Wideband analog and digital beamforming

High quality beamforming is necessary for the integrity of phased arrays and accuracy of monopulse direction finding systems. Traditionally, beamformers are realized as hybrid or monolithically integrated analog sub-systems. Their wideband operation is plagued by higher loss, amplitude and phase misbalances, weight, complex integration, etc. All these factors contribute to the errors in beam-pointing and geo-location, as well as antenna pattern contamination. This paper compares the performance of analog and digital beamformers realized for wideband operation through HF/VHF range. Recent advances in digital integrated circuits have contributed to not only improved performance of analog to digital (ADC) and digital to analog (DAC) converters and field-programmable gate arrays (FPGAs) but also to their reduced cost. Thus, we are now able to realize complete modeforming functionality in a digital domain and thus enhance the performance of beamformers. Modelling, performance, and realization of analog and digital beamformers for the mode 1 operation of a 4-arm spiral are discussed and relevant conclusions drawn.