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Most research works on reconfigurable intelligent surfaces (RIS) rely on idealized models of the reflection coefficients, i.e., uniform reflection amplitude for any phase and sufficient phase shifting capability. In practice however, such…

Signal Processing · Electrical Eng. & Systems 2024-04-17 Lin Cao , Haifan Yin , Li Tan , Xilong Pei

The optimal spectral efficiency and number of independent channels for MIMO antennas in isotropic multipath channels are investigated when bandwidth requirements are placed on the antenna. By posing the problem as a convex optimization…

Signal Processing · Electrical Eng. & Systems 2021-09-07 Casimir Ehrenborg , Mats Gustafsson , Miloslav Capek

A general algorithm for calculating the reflection and refraction of nonuniform plane waves from an arbitrarily oriented and charged planar interface between two lossy isotropic media is proposed based on the decomposition of the complex…

Optics · Physics 2026-02-24 Zhili Lin

A method is proposed which allows a complete determination of the complex reflection coefficient for any free unknown real potential (i.e., in the case where there is no effective absorption). In this method the unknown layer mounted on top…

Materials Science · Physics 2015-06-24 S. F. Masoudi , A. Pazirandeh

This paper continues the preceding paper on the problem of quantum dynamics on the lattice. Firstly we consider the multiple reflections of the wave function (Loschmidt echo). The phenomenon of wave function concentration on the impurity…

Mesoscale and Nanoscale Physics · Physics 2013-02-13 V. N. Likhachev , T. Yu. Astakhova , G. A. Vinogradov

Multiport network theory has been proved to be a suitable abstraction model for analyzing and optimizing reconfigurable intelligent surfaces (RISs) in an electromagnetically consistent manner, especially for studying the impact of the…

Information Theory · Computer Science 2024-07-30 Andrea Abrardo , Alberto Toccafondi , Marco Di Renzo

This paper investigates energy efficiency maximization for movable antenna (MA)-aided multi-user uplink communication systems by considering the time delay and energy consumption incurred by practical antenna movement. We first examine the…

Information Theory · Computer Science 2025-09-03 Jingze Ding , Zijian Zhou , Lipeng Zhu , Yuping Zhao , Bingli Jiao , Rui Zhang

In millimeter wave (mmWave) systems, the advanced lens antenna array can effectively reduce the radio frequency chains cost. However, the mmWave signal is still vulnerable to blocking obstacles and suffers from severe path loss. To address…

Signal Processing · Electrical Eng. & Systems 2020-07-03 Yazheng Wang , Hancheng Lu , Dan Zhao , Huan Sun

Intelligent reflecting surface (IRS) is a promising technology to boost the efficiency of wireless energy transfer (WET) systems. However, for a multiuser WET system, simultaneous multi-beam energy transmission is generally required to…

Information Theory · Computer Science 2022-05-19 Chi Qiu , Qingqing Wu , Meng Hua , Xinrong guan , Yuan Wu

A design methodology for planar loaded antenna arrays is proposed to synthesize a perfect anomalous reflection into an arbitrary direction by optimizing the scattering characteristics of passively loaded array antennas. It is based on…

Applied Physics · Physics 2024-09-26 Sravan K. R. Vuyyuru , Risto Valkonen , Sergei A. Tretyakov , Do-Hoon Kwon

This paper evaluates the performance of multi-user massive multiple-input multiple-output (MIMO) systems in which the base station is equipped with a dynamic metasurface antenna (DMA). Due to the physical implementation of DMAs,…

Signal Processing · Electrical Eng. & Systems 2022-06-28 Pablo Ramírez-Espinosa , Robin Jess Williams , Jide Yuan , Elisabeth de Carvalho

Existing optimization methods are used to calculate the upper-bounds on radiation efficiency with and without the constraint on self-resonance. These bounds are used for the design and assessment of small electric-dipole-type antennas. We…

Classical Physics · Physics 2019-04-05 L. Jelinek , K. Schab , M. Capek

The present paper studies the asymptotic performance of multi-hop amplify-and-forward relay multiple-antenna communication channels. Each multi-antenna terminal in the network amplifies the received signal, sent by a source, and retransmits…

Information Theory · Computer Science 2016-06-24 Maksym A. Girnyk , Mikko Vehkaperä , Lars K. Rasmussen

Densifying networks and deploying more antennas at each access point are two principal ways to boost the capacity of wireless networks. However, the complicated distributions of the signal power and the accumulated interference power,…

Information Theory · Computer Science 2018-09-25 Xianghao Yu , Chang Li , Jun Zhang , Martin Haenggi , Khaled B. Letaief

In this paper, we propose intelligent reflecting surfaces (IRS) assisted secure wireless communications with multi-input and multi-output antennas (IRS-MIMOME). The considered scenario is an access point (AP) equipped with multiple antennas…

Information Theory · Computer Science 2020-01-27 Weiheng Jiang , Yu Zhang , Jinsong Wu , Wenjiang Feng , Yi Jin

Active sensing refers to the process of choosing or tuning a set of sensors in order to track an underlying system in an efficient and accurate way. In a wireless environment, among the several kinds of features extracted by traditional…

Information Theory · Computer Science 2016-05-30 Alessandro Biason , Urbashi Mitra , Michele Zorzi

This paper studies the performance of single-input multiple-output (SIMO) systems under receive antenna selection (RAS) and BPSK/QPSK modulations. At the receiver, a subset of branches are selected and combined using maximal-ratio combining…

Signal Processing · Electrical Eng. & Systems 2019-07-16 Chongjun Ouyang , Zeliang Ou , Pei Yang , Lu Zhang , Hongwen Yang , Xin Zhang

Undesired wave reflections, which occur at domain boundaries in flow simulations with free-surface waves, can be minimized by applying source terms in the vicinity of the boundary to damp the waves. Examples of such approaches are absorbing…

Fluid Dynamics · Physics 2017-11-13 Robinson Perić , Moustafa Abdel-Maksoud

A method for modeling a reflector antenna system with a wideband phased array feed is presented and used to study the effects of the number of active antenna elements and associated receiving channels on the sensitivity of the system.…

Instrumentation and Methods for Astrophysics · Physics 2011-10-21 Oleg Iupikov

This paper explores the idea of using redirective reconfigurable intelligent surfaces (RedRIS) to overcome many of the challenges associated with the conventional reflective RIS. We develop a framework for jointly optimizing the switching…

Information Theory · Computer Science 2024-06-04 Bamelak Tadele , Faouzi Bellili , Amine Mezghani , Md Jawwad Chowdhury , Haseeb Ur Rehman