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Several basic properties of homogeneous planar Whispering Gallery dielectric resonators are investigated through a general approach. In particular the values for the minimum and maximum allowed radius, defined by irradiation and dielectric…

Instrumentation and Detectors · Physics 2007-05-23 G. Annino , M. Cassettari , M. Martinelli

We present an approach for improving spatial frequency sampling in active incoherent millimeter-wave (AIM) imaging systems using frequency diversity. AIM imaging relies on active transmission of spatio-temporally incoherent signals to…

Signal Processing · Electrical Eng. & Systems 2025-03-12 Jorge R. Colon-Berrios , Jeffrey A. Nanzer

We consider the phenomenon of weak localization of a short wave pulse in a quasi-1D disordered waveguide. We show that the long-time decay of the average transmission coefficient is not purely exponential, in contradiction with predictions…

Disordered Systems and Neural Networks · Physics 2007-05-23 S. E. Skipetrov , B. A. van Tiggelen

Millimeter wave (mmWave) communication in typical wearable and data center settings is short range. As the distance between the transmitter and the receiver in short range scenarios can be comparable to the length of the antenna arrays, the…

Signal Processing · Electrical Eng. & Systems 2019-07-12 Nitin Jonathan Myers , Jarkko Kaleva , Antti Tölli , Robert W. Heath

We are interested in a time harmonic acoustic problem in a waveguide with locally perturbed sound hard walls. We consider a setting where an observer generates incident plane waves at $-\infty$ and probes the resulting scattered field at…

Analysis of PDEs · Mathematics 2017-09-19 Anne-Sophie Bonnet-Ben Dhia , Lucas Chesnel , Sergei A. Nazarov

Pinching-antenna systems have emerged as a promising flexible-antenna architecture for next-generation wireless networks, enabling enhanced adaptability and user-centric connectivity through antenna repositioning along waveguides. However,…

Signal Processing · Electrical Eng. & Systems 2025-07-01 Yanqing Xu , Zhiguo Ding , Robert Schober , Tsung-Hui Chang

Modulation instability in a nonlinear optical waveguide array with alternating positive and negative refractive indices is investigated analytically. Particular solutions of a system of coupled nonlinear equations are found. These solutions…

Pattern Formation and Solitons · Physics 2014-09-30 A. A. Dovgiy , A. I. Maimistov

Band-resolved frequency modulation spectroscopy is a common method to measure weak signals of radiative ensembles. When the optical depth of the medium is large, the signal drops exponentially and the technique becomes ineffective. In this…

A number of new and planned radio telescopes will consist of large arrays of low-gain antennas operating at frequencies below 300 MHz. In this frequency regime, Galactic noise can be a significant or dominant contribution to the total…

Instrumentation and Methods for Astrophysics · Physics 2012-04-23 Steven W. Ellingson

The paper is devoted to the usage of nearfield acoustic holography methods for estimating far field of the object. An experiment was carried out in anechoic chamber. First, acoustic filed was recorded in a plane that was close to source.…

Audio and Speech Processing · Electrical Eng. & Systems 2018-12-11 Mikhail B. Salin , Dmitrii A. Kosteev

This paper presents a paraxial modeling approach for vibro-acoustography, a high-frequency ultrasound imaging technique that makes use of the excited low-frequency field to achieve a higher resolution while avoiding speckles. We start from…

Numerical Analysis · Mathematics 2023-10-06 Teresa Rauscher

The acoustic dispersion properties of monodimensional waveguide filters can be assessed by means of the simple prototypical mechanical system made of an infinite stack of periodic massive blocks, connected to each other by elastic joints.…

Applied Physics · Physics 2019-02-15 Andrea Bacigalupo , Luigi Gambarotta , Marco Lepidi , Francesca Vadalà

Wavefront shaping techniques allow waves to be focused on a diffraction-limited target deep inside disordered media. To identify the target position, a guidestar is required that typically emits a frequency-shifted signal. Here we present a…

Applied Physics · Physics 2025-05-13 Antton Goïcoechea , Jakob Hüpfl , Stefan Rotter , François Sarrazin , Matthieu Davy

The integration density of photonic integrated circuits has been limited by light coupling between waveguides. Traditional approaches to layout the waveguide with high density are based on refractive index engineering to suppress the light…

In a realistic wireless environment, the multi-antenna channel usually exhibits spatially correlation fading. This is more emphasized when a large number of antennas is densely deployed, known as holographic massive MIMO (multiple-input…

Information Theory · Computer Science 2022-02-03 Özlem Tuğfe Demir , Emil Björnson , Luca Sanguinetti

This paper presents an application of time-frequency methods to characterize the dispersion of acoustic waves travelling in a one-dimensional periodic or disordered lattice made up of Helmholtz resonators connected to a cylindrical tube.…

Classical Physics · Physics 2009-07-10 Olivier Richoux , Claude Depollier , Jean Hardy

Designing a new class of rectangular two-dimensional sparse array to enhance the signal resolving capabilities with a limited number of sensors has always been a challenge. We explore the non-uniformity of the sparse arrays to enhance the…

Signal Processing · Electrical Eng. & Systems 2022-06-09 Kretika Goel , Monika Aggarwal , Subrat kar

Acoustic holography in the megahertz frequency range can impact numerous applications, including manufacturing, non-destructive testing, and transcranial ultrasound. However, designing lens topologies for complex acoustic holograms in the…

Applied Physics · Physics 2025-08-26 Pradosh Pritam Dash , Costas D. Arvanitis

Loudspeaker array beamforming is a common signal processing technique for acoustic directivity control and robust audio reproduction. Unlike their microphone counterpart, loudspeaker constraints are often heterogeneous due to arrayed…

Sound · Computer Science 2024-11-26 Yuancheng Luo

A large number of deep and wide-field radio interferometric surveys are being designed to measure accurate statistics of faint source populations. Most require mosaic observations, and expect to benefit from the sensitivity provided by…

Instrumentation and Methods for Astrophysics · Physics 2014-03-21 Urvashi Rau , Sanjay Bhatnagar , Frazer N. Owen