How does a digital array radar differ from an analog beamforming array in military applications?

A digital array radar digitizes the received signal at every antenna element (or small subarray), providing each element with its own analog-to-digital converter (ADC) and digital receiver channel, whereas an analog beamforming array combines element signals in the analog domain using phase shifters and power combiners before digitization. The key advantage of digital arrays is the ability to form multiple simultaneous receive beams from a single set of element data, enabling the radar to look in many directions at once without time-sharing the beam. Digital arrays also support space-time adaptive processing (STAP) that jointly optimizes spatial and temporal filtering for superior clutter and jammer rejection, and they allow aperture synthesis techniques that can form beams with resolution finer than the physical aperture. The trade-off is that digital arrays require one ADC per element (or per small subarray), dramatically increasing the data throughput (terabits per second for large arrays), power consumption, and processing requirements compared to analog arrays. Current military AESA radars (like AN/APG-81, AN/APG-83) use analog beamforming on transmit and receive, but next-generation systems are moving toward digital receive arrays with analog transmit (hybrid digital-analog architecture) as ADC technology and processing power improve.