Broadband Scattering-Tunable Phased Array With Stable ±45° Beam Steering

In this letter, a broadband scattering-tunable phased array with stable ±45° beam steering is presented. The array consists of 64 antenna elements and their bias circuits. The antenna element controlled by p-i-n diodes possesses two switchable scattering states, which exhibit a reflection phase difference of 180° ± 37° and with nearly identical radiation performances. The asymmetric-arm antenna element excites additional resonances, significantly extending the scattering-tunable bandwidth for x-polarized incident waves. The element is excited to radiate the y-polarized wave. Polarization decoupling allows independent control of y-polarized radiation and x-polarized reflection phase. The two switchable scattering states of the antenna element exhibit the required phase difference across 6.6-13.9 GHz (71.2%), while maintaining radiation stability over 8-12 GHz band. Moreover, the scattering characteristics of the designed array are optimized under the normal incident wave. Measured results show good agreement with simulated results, validating the array design.