Content uploaded by Assaf Levanon
Author content
All content in this area was uploaded by Assaf Levanon on Mar 15, 2015
Content may be subject to copyright.
Content uploaded by Assaf Levanon
Author content
All content in this area was uploaded by Assaf Levanon on Mar 15, 2015
Content may be subject to copyright.
Abstract— Demonstration of Millimeter Wave (MMW)
imaging system using chirp radar method and Glow Discharge
Detector (GDD) Focal Plane Array (FPA) is presented. A unique
quasi optical set up and advanced detection methods using the
GDD are intended to build the 3D MMW imaging system. This
quasi optical setup enables to detect the distance and reflection of
each point in object in order to reconstruct a 3D MMW image.
Keywords —Millimeter wave radiation, quasi-optical design,
Millimeter wave detector, Glow Discharge Detector (GDD),
Plasma, Radar.
I. INTRODUCTION
3D millimeter wave imaging using RADAR principles and
GDD is a new concept which has diverse application in home
land security, medicine, and industry. 3D Imaging systems
based on conventional FMCW radars in MMW regime were
demonstrated and published in [1, 2]. Those systems are based
on scanning mechanisms and thus it takes a long time to
obtain an image [1, 2]. Furthermore those systems employ
very expensive MMW components such as detectors, mixers,
LNA’s, antennas and quasi-optics [3]. In this work we propose
a new approach for 3D MMW imaging based on radar
principle and very inexpensive sensor named GDD. The GDD
has proven to be an excellent THz detector [4]. It shows a very
good responsivity and it can operate as heterodyne detector
[5]. Furthermore, The GDD is room temperature and is very
rigid [4]. In order to enable real time operation of the imaging
system, a focal plane array using GDD pixels is required. This
array enables to detect the distance and magnitude of each
GDD pixel in the FPA simultaneously. Our previous
experimental work demonstrated the feasibility of a very
inexpensive W-band chirp/FMCW radar system using GDDs
[6].
II. QUASI OPTIC DESIGN OF MMW 3-D IMAGING SYSTEM
BASED ON GDD FPA
The full quasi-optic concept design of an MMW 3D imaging
system using a GDD FPA is shown in Fig. 1. In this design the
projected system is used to generate a collimated beam using
an on axis Parabolic Mirror (PM) that illuminate the target
(this is instead of a focused beam used in ordinary scanning
based FMCW radar systems [7]). A beam splitter is used here
to generate the reference beam which is directed to the GDD
FPA by a plane mirror. A spherical imaging mirror is used to
image the target object on the GDD FPA, placed in the image
plane. Heterodyne detection is carried out by each GDD in the
FPA, creating a beat frequency. This beat frequency is
proportional to the optical path difference of the two beams
(reference and reflected). Pixel intensity is an indication of
object brightness, and pixel beat frequency is an indication of
object range from the GDD pixel. Using computer software a
topographic map of the object can be obtained. Hence, we can
create a 3D MMW image.
The Quasi optic design shown in figure 1 was design,
manufactured and realized. In this work an experimental
demonstration of this quasi optical set up is demonstrated.
Figure1: Quasi optic design of MMW 3-D imaging system based on GDD
FPA.
III. SIMULATION OF THE QUASI OPTICAL SYSTEM
In order to simulate the performance of the system presented
in figure 1. We performed a Zemax simulation of an "F" shape
3D Millimeter wave imaging system using chirp
radar and Glow Discharge Detector pixel
D. Rozban, A. Aharon (Akram), A. Levanon, A. Abramovich, N. S. Kopeika
978-1-4673-5756-2/13/$31.00 ©2013 IEEE. From the 2013 IEEE International Conference on Microwaves,
Communications, Antennas and Electronic Systems (COMCAS 2013), Tel Aviv, Israel, 21-23 October 2013.
object. In this simulation the projection mirror of Fig. 1
illuminate an F shape object while the imaging mirror images
its image on the FPA. The projection system was simulated by
CST microwave studio simulation code.
The object is located at a distance of 10 meters from the
projection mirror and the image received is given in Fig. 2.
Figure 2: Image Simulation of metal "F" shape object: including diffraction
aberrations in the top and including geometric aberrations in the bottom.
IV. STAND-OFF DETECTION USING GLOW DISCHARGE
DETECTOR IN MMW BAND
In order to confirm the system performance a MMW one pixel
detection of a metal object from a distance of about 10 meters
is demonstrated using the set up of figure 3. In this experiment
the radiation is amplitude modulated with a 100 KHz square
wave. This experiment demonstrates the performance of the
projection mirror, and the GDD ability to detect MMW signals
from distances of about 10 meters.
The modulation signal (upper line) and detection signals
(lower line) received on scope are given in Fig 4. As seen in
Fig 4, the detection signal of one pixel is clearly seen. This
result indicates the feasibility of imaging objects form
distances of 10 m using focal plane array compose of glow
discharge detectors.
Figure 3:One pixel detection from distance of 10 meters
Figure 4: modulation signal (upper line) and detection signal (lower line)
received on scope using the experimental setup of Fig. 3.
V. CONCLUSIONS AND FUTURE PLAN
The result given here indicates that real time 3D MMW
imaging system is achievable. Our future plans include the
design of a FPA of detectors intended for the detection of
FMCW signals. Using this GDD FPA with the setup given in
Fig. 1 should produce the ability of obtaining 3D MMW
images.
ACKNOWLEDGMENTS
The authors are grateful for the support of the Office of
Naval Research and the US Army Night Vision and Electronic
Sensors Directorate. They also appreciate the support of the
Institute for Future defense Technologies research named for
the Medvedi, Schwartzman, and Gensler Families.
REFERENCES
[1] G. L. Charvat, “A unique approach to frequency-modulated continuous
wave radar design,” M.S. thesis, Univ. Michigan Press, East Lansing,
MI, 2003.
[2] G. L. Charvat, “Synthetic aperture radar imaging using a unique
approach to frequency-modulated continuous-wave radar design,”
Antennas Propag. Mag., vol. 48, no. 1, pp. 171–177, Feb. 2006.
[3] C. A. Weg, W. von Spiegel, R. Henneberger, R. Zimmermann, T.
Loeffler, and H. G. Roskos, “Fast active THz cameras with ranging
capabilities,” J. Infrared, Millim. Terahertz Waves, vol. 30, no. 12, pp.
1281–1296, Dec. 2009.
[4] A. Abramovich, N. S. Kopeika, D. Rozban, and E. Farber, “Inexpensive
detector for terahertz imaging,” Appl. Opt., vol. 46, no. 29, pp. 7207–
7211, Oct. 2007.
[5] H. Joseph, A. Abramovich, N. S. Kopeika, and A. Akram, “Heterodyne
detection by miniature neon indicator lamp glow discharge detectors,”
IEEE Sensors J., vol. 11, no. 9, pp. 1879–1884, Sep. 2011.
[6] D. Rozban, A. Akram, A. Levanon, A. Abramovich, N. S. Kopeika " W-
Band Chirp Radar Mock-Up Using a Glow Discharge Detector" IEEE
Sensors J., vol. 13, no. 1, pp. 139–145, Jan. 2013.
[7] G. Chattopadhyay, K. B. Cooper, R. Dengler, T. E. Bryllert, E. Schlecht,
A. Skalare, I. Mehdi, and P. H. Siege, “A 600 GHz imaging radar for
contraband detection,” in Proc. 19th Int. Symp. Space Terahertz
Technol., Apr. 2008, p. 300.
