A Low-Cost and Low-Profile Electronically Programmable Bit Array Antenna for Two-Dimensional Wide-Angle Beam Steering

An electronically programmable bit array antenna (PBAA) is designed with a low profile ( $0.09\lambda _{0}$ at 11 GHz) and 2-D wide-angle beam steering. The planar PBAA is composed of 8 $\times8$ elements, and each of them can be individually addressed through the meticulously designed dc bias. By controlling two PIN diodes and four varactor diodes embedded, the PBAA element provides a maximum phase shift of 337.5° and 16 (4 bit) phase coding states with a 22.5° regular interval. The design is verified through simulations and measurements. The experimental results of the fabricated sample exhibit a broadside gain of 16 dBi, corresponding to the radiation efficiency of 33.1%, and 3 dB gain bandwidth of 11.8%. The sidelobe and cross-polarization levels of the broadside beam are below −19.6 and −30 dB, respectively. Moreover, the main beam is capable of scanning in the range of ±60° $\times$ ±40°, and the gain fluctuations in E- and H-planes are less than 3.6 and 3 dB, respectively. The design provides flexible 2-D beam-scanning capability while being low cost, low profile, low complexity, and low power consumption, which will benefit various applications with sensing and wireless communication through electromagnetic (EM) waves.