Design, Analysis and Measurements of Reflected Phased Array Microstrip Antennas at Ka-band, using Hollow Phasing

The key issue in the design of microstrip reflectarray antennas is the technique used to obtain the required phase shift in the field scattered by each clement. Many solutions have been proposed in the past. Stub loaded patches, patches of variable size and patches with variable rotation angles are currently the most popular techniques. This paper introduces a different technique. The approach is based on identical patches with holes of different size to change the resonant frequency. This gives in turn a change in the phase of the reradiated field and allows directing the main lobe of the radiation pattern off broadside. The analysis was carried out at 33.5 GHz, first on a single element and then extended to arrays of finite dimensions. Some arrays were built and measurements were carried out on these prototypes. There is good agreement between theoretical results and measurements