Ka-band Mechanically Beam Scanning Bifocal Reflectarray Antenna with Optimized Phase Distribution

A bifocal reflectarray antenna is proposed for mechanically beam scanning applications at Ka-band. Unlike the conventional bifocal method based on the average phase distributions of the bi-focus, an optimized phase distribution function is proposed to improve the beam scanning range and gain performance. Based on the analysis of illuminated power from feeding horn, the weighting functions can he selected. Three reflectarray prototypes based on the in onofocal method, conventional bifocal method, and the proposed technique, are compared to validate the proposed method. The measurements of proposed prototype show a 60 degrees scan coverage with the gain ranging from 29.82-32.08 dBi at 35 Gib and an 18% 3-dB gain bandwidth at each beam direction.