A polyphase architecture for broadband bandpass beamforming for arrays of arbitrarily placed sensors

Abstract

A new polyphase architecture is proposed for the beam-forming of far-field temporally-broadband-bandpass signals received by an array of arbitrarily placed sensors. The sensor signals are demodulated using an array of synchronous mixers prior to temporal sampling using an array of time-interleaved analog-to-digital converters (TI-ADCs). The sampled data sequences are processed with a novel polyphase FIR filter structure to form the beamformer output. The filter coefficients are determined using a combination of design methods that involve modal subspace decomposition (MSD), bandpass filtering and polyphase noble identities. The proposed method achieves significantly lower sampling rates and operational clock rates compared to the direct-form implementation.