A Detailed PO / PTD GRASP Simulation Model for Compensated Compact Range Analysis with Arbitrarily Shaped Serrations
Compensated compact ranges offer accurate testing techniques for large devices under test. The quiet zone field performance is affected by diffracted field components from the sub and main reflector edges even though they are equipped with serrations in order to reduce this effect. The size, shape, and alignment of the serrations have a strong influence on the range performance and are important design parameters. For performance estimation and optimization, detailed EM simulation models are required. Integral equation methods like the Method of Moments (MoM) with Multilevel Fast Multipole (MLFMM) acceleration promise accurate simulation results. However, the memory requirements limit simulations nowadays to lower frequencies due to the electrical size of the compact range reflectors. For example, the main reflector of Astrium’s Compensated Compact Range CCR 120/100 including serrations is 1860 λ by 1600 λ in size at 40 GHz. Asymptotic methods are suitable for objects of this size, however, the accuracy has to be investigated and is related to the degree of detail in the model.
A detailed simulation model based on the Physical Optics (PO) / Physical Theory of Diffraction (PTD) method is developed in GRASP. Each serration is realized as an individual scatterer and can thus be modeled with arbitrary shape and orientation. Different modeling techniques have been applied in order to realize an accurate simulation model with acceptable runtime. In this paper, the simulation model will be described in detail and a comparison of the quiet zone fields will be drawn with the MoM / MLFMM tool Feko as well as with quiet zone probing measurements.
Publication: Proceedings, AMTA 2013, 06-11 October 2013
Place: Columbus, Ohio