UC San Diego

This thesis advances ultra-wideband, high-linearity phased-array beamformers and transceiver systems for 5G and 6G applications, addressing critical challenges in next-generation wireless communication. Chapter 1 summarize the background and the state-of-the-art of the phased array system and it application in 5G and 6G system. Chapter 2 introduces a 2.5-25 GHz 8-channel beamformer leveraging a novel quad-pole I/Q network, which achieves $<$±5° phase error and low conversion loss over a 10:1 bandwidth. The beamformer exhibits an RMS phase error of 2.7° and an IP1dB of -28 to -25 dBm, validated by a 16-element array, showcasing its suitability for ultra-wideband 6G FR3 systems. Chapter 3 presents an 8-channel phased-array receiver operating from 3 to 28 GHz, designed for 6G FR3 base stations. Fabricated in a 90 nm SiGe BiCMOS process, the receiver integrates eight channels with dual 4:1 combiner networks, enabling dual-polarized, dual-beam operation. It achieves 25-34 dB gain, 2-4.5 dB noise figure, and -35 to -28 dBm input 1 dB compression point (IP1dB), with ±50° beam scanning demonstrated using a 16-element array and 64-QAM signals. Chapter 4 proposes a 4-40 GHz reconfigurable IQ/image-reject receiver for phased-array down-conversion modules. The design integrates a quad-pole quadrature all-pass filter (QAF) network with $<$±5° phase error and a phase detection feedback loop to compensate for PVT variations. It supports a 3 GHz baseband bandwidth and achieves $>$20 dB image rejection, with 8-15 dB conversion gain and -19 to -16 dBm IP1dB. Together, these contributions demonstrate robust performance across wide bandwidths, high linearity, and advanced beamforming, paving the way for future multiband 5G/6G systems. Chapter 5 focuses on wideband single and dual-polarized phased arrays for 5G MIMO, operating from 22 to 46 GHz. The antenna design incorporates a dipole-fed split-ring resonator (SRR), enabling continuous operation across the N257-N261 bands. An 8×8 single-polarized array achieves 42-48 dBm EIRP and $>$55° beam scanning, while a 4×2 dual-polarized array supports 2×2 MIMO with high isolation and 23-32 dBm EIRP per polarization. System-level measurements using 5G-NR and 64-QAM modulation at 400 Mbaud confirm its readiness for multi-standard 5G applications. Chapter 6 concludes the thesis.