RF Sensor Performance in Electrically Large, Complex Environments

The radiation from antennas mounted on a geometrically complex platform, such as an aircraft, remains a challenging electromagnetics problem. Since military applications often require multiple antennas on the same platform, the analysis of interference is also important. It is difficult to use full wave electromagnetic solutions for such problems at high frequencies due to computer memory and computation time required. The best alternative is to use full wave methods only to analyze the antenna radiation characteristics, and to use the Geometrical Theory of Diffraction (GTD) to predict how energy propagates over the electrically large platform. A key advantage of GTD over other high frequency asymptotic methods is the accuracy with which it can model propagation along curved surfaces by means of surface diffracted rays, or creeping waves. The GTD also has the ability to combine creeping waves with diffractions and reflections from other features, such as the wings and stabilizers on aircraft. Another important is the memory and computation time does not increase with frequency, since the time to find the ray paths depends only on the complexity of the geometry not on the electrical size.