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Northwest Electromagnetics & Acoustics Research Laboratory
Dr. Lisa Zurk, Director
http://nearlab.ece.pdx.edu/
The NEAR-Lab focus is on the modeling and analysis of
electromagnetic and acoustic wave phenomenon for development
of advanced signal processing techniques. The understanding of
wave scattering provides a basis to devise and evaluate advanced NEAR-Lab
signal processing algorithms for applications such as radar, sonar,
and biomedical imaging.
Electromagnetics Research Projects: Comparison of Synthetic Aperture Radar
(SAR) image with optical image (SAR image
• Scattering models for Synthetic Aperture Radar is from the MIT Lincoln Multi-mission ISR
Testbed, LiMIT)
• Correlation processing for detection of land mines
• Rough surface scattering from target multipath
• Terahertz imaging for explosive detection and biomedical imaging
Comparison of NEAR-Lab rough Radar multipath modeling
surface scattering codes (collaboration with MIT)
Direct Target-Ground
e ik ( 2 r r )
eik ( 2 r ) r ( r r )
r2
Ground-Target Ground-Target-
Ground Scattering models for correlation processing applied to radar
ik ( 2 r r ) ik 2 ( r r )
e e
r ( r r ) ( r r ) 2 detection of land mines; exploits structure of signature from
buried object (collaboration with Dr Timchenko, Inst. RadioPhys.,
Ukraine)
Research Spotlight: Terahertz Imaging
Until recently, little was known about properties of the terahertz region (terahertz = 1012, between microwave and visible) of
the electromagnetic spectrum, earning it the title of the “THz Gap”. However, recent advances in ultrafast optics have
provided the means to generate and measure THz signals, and this has opened the possibility of THz sensing with a
multitude of potential applications. Two of the most promising – detection of explosive materials and biomedical imaging –
are being actively explored in the Northwest Electromagnetics and Acoustics Research Laboratory (NEAR-Lab). The
research is supported by grants from the Office of Naval Research (ONR) and the National Science Foundation (NSF), and is
in collaboration with the Applied Physics Laboratory at the University of Washington.
Selected NEAR-Lab Electromagnetics
Publications & Presentations:
L.M. Zurk, “Scattering in Random Media Applied to Terahertz Time
Domain Spectroscopy”, (invited presentation), Progress in
Electromagnetic Research Sym. (PIERS), Beijing, China, Mar. 2007
L.M. Zurk, B. Orlowski, G. Sundberg, D.P Winebrenner, E.I Thorsos,
A. Chen, “Electromagnetic Scattering Calculations for Terahertz
Sensing”, Proc. of SPIE, San Jose, CA, Jan. 2007
HMX explosive granular structure Coupled grain scattering: random L.M. Zurk1, B. Jouni, F. Farahbakhshian, D.P. Winebrenner, E.I.
(image from LLNL UCRL-PRES- media models (“Swiss cheese” model) Thorsos, A. Chen, M. R. Leahy-Hoppa, L.M. Hayden, “Scattering
150298) Calculations for Evaluation of Terahertz Detection of Explosive
Data and model comparison showing experimental scattering by Material”, Seventh International Symposium on Technology and the
Large Grain PE (LGPE) versus Small Grain PE (SGPE) explained Mine Problem (MINWARA), Monterey, CA, May 2006
well with dense media theory, Quasi-crystalline approximation (QCA) R. Toengi, “Airborne Synthetic Aperture Radar (SAR) Terrain-Based
Processing”, MS Thesis
(Data provided by University of Maryland, Baltimore County)
L. M. Zurk, S. Matzner, F. Farahbakhshian, R. Toengi,
"Electromagenetic Modelling for Interpretation of Airborne SAR
Reference
Imagery," PIERS, Cambridge, MA, March 2006.
SGPE (data)
2
10 LGPE (data) L. M. Zurk, B. Jouni, F. Farahbakhshian, "Calculation of Scattering
SGPE (QCA)
LGPE (QCA) from Polyethylene Particles Compared with Terahertz
Measurements," PIERS, Cambridge, MA, March 2006.
Relative Spectral Level
S. Matzner, L. M. Zurk, A. I. Timchenko, "Radar Detection of
1
10 Subsurface Objects Using Correlation Imaging," PIERS, Cambridge,
MA, March 2006.
