Using MoM Bistatic
Pattern
Shh
Svv

• Bistatic scattering (normal incidence) of a
  needle cluster consisting of 96 needles versus
  scattered angle ?s, averaged over the
  self-rotation angle.
• DBA compared with MoM (multiple scattering)
  simulation results pattern and phase matched
  well for the main lobe.

10
Multiple Scattering Model Compared with Measured
Results
7dB

• Rayleigh-Gans approximation is invalid at MMW
  frequencies.
• Multiple scattering model improves the
  simulation result by 7 dB.

Note Multiple scattering simulation takes
1600s, about 30 faster than RG simulation
(2300s).
11
Physics-based foliage model development
Near-field Second Order Scattering
Objects are in the near field of each other
Apply Reaction Theorem
The incident field induces a current density
on the particle 1 in the absence of particle 2.
is the near-field scattered field from
particle 2 when it is excited by an
infinitesimal current source along at the
observation point.
is the first plus second order scattered
field from particle 1.
12
Validation using MoM for dl
Two circular disks
13
Physics-based foliage model development Accurate
modeling of wave attenuation in foliage based a
renormalization approach

• Experimental data indicates signal attenuation
  with distance shows a nonlinear behavior with
  distance
• Path loss is usually computed from Foldys
  approximation (single scattering, far-field
  approximation)
• Overestimation of attenuation rate
• Significant error over long distances
• Signal attenuation
• a - absorption
• b - scattering loss
• c scattering gain (multiple scattering)

14
Statistical WAve Propagation (SWAP) Model
A Hybrid Statistical and Wave Theory Approach 1-
Statistically homogeneous forest properties can
be used to localize the field computation.

• A forest environment can be divided into
  statistically identical blocks along the
  direction of wave propagation.
• Each block of the forest can be considered as an
  N-port network with similar statistical
  properties.
• Once the input-output relation is determined, it
  can be used in a network approach to find the
  forest channel path-loss.

15
SWAP Model
2- Decompose the received power into coherent and
incoherent components.
jth block
Rx

• Received field contains mean and fluctuation
  components, received power contains coherent and
  incoherent components.
• Coherent power comes from the mean field which is
  the incident wave attenuated by the effective
  forest medium (Foldys approximation).
• Incoherent power comes from the fluctuation
  field, which contains the contribution from
  scatterers within each block of forest (assuming
  the blocks are statistically independent).

16
SWAP Model
3- Determine the input-output relationship of a
typical block.
Input
Output
Elementary currents computed from fluctuating
fields
Field components computed from the coherent
forest scattering model for each pixel
A forest block made up of many statistical
fractal trees with random location

• Assuming spatially uncorrelated input for
  fluctuating fields and using Monte Carlo
  simulation find the output mean-field and
  standard deviation (fluctuating field)

• Repeat the same procedure for a plane wave
  illumination (mean-field incident)

17
Desired Statistical Parameters for Estimation

• Variation of fluctuation field
• Spatial Correlation function
• Foldys attenuation coefficient
• Input-output relationship transmission matrix

Assumption statistical properties of forest
depend on the forest itself, not of the
excitation, therefore planewave incidence is
chosen for simplicity.
Note the estimation is conducted within one
representative block of forest and the results
are reused for any blocks.
18
Computation of Incoherent Power

• Radiation from the output surface of the jth
  block is computed using the field equivalence
  principle. Only the fluctuating component is
  considered.

• Ground effect is taken into account by using
  image theory.

• Surface fluctuation field beyond the forest
  dimensions (i.e. the broadening effect) can be
  neglected.

19
SWAP Model Verification

• Comparison between numerical foliage model and
  SWAP model
• Frequency 0.5 GHz, Tree density 0.05/m2
• Observation point height 1.5m, distance from
  forest edge 1m

• SWAP model is reasonably accurate compared to the
  single scattering model.
• Dual-slope phenomenon is clearly observed from
  the SWAP model simulation result.

20
Simulation Results

• Different frequencies
• Tree density 0.05/m2, Forest range up to 500m
• Observation point height 1.5m, distance from
  forest edge 10 m

• Dual-slope phenomena are observed at all
  frequencies.
• The knee point occurs at shorter distance as f
  increases due to higher incoherent power.
• Attenuation rate of the mean field is increasing
  with f.
• Scattering power is increasing with f. Incoherent
  power tends to dominate the field after the knee
  point.

