A Wideband Beamformer using 3.25 GS/sec Discrete-time Analog FIR Filter ICs

Discrete-time analog finite-impulse-response (AFIR) filter integrated circuits (ICs) implemented with split-capacitive digital-to-analog (CDAC) coefficient multiplier are utilized to implement a wideband beamformer. AFIR filter modules are built on printed-circuit boards (PCBs) so that multiple inputs are injected to each module and their outputs are summed through RF combiner. A set of 4 modules was considered to form a FIR-based beamformer, for a 4 antenna element array. In lieu of comprehensive study, a simplified method for coefficient calculation is developed. Overall measurement results follow the desired beam steering and frequency selection.