A. I. Timchenko, L. M. Zurk, "Signal Processing Methods for
Detection of Subsurface Objects by Ultra-wideband SAR," IEEE
0
10 GRS, Korea, July 2005.
0 2 4 6 8 10
Frequency (THz)
NEAR-Lab Research involves numerical modeling, development of theory,
and participation in large-scale collaborative experimentation efforts
Northwest Electromagnetics & Acoustics Research Laboratory
Dr. Lisa Zurk, Director
http://nearlab.ece.pdx.edu/
The NEAR-Lab focus is on the modeling and analysis of
electromagnetic and acoustic wave phenomenon for
development of advanced signal processing techniques. The NEAR-Lab
understanding of wave scattering provides a basis to devise and
Bathmetry map of Half Moon Caye,
evaluate advanced signal processing algorithms for
Belize, from sonar echo-sounding
applications such as radar, sonar, and biomedical imaging. Fish
data (collaboration with the Nature
aggregation &
spawning Conservancy)
Acoustics Research Projects:
• Physics-based processing for active sonar networks
• Acoustic propagation into ocean bottom sediments Echogram
• Sonar mapping of coral reefs and fish aggregation
• Array processing of passive sonar systems Spectrogram(Data) Spectrogram(Simulation) Range vs time
-10 -5
Data from Malta
Active sonar geometry, with 20 20 20
normal mode propagation Plateau (Italy) 40 40 40
-10
effects for acoustic energy Acoustic Target showing observed 60 -15 60 60
source striation patterns,
Time(min)
80 80 80
dB
Time/frequency spectra and excellent 100 100
-15
100
agreement with 120
-20
120 120
Bottom
reverberation NEAR-Lab model 140 140
-20
140
predictions. 160 160 160
-25 -25
450 500 550 450 500 550 16 18 20 22 24 26
Frequency(Hz) Frequency(Hz) Range(km)
Research Spotlight: Ocean Bottom Profiling
There are a number of applications – such as marine habitat monitoring, mine detection, and Navy sonar operation - in which the profile
of the ocean bottom is required. However, this information is generally difficult to obtain and prone to inaccuracy. One promising
approach is to use a broadband sonar pulse (for example, a chirp signal) that can penetrate into the bottom, and then measure the time-
frequency content of the reflected energy. Theoretically, this signal contains information on the acoustic properties of all the layers, but
interpretation of this information is difficult due to scattering from ocean layers and buried inhomogeneities (for example, shells and
rocks). Research in the Northwest Electromagnetics and Acoustics Research Laboratory (NEAR-Lab) is helping address this by
developing acoustic scattering models, and validating these models with data from the Navy’s Shallow Water 2006 experiment. This is in
collaboration with Applied Physics Laboratory, University of Washington and the Naval Research Laboratory (NRL).
Incident acoustic Specular reflection
Acoustic scattering can occur due to
wave
multiple phenomenon: specular
Selected NEAR-Lab Acoustics Publications &
reflection, rough surface scattering, Presentations:
Rough surface
volume scattering, and layer scattering.
c0 , 0
L.M. Zurk, J. Quijano, M. Velankar, D. Rouseff, “Bistatic invariance
for active sonar systems”, Acoustical Society of America (ASA),
c1 , 1
Volume scattering Chirp sonar Honolulu, HI, Jan 2007
Layer scattering c2 , 2 experiment
L.M. Zurk, J. Lotz, T. Ellis, J. McNames, J. Ecochard, “Sonar mapping
c3 , 3 Bottom layer 1 for coral reef conservation”, ASA, HI, 2007
Bottom layer 2
Bottom layer n J. Quijano, L.M. Zurk, A. Turgut, D.J. Tang, “Ocean bottom scattering:
characterization with chirp sonar”, ASA, HI, 2007
The Navy-sponsored Shallow Water 2006 (SW06) experiment took
L. M. Zurk, D. Rouseff, G. Greenwood, "Bistatic Invariance Principle
place in August on the New Jersey shelf. PSU student Jorge Quijano for Active Sonar Geometries," European Conference on Underwater
participated in the experiment on the Research Vessel Knorr (owned Acoustics (ECUA), Carvoviero, Portugal, June 2006
by MIT Woods Hole) and in collaboration with APL/UW and NRL. J. Quijano, Use of the Invariance Principle for Target Tracking in
Jorge was responsible for taking Conductivity- Temperature-Depth Active Sonar Geometries”, MS Thesis
(CTD) measurements during the experiment, and will be using the J. Quijano, L.M. Zurk, “Use of the invariance principle for target
chirp sonar data as part of his PhD dissertation. tracking in active sonar geometries”, IEEE Oceans, Providence, RI,
2006
0 L. M. Zurk, B. H. Tracey, "Depth-shifting of guide sources," Oct 2005,
Jorge on
RV Knorr JASA, N118 (4).
5
L. M. Zurk, "Guide Source Depth and Range Translation for Robert
10 MFP," ASA, Minneapolis, October 2005
Depth(m)
15 M. R. Velankar, L. M. Zurk, "Mode-Based Adaptive processing in
uncertain environments," ASA, Minneapolis, October 2005
20
L. M. Zurk, M. R. Velankar, "Passive Sonar Array Sub-space
25 Processing based on Modal Decomposition," IEEE Oceans,
Washington DC, October 2005.
30 Chirp sonar from SW06 (courtesy of NRL)
L. M. Zurk, "Performance of Mode-based Processing in Presence of
1000 2000 3000 4000 5000
Ping number Environmental Uncertainty," ASA, Vancouver, Canada, May 2005.
NEAR-Lab Research involves numerical modeling, development of theory,
and participation in large-scale collaborative experimentation efforts