21
Simulation Results (III)

• Different Tree Densities
• Frequency 0.5GHz
• Observation point height 0.75m, distance from
  forest edge 10 m

• Dual-slope phenomena are observed at all tree
  densities.
• The knee point occurs at shorter distances as
  tree density increases.
• Higher tree density causes more attenuation
  effect on the coherent power but gains more
  incoherent power which dominates after the
  slope-turning point.

22
Proposed Approaches
Target-Foliage interaction

• Low frequencies (flt100 MHz) brute force
  Full-wave methods can be used (FDTD, FMM, FEM)
• Scattering from foliage can be ignored
• Mid-frequency range (100 MHzltflt1 GHz) Hybrid
  FDTD and single scattering forest code
• Near-field interaction between foliage and target
  are included.
• High frequency (fgt1GHZ) Hybrid PO and improved
  forest code
• Near-field interaction between foliage and target
  are included.
• Iterative PO for target

23
Hybrid FDTD/forest model

1. Using the coherent forest model, calculate the
   fields on an FDTD boundary given in the proximity
   of target.

2. Using FDTD, compute the scattered fields from
the target on the same grid.
24
Hybrid FDTD/forest model

• To calculate the effect of the forest on the
  scattered field, apply the reciprocity theorem.
• So source observation are exchanged.

Note Using this procedure, interaction between
forest target is inherently taken into account.
25
Validation of Hybrid Frequency/Time-Domain
Modeling
Validation A 2x2x2 FDTD mesh is used to model
free space within the forest (in the absence of
any vehicles). The same problem is solved by a
pure MoM code. Results of the two methods are in
excellent agreement.
A FDTD box around the observation point
(y)
2x2x2 FDTD mesh and electric field component that
is plotted in the figure on the right.
FDTD simulation parameters Dx Dy Dz 0.3
m Dt 0.314 nsec
26
Forest Response at Low Frequencies
Frequency 30MHz 100MHz 10 trees are
considered. Dielectric constants 21.7 i14.6
for branch 9.8
i1.7 for ground. Height of tree 15m, Diameter of
trunk 22cm. 45o Incidence angle.
Note Effect from trees is can be ignored.
27
Bistatic Scattering from HUMVEE
Discretized HUMVEE for FDTD Analysis
Note Scattering from target is much larger than
that from forest at low frequency band.
28
Preliminary Results
Current Distribution over the HUMVEE
29
High-frequency Model

• Calculate scattering from the target inside a
  forest using PO approximation
• Valid for targets large compared to l
• Valid near specular directions where scattering
  amplitude is large.
• Forest scattering at high frequencies is very
  significant, hence the target is illuminated from
  all directions.
• Independent of observation point there will be
  many specular contributions.
• Process
• Calculation of field distribution on the
  scatterer using the coherent forest model.
• Based on these calculated fields derive PO
  currents on the target.
• Apply the reciprocity theorem to calculate
  scattered field from the target that includes the
  effects of trees.

30
Hybrid Target/Foliage Model
Dimension of Computational Domain
80lX100lX100l Number of scatterers excuding
needles gt 50,000
Sensitivity analysis
Frequency 2GHz Number of Trees 10
Simulation Scenario
Incident direction
Z
Y
q
3 l
3l
f
X
Height 1m
31
Electric current on the plate for different
forest realization

• 37
• f 177

Realization 2
Realization 1
Realization 3
The electric current induced on the plate is
highly sensitive to the arrangement of
trees. Scattering from nearby trees is very
significant.
32
Calculation of backscattering Using Reciprocity
Elementary source at the excitation point
Field computation inside forest
Calculate induced current J2 on the scatterer
Scattered field at the excitation point
Apply reaction theorem
No need for computation of scattering from forest
33
Backscattering sensitivity to Azimuthal and
elevation angles
q37
q37
Clutter
Plate

• Backscatter
• from plate
• fluctuates more
• along the elevation angle than the
  azimuthal angle.
• Backscatter is sensitive to
• forest realization, elevation and azimuthal
  angles.

