Electronically scanned arrays (ESAs) utilize phase shifters (PSs), true time delays (TTDs), or a mix of both to pointthe summed beam toward the desired direction within an array’s steering anglelimits.Adjustableattenuatorsusedfortaperingalso canbeconsideredasbeamforming elements.
This article discusses where and how a tiered approachbetween TTDs and PSs in the same ESA can be helpful to mitigate some phased-array design challenges.