How coarse is too coarse in electrically large reflectarray smart antennas?

Abstract

Millimeter wave (mm-wave) bands are becoming potentially attractive candidates for next generation communication systems. It is envisioned that high gain smart antennas will be one of the key enabling technologies for such systems. At mm-wave bands, where electrical size of an individual antenna becomes very small, the inclusion of a reconfigurable mechanism in the antenna becomes a great challenge due to real estate constraints. In these scenarios a designer has to decide on the number of bits in a phase shifter for antenna beam steering which will result in an optimum design. This contribution addresses the issue of phase quantization in mm-wave high gain reflectarray smart antennas to achieve an optimum performance. Implementing coarse phase quantization greatly reduces the complexity at mm-wave bands. A case study is presented to highlight the effects of coarse phase quantization using various numbers of bits

Design of a continuously tunable reflectarray element for 5G metrology in the k-band

“…To use more than one or even two bits is not practical for millimeter wave antennas because of the limited space. The necessary bias-T and electronic devices are difficult to fit in the size of the reflectarray element (Ahmad et al, 2017). Because of the few discrete steps and fabrication tolerances, phase errors occur.…”