Phase Shifter Digitalization Effect On The Scanning Performance Of Phased Array Antenna With Integrated Subarrays

The use of a digital phase shifter can enhance the scanning ability of a phased array antenna with an integrated subarray for wide-angular scanning applications. In the existing literature, scanning still relies on analog phase values, indicating the absence of phase quantization. However, phase quantization can adversely impact scanning performance, leading to issues such as beam squinting and high sidelobe levels. Therefore, it is crucial to investigate the effects of digitalizing the phase shifter on wide-angular scanning performance. This study analyzes several types of digital phase shifters, namely 2-bit, 4-bit, 6-bit, 8-bit, and 10-bit, to assess their impact. In this research scenario, the phased array antenna is scanned at different angles in the azimuth direction: 5°, 35°, and 60°. The analysis reveals that phase excitations produced by digital phase shifters below 8 bits give a very high deviation value. This phase deviation result in poor phased array antenna performance, characterized by sidelobe levels exceeding −10 dB and beam squinting larger than 50° when the antenna is scanned large scan angle of 60°. According to the obtained results, the use of digital phase shifter below 8 bits is not recommended in the phased array antenna with integrated subarrays configuration for wide-angular scanning application.