A 10 240-Element Reconfigurable Reflectarray With Fast Steerable Monopulse Patterns

A large-scale 1-bit reconfigurable reflectarray with the feature of fast steerable monopulse patterns has been designed and tested at X-band. The reflectarray element integrates one PIN diode to reconfigure the reflective phase between 0° and 180°. The entire reflectarray is composed of 160 × 64 elements, with a total size of 2.56 m × 1.024 m. Critical design issues, including element modeling, subarray optimization, and feed horn selection, are investigated to achieve good radiation performance. For the purpose of realizing fast beam steering, 160 field-programmable gate arrays (FPGAs) are adopted to control “ON/OFF” states of every p-i-n diodes in parallel. Digital beam forming methods have been applied to scan both the sum and difference beams. The reflectarray has been fabricated and measured in an anechoic chamber, and a high gain (37.4 dBi) with relatively good aperture efficiency (17.1%) has been realized in such a large-aperture size. Precise monopulse beam steering within ±60° azimuth range has been achieved with the switching time of only 2 μs. This largeaperture reflectarray shows promising applications for tracking and detecting systems.