GTD scattering analysis add-on

The Multi GTD is a GRASP add-on developed and designed to perform GTD analysis of  large and complex reflectors and constructions.  It uses a highly advanced ray-tracing approach to efficiently identify the possible ray paths in a given system, a task which is usually the most complicated part of a general scattering analysis problem. The GTD field analysis is performed using the most accurate uniform GTD formulation. The Multi GTD add-on is used for a number of complex spacecraft antenna farm problems, most noticably on the European Space Agency's scientific Planck mission.

For final analysis of spacecraft antennas it is often necessary to include influences from other parts of the structure, such as the satellite body, solar panels, experiment boxes etc. By using the Multi GTD add-on with its automatic calculation of the ray combinations will ensure an accurate analysis.

The Multi GTD adds various advantages when dealing with millimetre wave frequencies. The size of the reflectors, as well as other structure elements, may be thousands of wavelengths making the physical optics approach impossible to employ in practice. In addition, scanned or shaped antenna systems may suffer from blockage of the main beam which can be  difficult to determine by simple visual inspection. In this case, the accurate and reliable GTD software comes perfect in hand.