Next Generation mm-Wave Technology: Beamforming with Joint Phase and Time Array

Analog beamforming has been widely used to overcome excessive path loss in mm-wave 5G. The single-beam system limits the beam-pairing capability and allocated transmission time when multiple users are connected to the base station. These constraints limit the coverage and capacity of mm-wave systems. Multi-beam beamforming could potentially overcome these challenges. However, the conventional schemes, such as hybrid or fully-digital, require multiple power-hungry digital chains. Joint Phase-Time Array (JPTA) allows frequency-dependent multiple beams to be supported with only one digital chain with time delays of several nanoseconds. Recent progress of delay lines using low-cost CMOS technology has made JPTA practically feasible. We will introduce JPTA system design, benefits and challenges. We will also demonstrate a 28GHz prototype system supporting 4 UEs simultaneously at different directions each with 100MHz 5G NR signals.