This paper analyzes the ergodic rate of a wideband reconfigurable intelligent surface (RIS)-assisted terahertz link under beam squint and finite-resolution phase control. Independent Rayleigh fading on the two RIS-assisted hops produces double-Rayleigh cascaded amplitudes. Exact second- and fourth-order channel moments are derived by incorporating the frequency-dependent array response and phase-quantization errors. Moment matching then provides a Gamma approximation for the received power on each subcarrier and a tractable closed-form approximation for the wideband ergodic rate. A first-null bandwidth approximation characterizes the aperture--bandwidth limitation of frequency-flat RIS control. Monte Carlo simulations validate the analytical framework.
Multi-frequency operation in beyond-5G and 6G systems renders the beam directions of large-aperture arrays inherently frequency-dependent, giving rise to beam misalignment effects that are particularly critical for reconfigurable intelligent surfaces (RISs). When an RIS phase profile is configured at one frequency but...
Mohammad Amin Saeidi, Hina Tabassum· IEEE Transactions on Wireles...· 0 citations
Wideband terahertz (THz) communication systems assisted by active reconfigurable intelligent surfaces (RIS) are susceptible to frequency dependent beam squint, which degrades the array gain at band edge subcarriers and reduces the achievable rate. In active RIS architectures, mitigating this effect requires the inserti...
Faran Awais Butt, A. A. Nasir, A. Muqaibel· IEEE Open Journal of the Com...· 0 citations
Extremely large-scale array (XL-array) is envisioned as a key technology for future terahertz (THz) communication networks. However, the near-field beam split effect severely degrades beam training performance in wideband THz XL-array systems. In this letter, we reveal that the near-field array gain is considerably mor...
Ke Huang, Jian-He Du, Jing-Yi Guan et al.· IEEE Wireless Communications...· 0 citations
Dynamic metasurface antennas (DMAs) have emerged as a promising solution for reducing cost and power consumption in next-generation wireless systems employing large antenna arrays. Existing studies on DMA-based architectures typically adopt a frequency-flat approximation to model the frequency response of individual el...
Abdolrasoul Sakhaei Gharagezlou, M. Monemi, Mehdi Rasti et al.· IEEE Transactions on Communi...· 1 citation
The combination of extremely large-scale antenna arrays and ultra-wideband transmission enables future wireless communications systems to deliver the requested increase in data rates. Nevertheless, the employment of large-scale phased arrays with high relative bandwidths is limited by the beam-squint phenomenon. Two pr...
Robert Walstab, Torge Mewes, Ahmad Nimr et al.· IEEE International Symposium...· 0 citations
Reflectarray antennas (RAs) combine the high gain and low-loss space feed of reflectors with the per-element phase control of phased arrays, but their resonant, path-length-dependent operation makes bandwidth their principal limitation. The paper presents a comprehensive review of techniques developed to widen the band...
R. S. Malfajani, A. Kishk· IEEE Access· 0 citations
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