f
f
f177
f177
Clutter
Plate
q
q
34
Another Example 3D Box
For 3-D objects the lit and shadow area from all
scatterers in forest must be identified
POGO Approach PO current estimation GO
shadowing
Direct Wave
Shadow for reflected
Lit for direct
Reflected Wave
Shadow for direct
Lit for reflected
Direct is shadowed if
Ground Plane
35
GO-PO Simulation Results Simple object
Z
Freq 2 GHz 10 Pine trees

• 30 Degrees
• 0 Degrees

Y
3l
Two view of the box
3l
3l
Height 1m
X
Ground Plane
Note Direct Incident field has strong effect on
the level of current.
36
Backscattering plots versus elevation angle
Freq 2 GHz 10 Pine Trees f 0 Degrees
Note Level of backscattering from the box Is
comparable to that of the forest.
37
Complex Objects

• For complex objects GO-PO Solution becomes
  intractable
• Estimation of shadowing is difficult, the
  algorithm is very complex and becomes the
  bottleneck in the scattering computation
• For each forest scattere and for each observation
  point, shadowing should be estimated.

Incident wave
Shadow
Lit
Very complicated algorithm for an arbitrary
object.
38
Iterative PO Approach
Iterative near-field PO approach
Incident field
PO-PO estimation of shadowing
J1 is the estimated PO current everywhere on the
target. Second order PO will cancel the first
order PO in the shadow area.

• By applying the PO-PO solution
• The process of identifying shadow and lit areas
  is eliminated.
• The accuracy of scattering from target is
  improved (all
• second-order effects are accounted for).

39
Comparison of Hybrid Iterative PO with MoM
Frequency 2GHz
Note A very good agreement is achieved between
MoM and Hybrid GOPOPO.
EFIE Current (TE case)
Multiple Scattering
RCS
Shadowing
40
Number of Facets 325300 Spacing lt l/2 Frequency
2GHz
Caterpillar Tracks
Hull and Rear Skirt
Side Skirts
Turret Roof and Gun
41
Current Distribution For TE-Polarized Incident
wave
Note Hybrid GO-PO-PO Approach can take care of
the shadowing effect very accurately and accounts
for all near-field double-bounce effects on the
target.

• 0 Degrees
• q 30 Degrees

20l
86l
33l
42
Back Scattering of the Tank in Free Space

• Frequency 2 GHz
• Number of points 325300
• f 0

Note For each incidence angle, the run time is
about 18 hours on a P3 workstation.
Z
20l
X
86l
Z
20l
Y
33l
33l
43
Simulated RCS of the Tank in Free Space
Frequency 2 GHz
44
Scattering Model Verification Using Scaled-System
1GHz 100GHz Scaling factor 100
Ds/ D0 ls / l0
Scaled Buildings
3D CAD Drawing
45
Computer controlled 3-D Printer
Scaled City Block
W-Band Dielectric Measurement Setup
46
CAD Model
Scaled Model
6.5 cm
10.7 cm
28 cm

• Scaled model covered by aluminum
• Sims covered with silver paint

47
Measurement System
UoM Anechoic Chamber
Transmit Antenna
UoM 93-95GHz fully Polarimetric
Radar Coherent-on-receive Dynamic range 100
dB Noise equivalent RCS -30 dBsm
Scaled tank, used for radar measurement in the
anechoic chamber of Radiation Laboratory
48
Comparison of theory with measurement
RAW DATA
49

• Applications of the Foliage model
• Synthetic data generation

• Enhanced SAR Target Detection Methods
• Multi-incidence angle data
• Spotlight SAR
• SAR tomography

50
Sensitivity to elevation angle
For fixed f 177 the induced current on the
plate is plotted for 3 close q.
51
Backscattering for different elevation
azimuthal angles for 2 different realizations
f
f
q
q
f
f
q
q
Note Fluctuation along the elevation angle is
more than that along azimuthal angle.
52
Cross pol Comparison
Level of the xpol from the forest is about 10dB
more than that of the plate.
53
Applications of the Foliage model Time Reversal
Methods

• Time Reversal Methods (TRM) are essentially an
  application of reciprocity
• Using an array in random media and through the
  application of TRM the multipath is used as a
  focusing lens.

