A Nonfully Filled Sparse Phased Array for Wide-Angle High-Gain Scanning Based on 1-bit Encoded Subarrays

A novel non-fully filled 1-bit amplitude-encoded sparse phased array (ESPA) is proposed to enhance both boresight efficiency and wide-angle scanning performance. An ideal subarray gain degradation model was established, and power divider non-idealities were incorporated to evaluate the performance of different excitation schemes. The [1,1,0,0] “two-on–two-off” configuration was identified as the optimal structure, offering a simplified feed network while compensating for boresight gain loss through parasitic element coupling. Six excitation states were defined as “encoding blocks” and used to construct array topologies. An Encoding Autocorrelation Function (EAF) was introduced to quantify spatial regularity and suppress grating lobes. Sparse layouts were optimized using a discrete simulated annealing algorithm. Full-wave simulations of an 8×8 array with parasitic patches placed at inactive positions showed that the proposed 1-bit ESPA improves boresight gain by approximately 1.0 dB compared to existing wide-angle sparse subarray schemes, with more than 1.5 dB enhancement at θ = 45°, while maintaining good polarization purity and wide scan angles. These results validate the proposed approach, demonstrating its advantages in both efficiency and wide-angle performance.