Modeling Offset-Fed TE Reflectarrays for Far-Field Pattern Prediction at Upper mm-Wave Frequencies

Predicting the far-field radiation pattern of reflectarrays (RAs) by means of semi-analytical models is of great interest to save computationally expensive full-wave simulations, especially when performing parametric optimization of large-scale or distributed arrays. This work presents a novel approach for modeling the far-field response of an RA, which is obliquely illuminated by a planar TE wave and performs beam steering within the incidence plane. In particular, the model predicts specular reflections of RA and carrier in offset-fed scenarios. The proposed method supplements the conventional array theory; it only requires full-wave simulation of the UC’s phase characteristic and a single array row, allowing to scale up to larger array sizes by analytical means. For demonstration, several RAs implemented on thin fused silica substrates are characterized at 245 GHz, where the measured far-field patterns agree very well with both the full-wave simulation and the analytical prediction.