Beamforming techniques for massive MIMO systems in 5G: overview, classification, and trends for future research

E Ali, M Ismail, R Nordin, NF Abdulah - Frontiers of Information …, 2017 - Springer
Massive multiple-input multiple-output (MIMO) systems combined with beamforming
antenna array technologies are expected to play a key role in next-generation wireless …

Circuit type multiple beamforming networks for antenna arrays in 5G and 6G terrestrial and non-terrestrial networks

YJ Guo, M Ansari, NJG Fonseca - IEEE Journal of Microwaves, 2021 - ieeexplore.ieee.org
To support the ever-increasing demand on connectivity and datarates, multiple beam
antennas are identified as a critical technology for the fifth generation (5G), the sixth …

Butler matrix based beamforming networks for phased array antenna systems: A comprehensive review and future directions for 5G applications

AK Vallappil, MKA Rahim, BA Khawaja… - IEEE …, 2020 - ieeexplore.ieee.org
Due to the rapid development of wireless communication technologies, the number of
wireless users are radically increasing. Currently,~ 23 billion wireless devices are …

A Novel 2-D Nolen Matrix for 2-D Beamforming Applications

H Ren, H Zhang, Y Jin, Y Gu… - IEEE Transactions on …, 2019 - ieeexplore.ieee.org
In this paper, a 2-D beamforming phased array using a novel 2-D Nolen matrix network is
presented. The Nolen matrix is a novel antenna feeding network composed of only couplers …

Asymmetrical Butler Matrix and its Application for Single Layer Butler Matrix

A Tajik, AS Alavijeh… - IEEE transactions on …, 2019 - ieeexplore.ieee.org
The design procedure and measured results of a novel Butler matrix are presented in this
paper. This asymmetrical structure provides fairly flexible phase outputs; therefore, the array …

Wideband hybrid couplers with unequal power division/arbitrary output phases and applications to miniaturized Nolen matrices

H Zhu, T Zhang, YJ Guo - IEEE Transactions on Microwave …, 2022 - ieeexplore.ieee.org
In this article, a new design approach for developing hybrid couplers with arbitrary power
division and the phase difference is presented. The design is based on a transformer-based …

Orthogonal versus zero-forced beamforming in multibeam antenna systems: Review and challenges for future wireless networks

Y Aslan, A Roederer, NJG Fonseca… - IEEE Journal of …, 2021 - ieeexplore.ieee.org
Orthogonality in multibeam antennas is revisited. The difference between orthogonal
beamforming and zero-forced beamforming is highlighted. The intriguing relation between …

Phase shifter-relaxed and control-relaxed continuous steering multiple beamforming 4× 4 Butler matrix phased array

H Ren, P Li, Y Gu, B Arigong - IEEE Transactions on Circuits …, 2020 - ieeexplore.ieee.org
A novel continuous tunable phase progression beamforming feeding network is proposed
using 4× 4 Butler matrix and tunable phase shifters. To tune the progressive phase …

Taxonomy and performance evaluation of hybrid beamforming for 5G and beyond systems

M Rihan, TA Soliman, C Xu, L Huang… - IEEE Access, 2020 - ieeexplore.ieee.org
Increasing demand for higher data-rate wireless connectivity with lower latency is fueling the
explorations of millimeter-wave (mmWave) spectrum and massive MIMO communications …

2-D Butler matrix and phase-shifter group

K Ding, AA Kishk - IEEE transactions on microwave theory and …, 2018 - ieeexplore.ieee.org
The principles and design methods of two novel devices, 2-D Butler matrix (2-D-BM) and
phase-shifter group, are presented. The 2-D-BM has 2M+ N× 2M+ N configurations that can …