A 2 bit Circularly Polarized Reconfigurable Reflectarray Using p-i-n-Diode-Tuned Crossed-Bowtie Patch Elements

A wideband, wide-scanning-angle, and high-efficiency 2 bit circularly polarized (CP) reconfigurable reflectarray (RRA) is presented for 2-D dynamic beam control. The reflectarray is achieved using tunable elements based on crossed-bowtie patches with annually distributed p-i-n diode loadings. By squeezing two interlaced crossed-bowtie patches into a single unit-cell and making them strongly coupled, doubled phase state and drastically extended element bandwidth are simultaneously obtained. In addition, simple biasing circuitry and low-loss reconfigurable mechanism are also introduced. The fabricated 16 x 16 2-D beam-scanning reflectarray working at X-band demonstrates experimentally a 3 dB gain and axial ratio (AR) bandwidth of 22%, a peak gain of 24.5 dBic, an aperture efficiency of 35%, sidelobe levels of around -20 dB, and a scanning range up to +/- 60 degrees. With such well-rounded performances, the proposed reflectarray design, which realizes 2-D CP beam scanning, can be a competitive candidate for space and satellite communications.