A 14–50-GHz Phase Shifter With All-Pass Networks for 5G Mobile Applications

In this article, an ultra-broadband phase shifter (PS) with a 14-50-GHz bandwidth (defined by a phase error below 1/2 LSB) is presented to address the multiband requirements of 5G millimeter-wave (mm-wave) systems. The PS construction is based on all-pass networks (APNs), which have shown broad bandwidth capabilities in a lower frequency range. Aiming toward 5G mobile applications, the proposed 2-bit, 45° phase resolution PS was implemented in 0.25-μm BiCMOS, manufactured, and measured, achieving an insertion loss of 7.4 ± 0.26 dB at 28 GHz and 10 ± 0.22 dB at 39 GHz, with an rms gain and phase error c0.27 dB and c4° from 24 to 30 GHz, respectively, and c0.33 dB and c6° from 37 to 43.5 GHz, demonstrating its capabilities to cover the 5G mm-wave spectrum.