CHAMPAIGN, Ill. -- Scientists at the Center for Computational Electromagnetics at the University of Illinois recently set a world record by calculating the radar cross-section of an aircraft -- a measure of how visible the aircraft is to radar -- at a microwave frequency of two gigahertz.
The numerical simulation -- which involved solving for nearly 2 million unknowns -- was performed using newly developed software called the Fast Illinois Solver Code. The program was run on the Silicon Graphics CRAY Origin2000 computer at the U. of I.'s National Center for Supercomputing Applications.
"The radar cross-section of an aircraft can be used for target detection and identification purposes," said Weng Chew, a U. of I. professor of electrical and computer engineering and director of the computational electromagnetics center. "The calculation of the radar cross-section of an aircraft above one GHz -- the old record -- has been viewed as the Holy Grail in computational electromagnetics."
To calculate the scattering solution, Chew and colleagues Jiming Song and Caicheng Lu (visiting professors of electrical and computer engineering) developed a sophisticated algorithm based on the fast multipole method first proposed by Vladimir Rokhlin of Yale University. Chew's group helped pioneer the method and became the first group to successfully use it for complex three-dimensional electromagnetic scattering problems.
"Because the number of unknowns in a scattering solution is proportional to both the size of the aircraft and the radar frequency, the number of computations becomes extremely large as the frequency increases," Chew said. "By combining the algorithm with a special mathematical structuring of the scattering solution, both the computer time and the memory requirement can be significantly reduced."
Earlier this year, Chew and his colleagues collaborated with DEMACO, a software development company, to release Version 1.0 of the Fast Illinois Solver Code. "The company added a graphical user interface and various geometry-handling capabilities," Chew said. "As a result, the code is very user friendly -- even users with little or no electromagnetics background can calculate the radar cross-section of complex targets such as large aircraft."
In addition to calculating radar cross-sections, the new software also can be used to help design computer chips, telecommunications systems and micro-electromechanical sensors, Chew said. "Computational electromagnetics is becoming increasingly important in modern technology because it can replace many expensive experiments with less costly computer simulations."
The Center for Computational Electromagnetics is supported, in part, by the Air Force Office of Scientific Research.