JE1,E11
JE2,E21
Receive/transmit array of N elements
JEN,EN1
Reciprocity states

If currents JEn at receiver n En1 then
Therefore is a real
quantity, fields add coherently at original
transmit point
54
Point to Point Communications
Point-to-point secure communication

• Array in the forest, observation point outside 60
  deg. from normal.
• The antenna is a 17-element array with 1l spacing
  and in cross configuration
• Simulation is done at 10 GHz
• TRM produces a beam with 0.5deg. beamwidth
• element spacing could be increased with no
  grating lobes

Array beam without foliage
55
TRM Array Sensitivity Analysis
?i 60o
? 55 to 65o
15m
11 observation point
6m
2m
Antenna elements
11 z-directed receiver dipoles are located at
every 5o from ? 55o to 65o Array is supposed
to focus at ? 60o. TRM procedure is applied to
analyze effects of array element spacing as well
as number of array elements on TRM focused beam.
56
TRM Array Sensitivity Analysis1? Element
Spacing
17 antennas
9, 17 and 33 array elements. One vertical two
horizontal antenna configurations.
33 antennas
9 antennas
Note More elements, more spatial pattern.
57
TRM Array Sensitivity Analysis2? Element
Spacing
17 antennas One vertical two horizontal
antenna configurations.
2? Element Spacing
1? Element Spacing
More gain
Note Performance is significantly affected by
antenna configuration.
58
Time Reversal Methods

• Preliminary study using the coherent foliage
  model
• Point-to-point secure communication using TRM
• Achieving super-resolution focusing through
  proper use of multi-path.

Region of influence
Region of influence
Transmit array
Highly scattering random medium
Only scatterers in the vicinity of Tx and Rx
influence focusing
59
TRM for Foliage Camouflaged Target Detection
Due to scattering and attenuation, wave phase
front is distorted. Conventional SARs point
spread function is smeared.
SAR track
Multi-path, attenuation, fading, etc.
Beam pattern is broaden or lost.

• Application of TRM using a recursive method in
  conjunction with a first-order channel estimation

60
SAR Simulation
Beam focusing inside foliage using time reversal
method
Assume a fictitious source

• Excite fictitious source on ground through forest
  (determine Greens function of medium)
• Complex conjugate reradiate the signal through
  foliage (using reciprocity theorem).
• ? Due to channel, fading, multipath, forest will
  act as a lens to focus energy at the fictitious
  source point.

61
SAR Simulation
1 Km
3 dB
62
SAR Simulation
Array Distribution for a Polarimetric SAR That
can Focus Inside the pine Forest
Amplitude distribution
Phase distribution
63
Inverse Models Iterative TRM
I(x,y) L S(u,t) S(u,t) L 1I(x,y)
Phase conjugate the array
Array distribution
Reprocess
This process may not converge
64
Inverse Models Simulated FCF of a Tree Stand
Magnitude
Phase
For Extraction of tree height, attenuation,
ground refelectivity, and volume scattering
65
Frequency Correlation Function
Frequency spacing 2 MHz Number of
realizations 50
Canopy
Ground-trunk
27m2H
66
Choose SAR Data Similar to Simulated Data
X-band SAR image (B500 MHz)
? Range
Tree canopy, ground, and noise floor (this
resembles the simulated data)
Azimuth ?
Ground only
Perform similar FCF analysis on these two
SAR patches
67
Through Wall Imaging Using Space-Time Focusing

• There is a great demand in imaging interior of a
  building remotely and identifying the signature
  of the targets inside
• Applications include urban search-and-rescue
  scenarios for
• Military applications (rescue operations, threat
  assessment, etc.)
• Counter terrorism
• Police search operations
• SWAT teams to resolve
• hostage situations.
• Earthquake rescue

68
Flowchart of Imaging Method

• Focusing the array on strong scatterers starting
  from exterior walls
• Use forward model
• fine tune the stucture

69
Analysis tool 3-D Ray-Tracing Algorithm
Shooting a new Ray from Transmitter
Forward Model
NO
NO
Finding intersection point between Ray and
Objects (Reflection or Diffraction)
YES
Rays Power ? Receivers Sensitivity
YES
Calculating Reflection, Transmission or
Diffraction coefficients and Path_Loss
Following generated Sub-Rays at intersection point
Checking Reception Conditions
70
Top view of Ray-Tracing Steps
Reflection, Transmission and Diffraction are
considered
71
3D Modeling of the Environment

