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Scattering of electromagnetic (EM) waves by many small particles (bodies) embedded in a homogeneous medium is studied. Physical properties of the particles are described by their boundary impedances. The limiting equation is obtained for…

Mathematical Physics · Physics 2011-01-18 A. G. Ramm

Motivated by the ever-growing demand for \emph{green} wireless communications and the advantages of \emph{cell-free} (CF) massive multiple-input multiple-output (MIMO) systems, we focus on the design of their downlink for optimal…

Information Theory · Computer Science 2021-02-09 Anastasios Papazafeiropoulos , Hien Q. Ngo , Pandelis Kourtessis , Symeon Chatzinotas , John M. Senior

This paper studies the uplink spectral efficiency (SE) achieved by two single-antenna user equipments (UEs) communicating with a Large Intelligent Surface (LIS), defined as a planar array consisting of $N$ antennas that each has area $A$.…

Signal Processing · Electrical Eng. & Systems 2020-11-30 Andrea de Jesus Torres , Luca Sanguinetti , Emil Björnson

An effective-medium theory (EMT) is developed to predict the effective permittivity \epsilon_eff of dense random dispersions of high optical-conductivity metals such as Ag, Au and Cu. Dependence of \epsilon_eff on the volume fraction \phi,…

Materials Science · Physics 2015-06-04 Satvik N. Wani , Ashok S. Sangani , Radhakrishna Sureshkumar

Enormous fluid antenna systems (E-FAS) have recently emerged as a surface-wave (SW)-enabled architecture that can induce controllable large-scale channel gains through guided electromagnetic routing. This paper develops a secrecy analysis…

Information Theory · Computer Science 2026-03-30 Farshad Rostami Ghadi , Kai-Kit Wong , Masoud Kaveh , Mohammad Javad Ahmadi , Kin-Fai Tong , Hyundong Shin

Fluid antenna systems (FAS) offer a promising paradigm for enhancing wireless communication by exploiting spatial diversity, yet a rigorous analytical framework for their error probability has been notably absent. To this end, this paper…

Information Theory · Computer Science 2025-11-06 Xusheng Zhu , Farshad Rostami Ghadi , Tuo Wu , Kaitao Meng , Chao Wang , Gui Zhou

A well-known lower bound widely used in the massive MIMO literature hinges on channel hardening, i.e., the phenomenon for which, thanks to the large number of antennas, the effective channel coefficients resulting from beamforming tend to…

Information Theory · Computer Science 2017-10-27 Giuseppe Caire

High energy electron beams can now be routinely focused to 1-2 {\AA} and offer the ability to obtain vibrational information from materials using monochromated electron energy-loss spectroscopy (EELS) in a scanning transmission electron…

Materials Science · Physics 2021-07-13 Kartik Venkatraman , Peter A. Crozier

A unified framework for the characterization of continuous electromagnetic (EM) manifolds for arbitrary multipleinput multiple-output (MIMO) system geometries is presented. The EM manifold refers to the set of all physically realizable…

Signal Processing · Electrical Eng. & Systems 2026-05-11 Kuranage Roche Rayan Ranasinghe , Miguel Rodrigo Castellanos , Giuseppe Thadeu Freitas de Abreu

Exceptional points (EPs) have been suggested for ultra-sensitive sensing because the eigenfrequency splitting grows as the nth-root of a perturbation, suggesting divergent responsivity. In ideal linear devices, however, this responsivity…

Optics · Physics 2025-09-25 Todd Darcie , J. Stewart Aitchison

Scattering of electromagnetic (EM) waves by many small particles (bodies), embedded in a thin layer, is studied. Physical properties of the particles are described by their boundary impedances. The thin layer of depth of the order $O(a)$…

Mathematical Physics · Physics 2011-01-25 A. G. Ramm

The fundamental limit for small antennas provides a guide to the effectiveness of designs. Gustafsson et al, Yaghjian et al, and Mohammadpour-Aghdam et al independently deduced a variation of the Chu-Harrington limit for planar antennas in…

Optics · Physics 2014-02-06 Morteza Shahpari , David V. Thiel , Andrew Lewis

The Chu circuit model provides the basis for analyzing the minimum radiation quality factor, Q, of a given spherical mode. However, examples of electrically large spherical radiators readily demonstrate that this Q limit has limitations in…

Classical Physics · Physics 2024-11-07 Carl Pfeiffer , Bae-Ian Wu

We study the finite frequency (F.F.) noise properties of edge states in the Laughlin state. We investigate the model of a resonant detector coupled to a quantum point contact in the weak-backscattering limit. In particular we discuss the…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 M. Carrega , D. Ferraro , A. Braggio , M. Sassetti

Superconducting microwave resonators are used in many low-power applications, such as the study of two-level system loss in superconducting quantum devices. Fano asymmetry, characterized by a nonzero asymmetry angle $\phi$ in the diameter…

We investigate spontaneous emission from a quantum emitter located within the mode volume of a microring resonator that features chiral exceptional points. We show that this configuration offers enough degrees of freedom to exhibit a full…

Optics · Physics 2021-03-17 Q. Zhong , A. Hashemi , S. K. Ozdemir , R. El-Ganainy

Exceptional points (EPs), singularities of non-Hermitian physics where complex spectral resonances degenerate, are one of the most exotic features of nonequilibrium open systems with unique properties. For instance, the emission rate of…

We show theoretically that the characteristic modes of dielectric resonator antennas (DRAs) must be capacitive in the low frequency limit, and show that as a consequence of this constraint and the Poincar\'{e} Separation Theorem, the modes…

Applied Physics · Physics 2021-08-30 Binbin Yang , Jaewoo Kim , Jacob J. Adams

In this work, a parametric up-converter amplifier is introduced as a wideband impedance matching network for receiving electrically small antennas. Chu's limit restricts the minimum Q-factor of unloaded small antennas; however, the…

Applied Physics · Physics 2021-01-11 Pedram Loghmannia , Majid Manteghi

Enhancing light-matter interactions at the nanoscale is foundational to nanophotonics, with epsilon near zero (ENZ) materials demonstrating significant potential.High-quality (Q) factor resonances maximizing these interactions are typically…