References & Further Reading

References

T. J. Cui, M. Q. Qi, X. Wan, J. Zhao, and Q. Cheng, Coding metamaterials, digital metamaterials and programmable metamaterials, 2014
The founding paper of the digital-coding-metasurface concept. Introduces the 1-bit/2-bit coding representation of a programmable surface and sets the terminology.
Q. Wu and R. Zhang, Beamforming Optimization for Wireless Network Aided by Intelligent Reflecting Surface With Discrete Phase Shifts, 2020
The definitive reference on discrete-phase RIS. Derives the $\text{sinc}^2(\pi/2^B)$ loss formula and proves near-optimality of nearest-level projection for coherent combining.
S. Abeywickrama, R. Zhang, Q. Wu, and C. Yuen, Intelligent Reflecting Surface: Practical Phase Shift Model and Beamforming Optimization, 2020
Introduces the amplitude-phase coupling (APC) model based on fitting measured varactor-diode data. Quantifies the naive-vs-APC-aware optimization gap.
R. J. Williams, P. Ramírez-Espinosa, E. de Carvalho, and T. L. Marzetta, Multiport Communication Theory for Reconfigurable Intelligent Surfaces, 2021
Treats the RIS as a multiport network with explicit mutual-impedance matrix. The starting point for the 'beyond-diagonal' RIS optimization of Chapter 10.
W. Tang et al., Wireless Communications With Reconfigurable Intelligent Surface: Path Loss Modeling and Experimental Measurements, 2021
First experimental validation of the RIS cascaded-channel model with a 1-bit prototype. Measures and reports the 1-bit SNR loss and the $N^2$ coherent combining gain.
M. Di Renzo et al., Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and the Road Ahead, 2020
Section III (hardware) is the most complete introduction to unit-cell design options. Section IV (modeling) treats the diagonal-model validity question in detail.
D. M. Pozar, Microwave Engineering, Wiley, 4th ed., 2012
Chapters 2 and 3 on transmission lines, impedance matching, and S-parameters are the required background for the hardware models of this chapter.
R. F. Harrington, Matrix methods for field problems, 1967
The foundational paper on the method of moments (MoM) for computing mutual-impedance matrices. Still the practical starting point for computing $\mathbf{Z}$ in a real array.
Q. Wu, S. Zhang, B. Zheng, C. You, and R. Zhang, Intelligent Reflecting Surface-Aided Wireless Communications: A Tutorial, 2021
A tutorial survey of RIS algorithms and architectures. Good for placing this chapter's hardware focus in the context of the broader RIS design space.
V. Arun and H. Balakrishnan, RFocus: Beamforming using thousands of passive antennas, 2020
The RFocus demonstrator at MIT — 3,200 passive 1-bit elements at 2.4 GHz. The benchmark 'empirical result' that all theoretical papers compare against.
X. Yang et al., A programmable metasurface with dynamic polarization, scattering and focusing control, 2016
An earlier programmable metasurface prototype that predates the RIS-for-communications paradigm. Useful for understanding the physics-first perspective.