Hybrid Beamforming Architecture and Wide Bandwidth True-Time Delay for Future High Speed Communications 5G and Beyond 5G Beamforming System

Multi Antenna systems such as beamforming and MIMO are anticipated to play a key role in 5G and beyond 5G communications. The Phased Array Antennas(PAAs) with phase shifter is the dominant method to achieve beamforming up to now. However the operation bandwidth of PAAs is limited to narrow(~200MHz) due to beam-squint problem. In beyond 5G, hundreds of Gbps data rate are required so the traditional PAAs based beamforming will face technical difficulties in the future. In this paper we proposed new beamforming architecture and an analog True-time delay(TTD) circuit which covers 4.8 GHz bandwidth. The architecture is a combination of phase shifters and TTDs. The analog TTD is composed of all-pass filter based cascade delay cells. The experimentally demonstrated TTD can support 590 psec total-delays with 40 psec resolution which covers more than 1024 number of array in mm-wave 5G system. The measured delay variance is within 4.09 % over the whole operating bandwidth. As a result the proposed scheme is a good candidate for large array and wide width beamforming system.

I. Introduction

Despite of wide spread deployment of 4G communications, the demand for higher data rates and lower latency is consistently increasing. There are abundance of mm-wave frequency bands that meet current demands and there are many research efforts into using these bands as the name of 5G communications [1]–[2].