TY - JOUR
T1 - A quantitative study of Luneberg-lens reflectors
AU - Liang, Charles S.
AU - Streater, Donald A.
AU - Jin, Jian Ming
AU - Dunn, Eric
AU - Rozendal, Timothy
N1 - Funding Information:
Dr. Jin is a member of Commission B of USNCAJRSI and of Tau Beta Pi, and was elected a Fellow of the IEEE in 2001. He was a recipient of the 1994 National Science Foundation Young Investigator Award and the 1995 Office of Naval Research Young Investigator Award. He also received the 1997 Xerox Junior Research Award and the 2000 Xerox Senior Research Award, presented by the College of Engineering, University of Illinois at Urbana-Champaign. He was appointed the first Henry Magnuski Outstanding Young Scholar in the Department of Electrical and Computer Engineering in 1998. He was appointed a Distinguished Visiting Professor at the Air Force Research Laboratoryin 1999, and was awarded Adjunct or Guest Professorships by City University of Hong Kong, Anhui University, Peking University, South-east University, and Nanjing University. He served as an Associate Editor of the IEEE Transactions on Antennas and Propagation and of Radio Science, and is also on the Editorial Board for Electro-
PY - 2005/4
Y1 - 2005/4
N2 - Luneberg-lens reflectors, which provide passive wideband and wide-angle radar-signature augmentation, have been widely used in small military target drones, decoys, and marine vessels. Due to the difficulty of fabricating inhomogeneous dielectrics with a continuously varying index, Luneberg lenses are usually constructed with multilayered step-index dielectrics. This paper presents a quantitative study of a practical design of a three-layer Luneberg-lens reflector for C- and X-band operations. Extensive wideband and wide-angle measurements were carried out for this lens with three different cap reflectors, as well as for the lens alone without any reflector. A comprehensive numerical analysis, using the Finite-Element Method combined with boundary integral equations, was also conducted. This was done to support the measured data and to provide additional insight for a better understanding of the performance and the limitations of the Luneberg-lens reflector than could be achieved with the traditional ray-optics method. The effect of reflector size is discussed, and the limitation of three-layer design is demonstrated. It has also been shown that very accurate material parameters must be ascertained so as to achieve the level of accuracy commonly desired in the computational electromagnetics codes applied to inhomogeneous dielectrics. The excellent agreement between the numerical and measured data indicates that this full-wave Maxwell solver can be used to explore the design limits and optimize designs for this type of lens reflector.
AB - Luneberg-lens reflectors, which provide passive wideband and wide-angle radar-signature augmentation, have been widely used in small military target drones, decoys, and marine vessels. Due to the difficulty of fabricating inhomogeneous dielectrics with a continuously varying index, Luneberg lenses are usually constructed with multilayered step-index dielectrics. This paper presents a quantitative study of a practical design of a three-layer Luneberg-lens reflector for C- and X-band operations. Extensive wideband and wide-angle measurements were carried out for this lens with three different cap reflectors, as well as for the lens alone without any reflector. A comprehensive numerical analysis, using the Finite-Element Method combined with boundary integral equations, was also conducted. This was done to support the measured data and to provide additional insight for a better understanding of the performance and the limitations of the Luneberg-lens reflector than could be achieved with the traditional ray-optics method. The effect of reflector size is discussed, and the limitation of three-layer design is demonstrated. It has also been shown that very accurate material parameters must be ascertained so as to achieve the level of accuracy commonly desired in the computational electromagnetics codes applied to inhomogeneous dielectrics. The excellent agreement between the numerical and measured data indicates that this full-wave Maxwell solver can be used to explore the design limits and optimize designs for this type of lens reflector.
KW - Antenna measurements
KW - Electromagnetic scattering
KW - Electromagnetic scattering by nonhomogeneous media
KW - Lens antennas
KW - Luneberg lens
KW - Numerical analysis
KW - Radar cross sections
KW - Reflector antennas
KW - Scattering parameters measurements
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U2 - 10.1109/MAP.2005.1487776
DO - 10.1109/MAP.2005.1487776
M3 - Article
AN - SCOPUS:23044484602
SN - 1045-9243
VL - 47
SP - 30
EP - 42
JO - IEEE Antennas and Propagation Magazine
JF - IEEE Antennas and Propagation Magazine
IS - 2
ER -