Cross-Mixing Hybrid Beamformer for Wideband Apertures

Abstract

Existing beamforming arrays suffer from the size and cost of the RF front-end and digital back-end components. In this paper, a novel hybrid beamforming configuration for wideband receivers is introduced. The design replaces phase shifters and local oscillators (LO) with cross mixing antenna elements to maximize diversity gain. In this paper, an analytical model of the cross mixing beamformer (CMB) is first presented. Simulations are carried out showing that a maximum diversity gain can be achieved with the CMB approach. Two prototypes were implemented using 2 × 1 and 4 × 2 element arrays and tested at 2.31 GHz. Measured results show that CMB achieves coherent signal combining and can preserve the phase delay information needed for hybrid beamforming setups.INDEX TERMS Antenna arrays, antenna subarrays, beamforming, frontend circuitry, front end circuits and systems, RF front ends, self-mixing, self-mixing array, self-mixing subarray, wideband apertures, wide beamwidth.