  Resonant optical phased arrays are a promising way to reach fully
reconfigurable metasurfaces in the optical and NIR regimes with low energy
consumption, low footprint and high reliability. Continuously tunable resonant
structures suffer from inherent drawbacks such as low phase range,
amplitude-phase correlation or extreme sensitivity that makes precise control
at the individual element level very challenging. In order to bypass these
issues, we use 1-bit (binary) control for beam steering for an innovative
nano-resonator antenna and explore the theoretical capabilities of such phased
arrays. A thermally realistic structure based on vanadium dioxide sandwiched in
a metal-insulator-metal structure is proposed and optimized using inverse
design to enhance its performance at 1550 nm. Continuous beam steering over
90{\deg} range is successfully achieved using binary control, with excellent
agreement with predictions based on the theoretical first principles
description of phased arrays. Furthermore a broadband response from 1500 nm to
1700 nm is achieved. The robustness of the design manufacturing imperfections
is also demonstrated. This simplified approach can be implemented to optimize
tunable nanophotonic phased array metasurfaces based on other materials or
phased shifting mechanisms for various functionalities.
