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DESCRIPTION:Abstract\n\nMassive multiple-input multiple-output (mMIMO) tech
 nology has emerged as a key enabler for future wireless systems\, providin
 g substantial gains in capacity and coverage through large-scale antenna a
 rrays. With strategically designed beamforming algorithms\, these arrays c
 an precisely direct radiation toward intended users while effectively supp
 ressing interference\, thereby boosting spectral efficiency and signal qua
 lity. Metamaterial-based structures with tunable electromagnetic (EM) prop
 erties present promising avenues for further improving large-scale array p
 erformance by facilitating miniaturized\, high-isolation antenna elements 
 and enabling novel interference mitigation strategies. Moreover\, hybrid b
 eamforming (HBF) schemes that integrate radio-frequency (RF) beamformers w
 ith digital baseband precoders/combiners using fewer RF chains effectively
  reduce both hardware and computational complexity while maintaining perfo
 rmance through the joint design of the two stages. This thesis investigate
 s and develops metamaterial-based large-scale antenna arrays alongside bea
 mforming optimization techniques for both half-duplex (HD) multi-user mMIM
 O (MU-mMIMO) and full-duplex (FD) mMIMO systems. Extensive full-wave simul
 ations and experimental measurements evaluate the performance of various p
 rototype arrays\, considering factors such as array aperture size\, sub-ar
 ray placement\, and surrounding environments.\n	\n	In the first part\, vario
 us nulling control beamforming (NCB) optimization algorithms are proposed\
 , leveraging both deterministic and nature-inspired approaches while accou
 nting for realistic EM characteristics such as heterogeneous element radia
 tion patterns. These algorithms target far-field\, angular-separation-base
 d interference scenarios and near-field\, location-differential cases invo
 lving spherical wavefronts in extra-large arrays. Full-wave simulations il
 lustrate how beam radiation patterns transition from near-field to far-fie
 ld propagation with increasing distance. Through simulations and experimen
 tal measurements conducted in an anechoic chamber with the proposed array 
 prototypes\, the NCB techniques effectively create deep\, accurately align
 ed nulls that reduce residual multi-user interference (MUI) to noise level
 s while maintaining the desired signal gain.\n	\n	In the second part\, the t
 hesis explores FD mMIMO communications\, where concurrent transmission and
  reception further enhance spectral efficiency. Metamaterial-based large-s
 cale arrays offer additional degrees of freedom for suppressing self-inter
 ference (SI)\, a critical challenge in FD operations. A multi-stage transm
 it-receive isolation framework is proposed\, encompassing: (1) antenna iso
 lation techniques\, (2) joint uplink/downlink beamforming optimization\, a
 nd (3) integration of metamaterial absorber structures. Experimental resul
 ts demonstrate the effectiveness of these methods in collectively mitigati
 ng SI\, preventing receiver front-end saturation and nonlinear distortion.
  Through experimental measurements\, the study examines the correlation be
 tween beam radiation patterns and beam-level mutual coupling\, as well as 
 the effectiveness of various isolation techniques\, offering valuable and 
 practical insights into the development of beam-level isolation strategies
 . By combining these isolation measures with self-interference cancellatio
 n techniques\, residual SI is reduced to the noise floor\, thereby ensurin
 g reliable FD mMIMO communication performance.\n
DTSTART:20250424T150000Z
DTEND:20250424T170000Z
LOCATION:Room 603\, McConnell Engineering Building\, CA\, QC\, Montreal\, H
 3A 0E9\, 3480 rue University
SUMMARY:PhD defence of Yuanzhe Gong – Metamaterial-Based Large-Scale Array 
 for Half-Duplex/Full-Duplex mMIMO
URL:/ece/channels/event/phd-defence-yuanzhe-gong-metam
 aterial-based-large-scale-array-half-duplexfull-duplex-mmimo-365035
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