As early adopters of beamforming technology in the 1960s, aerospace and defense organizations have a lot of experience using the initial large-scale active electronically scanned arrays (AESAs) for military radar tracking applications. But these arrays aren’t as convenient for some applications today as the operational frequencies of the targets of interest for many military applications are increasing. This means the wavelengths of the signals that need to be monitored are getting shorter and these radar applications need denser arrays since antenna spacing needs to be set at one half the wavelength. For example, at 25GHz, the wavelength in free space is approximately 12mm (0.47”), leading to half-wave spacing for antennas of 6mm (0.24”). Also, as arrays become denser, the new challenge for RF system designers is avoiding interference in these tighter spaces, especially when transmitting signals.
Therefore, there are a number of benefits that fully digital beamforming can potentially bring to many emerging military applications – especially those in the electronic warfare space. First, at a high level, fully digital beamforming has a dedicated analog-to-digital converter (ADC) for every antenna element. This allows the array to simultaneously acquire and transmit multiple beams, and beams can be split in various directions at the same time without having interference issues and all while improving dynamic range.