• 3-D Modeling for the Object Ground profile
• Thickness of the Walls (for the buildings)
• Effective permitivity and Loss tangent of the
  Material
• Discretization of the Complex Objects to
  Canonical shapes

• Objects Type
• Impenetrable
• Penetrable Type I II
• w/ or w/o V-Edge Diffraction
• w/ or w/o H-Edge Diffraction

Transitivity and Reflectivity for Multi-Layer
Objects
Wall
72
Diffraction from Edges
UTD Diffraction Coefficient for Impedance
Wedges
reflection coefficients for 0 and n faces of the
wedge for vertical and horizontal polarization
and
Reference H. M. Sallabi and P. Vainikainen, VTC
2003, pp. 783-787
73
A Five Stories Building
Material ?r ?
Glass 6.2 0.01
Wood 4 0.001
Brick Wall 4.44 0.01
Plasterboard 2.11 1e-4
74
A typical Scenario
75
Coverage Inside the Building (B1)
76
A typical Scenario for Imaging
77
Simulation Results

• Simulation has been done at 2.3 GHz for Vertical
  polarization (Frequency range allocated by FCC
  for Through Wall sensing (TWS) is below 0.96 GHz
  or 3.1-10.6 GHz).
• Sensitivity Analysis Adding 20 pieces of
  furniture at random positions did not reduce
  focusing

78
Sensitivity to Number of Sensors
79
Angle of Arrival
80 transmitters
80 transmitters Lower threshold
80
Delay Profile, Time Focusing
80 transmitters
Lower threshold
81
Frequency Sweep
82
Plans for future

• Generation of multi-modal radar data (multi-look
  angle, multi-frequency, bistatic, multi-baseline
  interferometric, and tomographic) in close
  collaboration with signal processing and sensor
  management team

wideband X-band boom SAR

• Develop a reduced model (macro-model) for
  attenuation rate in foliage as a function of
  frequency, foliage density and propagation
  distance.
• Enhancement of foliage physics-based models
• Foliage Model verification
• Through a collaborative project with GD.

83
Plans for future

• The application of a scaled model and
  measurements at W-band
• Demonstration of recursive TRM for foliage
  covered target detection
• Improve the computational efficiency of iterative
  PO approach to handle large targets at high
  frequencies.
• Examine SAR tomography and time reversal
  scenarios for foliage-covered target detection.
• Physics-based model for urban scenarios for
  applications such as target detection inside
  buildings.

84
Publications

• Papers published in peer-reviewed journals
• Nashashibi, A., K. Sarabandi, S. Oveisgharan, and
  E. Burke, Millimeter-Wave Measurement of Foliage
  Attenuation and Ground Reflectivity of Tree
  Stands at Nadir Incidence, IEEE Transactions on
  Antennas Propagation, vol. 52, no. 5, pp.
  1211-1221, May 2004.
• Koh, I.S., F. Wang, and K. Sarabandi, Estimation
  of Coherent Field Attenuation Through Dense
  Foliage Including Multiple Scattering, IEEE
  Transactions on Geoscience and Remote Sensing,
  Vol. 41, No. 5, pp. 1132-1135, May 2003.
• Wang, F., and K. Sarabandi, An Enhanced
  Microwave and Millimeter-wave Foliage Propagation
  Model, IEEE Transactions on Antennas and
  Propagation, accepted for publication (Jan.
  2004).
• Manuscripts in review or submitted to
  peer-reviewed journals
• Wang, F., and K. Sarabandi, Accurate prediction
  of propagation path-loss in foliage using a
  renormalization method, IEEE Transactions on
  Antennas Propagation, submitted for publication
  (June 2004).
• Koh, I., and K. Sarabandi, A New Approximate
  Solution for Scattering by Thin Dielectric Disks
  of Arbitrary Size and Shape" IEEE Transactions on
  Antennas and Propagation, submitted for
  publication (Jan. 2004).
• Papers published in conference proceedings
  volumes
• Sarabandi, K., I. Koh, H. Mosallaei, Hybrid FDTD
  and Single Scattering Theory for Simulation of
  Scattering from Hard Targets Camouflaged Under
  Forest Canopy, Proceeding of URSI International
  Symposium on Electromagnetic Theory, Pisa, Italy,
  May 23-27, 2004. (invited)
• Koh, I., and K. Sarabandi, A New Uniform
  Solution for Scattering by Thin Dielectric
  Strips TM Wave Incidence, Proceeding IEEE
  International Antennas and Propagation URSI
  Symposium, Monterey, CA, June 20-26, 2004.

