Determination of the Offset Distance for F-MARS: An Equivalent Source Model Perspective

In many cases, reflections within antenna measurements are the primary factor contributing to the far-field antenna test. The technique named far-field Mathematical Absorber Reflection Suppression (F-MARS) has been successfully used to identify and suppress the effects of range multi-path effects in antenna testing. While the existing studies have illustrated the effectiveness of the F-MARS technique, the exact value of the offset distance not been elucidated in detail. We present a method to determine the offset distance of F-MARS in this letter. The proposed method incorporates the equivalent source model for vector decomposition of multipath signals, reveals the essence of the separation effect achieved by F-MARS, and deduces an offset distance expression including the interference angle, aperture and other variables. Numerical simulation and experimental results prove the rationality of the offset distance obtained by the proposed method, and show its guiding significance for F-MARS.