A 16-element 4-beam 1GHz-IF 100MHz-bandwidth Interleaved Bit-Stream digital beamformer in 40nm CMOS

Abstract

This paper introduces a 16 element, 1GHz IF input, digital beamformer (DBF) that generates 4 independent simultaneous beams, with 100MHz bandwidth. Although DBF has several advantages over analog beamforming, including higher accuracy and multiple beam generation, application of on-chip DBF has been limited due to high power consumption and large die area. The proposed architecture addresses these issues by combining efficient Continuous-Time Band-Pass Delta Sigma Modulators (CTBPDSMs) with Interleaved Bit-Stream Processing (IL-BSP). IL-BSP saves 80% power and 80% area compared to a conventional DSP approach. The overall 16 element array has a measured 58.5dB SNDR and a 59.6dB SNR over a 100MHz bandwidth (11.2dB array gain). Thanks to the IL-BSP approach, the measured beam patterns are near ideal.