85
Publications (cont.)

• Dehmollaian, M., I. Koh, and K. Sarabandi,
  Simulation of Radar Scattering from Electrically
  Large Objects under Tree Canopies, Proceeding
  IEEE International Antennas and Propagation
  URSI Symposium, Monterey, CA, June 20-26, 2004.
• Koh, I., and K. Sarabandi, An approximate
  solution for scattering by thin dielectric
  objects, Proceeding IEEE International Antennas
  and Propagation URSI Symposium, Monterey, CA,
  June 20-26, 2004.
• Sarabandi, K., I. Koh and M. D. Casciato,
  Demonstration of Time Reversal Methods in a
  Multi-path Environment, Proceeding IEEE
  International Antennas and Propagation URSI
  Symposium, Monterey, CA, June 20-26, 2004.
• Aryanfar, F., and K. Sarabandi, Through Wall
  Imaging at Microwave Frequencies using Space-
  Time Focusing, Proceeding IEEE International
  Antennas and Propagation URSI Symposium,
  Monterey, CA, June 20-26, 2004.
• Wang, F., and K. Sarabandi, Long-distance wave
  propagation through forested environments,
  Proceeding National Radio Science Meeting
  (URSI), Boulder, Colorado, Jan. 5-8, 2004.
  (invited)
• Sarabandi, K., and A. Nashashibi, Phenomenology
  of Millimeter-wave Signal Propagation and
  Scattering for Detection of Targets Camouflaged
  Under Foliage, Proceeding IEEE International
  Geoscience and Remote Sensing Symposium,
  Toulouse, France, July 21-25, 2003.
• Aryanfar, F., and K. Sarabandi, Evaluation of a
  Wave Propagation Simulator Using a 95 GHz
  Transceiver System, Proceeding IEEE
  International Antennas and Propagation URSI
  Symposium, Columbus, OH, June 22-27, 2003.
• Wang, F., I. Koh, and K. Sarabandi, Theory and
  Measurements of Millimeter-wave Propagation
  Through Foliage, Proceeding IEEE International
  Antennas and Propagation URSI Symposium,
  Columbus, OH, June 22-27, 2003.
• Sarabandi, K., and A. Nashashibi, Detection of
  Hard Targets Camouflaged Under Foliage Using
  Millimeter-wave Radars, Proceeding IEEE
  International Antennas and Propagation URSI
  Symposium, Columbus, OH, June 22-27, 2003.

86
Publications (cont.)

• Yakubov, V. P., E.D. Telpukhovskiy, K. Sarabandi
  ,V. L. Mironov, and V. B. Kashkin Field
  Attenuation and Depolarization Measurement for
  Electromagnetic Waves for Propagation Through the
  Larch Forest Canopy, Proceeding IEEE
  International Geoscience and Remote Sensing
  Symposium, Toulouse, France, July 21-25, 2003.
• Telpukhovskiy, E.D., V. P. Yakubov, K. Sarabandi,
  V. L. Mironov, and V. M. Tsepelev, Wideband
  Radar Phenomenology of Forest Stands,
  Proceeding IEEE International Geoscience and
  Remote Sensing Symposium, Toulouse, France, July
  21-25, 2003.
• (5) published abstracts
• Sarabandi, K. Electromagnetic scattering model
  of foliage camouflaged targets, East-West
  Workshop on Advanced Techniques in
  Electromagnetics, Warsaw, Poland, May 20-21,
  2004. (invited)

87
Personnel Contributing on K. Sarabandis
sub-Project (03-04)

• Graduate Students
• Mojtaba Dehmolaian, 2nd year Ph.D., MURI GSRA
  Partially covered
• Travis Smith, 1st year Ph.D. student, EECS
  Fellowship/MURI GSRA
• Feinian Wang, 3rd year Ph.D., GSRA
• Farsid Aryanfar, 5th year Ph.D., GSRA
• Postdoctoral Fellows
• Il-Suek Koh (assistant professor at Inha
  University, S. Korea since April 2004)
• H. Mosallaie (area of expertise time-domain)
• A. Nashashibi (area of expertise, MMW radars)