Article
Engineering, Electrical & Electronic
Wanghui Yang, Zhen Peng, Jishan Ren, Jianjun Gao, Guohua Zhai
Summary: This letter proposes and investigates a novel composite right/left-handed leaky-wave antenna (LWA) unit cell with high dispersive behavior. The unit cell, formed by four stubs embedded in a rectangular ring patch, is designed to achieve high scanning rate. The measured results show that the antenna prototype can achieve a seamless scanning angle of 130 degrees within a specific frequency range, indicating a high scanning rate.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Muzhi Gao, Kang Li, Fanmin Kong, Gaoyang Zhu, Huawei Zhuang
Summary: A simple scheme for realizing tunable closed-stopband composite right/left-handed leaky-wave antennas (CRLH LWAs) in the terahertz (THz) range using graphene-based technology is presented. The antennas exhibit frequency-scanning behaviors at THz with narrower bandwidth than conventional graphene-based antennas, showing strong tunable characteristics and improved performance for beam-steering applications at THz.
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Morteza Mohammadi Shirkolaei, Javad Ghalibafan
Summary: This article proposes a scannable leaky-wave antenna that can provide backward, broadside, and forward radiations by change in the operation frequency or the magnetic bias. The results show that the antenna performs well at 6.6 GHz.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Computer Science, Artificial Intelligence
Biswajit Karan, Sitanshu Sekhar Sahu, Juan Rafael Orozco-Arroyave, Kartik Mahto
Summary: This study introduces time-frequency features to detect Parkinson's disease, achieving good classification accuracy in experiments. Results indicate that the proposed method performs well in distinguishing between PD patients and healthy individuals.
COMPUTER SPEECH AND LANGUAGE
(2021)
Article
Engineering, Electrical & Electronic
Ziwei Li, Wenjie Cui, Ruipeng Liu, Kanglong Zhang, Weibo Liang, Mengjun Wang, Chao Fan, Hongxing Zheng, Erping Li
Summary: This article proposes a compact magnetic dipole composite right-/left-handed transmission line leaky-wave antenna that achieves a wide beam-scanning range and compactness by adding alumina ceramic blocks to form the magnetic dipole. Experimental results demonstrate higher antenna gain and wide beam-scanning range stability under compact design conditions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Ruchi Agarwal, R. L. Yadava, Sushrut Das
Summary: This article presents a multilayered circularly polarized leaky-wave antenna based on the composite right/left-handed transmission line concept, which achieves wideband circular polarization, continuous beam scanning capability, and is suitable for X-band radar and satellite applications.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Ruchi Agarwal, Ram Lal Yadava, Sushrut Das
Summary: This study proposes a miniaturized leaky-wave antenna based on substrate-integrated waveguide, which exhibits fast beam scanning. The antenna utilizes the composite right/left-handed property and an inverted Z-shaped slot as the unit cell, allowing continuous frequency beam scanning from -40 degrees to 51 degrees within the impedance bandwidth. It features small size, high peak gain, low sidelobe levels, and is a viable choice for X-band beam scanning applications.
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Donghui Li, Muguang Wang, Yuxiao Guo, Hongqian Mu, Jian Sun, Chuncan Wang, Yandong Gong
Summary: A bandwidth compressed time-mapped spectrogram analysis method based on temporal Talbot effect and temporal magnification is proposed and numerically demonstrated. By sampling, dispersion, and temporal magnification, high-frequency analysis is achieved, effectively improving frequency resolution.
IEEE JOURNAL OF QUANTUM ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Kazuki Terada, Keizo Choi, Naobumi Michishita, Takayoshi Sasaki, Keisuke Sato, Ichiro Oshima, Hiroaki Nakabayashi
Summary: This study investigates the circuit parameters of the unit cell of a composite right-/left-handed rod-shaped leaky wave antenna in order to suppress beam squint caused by frequency fluctuation. It is found that reducing the right-handed circuit parameter values contributes to the suppression of beam squint. Additionally, the beam squint is determined by the ratio of right-handed inductance and left-handed inductance when the CRLH transmission line is formed based on a conventional transmission line, and a ratio condition for minimizing beam squint is derived.
IEICE COMMUNICATIONS EXPRESS
(2022)
Proceedings Paper
Automation & Control Systems
Ruiyuan Ming, Peng Ye, Duyu Qiu, Xuefeng Dai, Zhixiang Pan, Xuetao Liu
Summary: Short-time Fourier transform (STFT) is widely used in electronic measurement and fault diagnosis areas. This study designs an STFT implementation structure that supports high-speed time-frequency analysis and flexible resolution adjustment.
2023 IEEE AUTOTESTCON
(2023)
Proceedings Paper
Acoustics
Maxime Leiber, Axel Barrau, Yosra Marnissi, Dany Abboud
Summary: This paper revisits the usage of spectrograms in neural networks, proposing a continuous parameter optimization approach for the window length instead of using empirically tuned integer hyperparameters. The authors define a differentiable version of the STFT and discuss the impact of the window length on bin position and number. The benefits of this approach are illustrated through estimation and classification tasks, showing its relevance not only to neural networks but also to other STFT-based signal processing algorithms.
2022 30TH EUROPEAN SIGNAL PROCESSING CONFERENCE (EUSIPCO 2022)
(2022)
Article
Optics
Erjun Zhang, Yang Cao, Christoph Caloz, Maksim Skorobogatiy
Correction
Optics
Erjun Zhang, Yang Cao, Christoph Caloz, Maksim S. Korobogatiy
Article
Engineering, Electrical & Electronic
Christophe Caloz, Ari Sihvola
IEEE ANTENNAS AND PROPAGATION MAGAZINE
(2020)
Article
Engineering, Electrical & Electronic
Xiaoyi Wang, Christophe Caloz
Summary: This article introduces the concept of spread-spectrum selective camouflaging based on time-modulated metasurface, where the object covered by the metasurface is perfectly camouflaged to foe radar due to drastic reduction of signal power spectral density, while the friend radar can detect the object using spread-spectrum demodulation key corresponding to the metasurface modulation, with robustness to interfering signals. The proposed system is theoretically analyzed and demonstrated through simulation and experimental results.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Optics
Zoe-Lise Deck-Leger, Xuezhi Zheng, Christophe Caloz
Summary: This paper extends current knowledge on electromagnetic wave scattering from bounded moving media by complementing the dispersion and impedance relations, explaining the phenomenon of double-downstream wave transmission across a stationary interface, generalizing the problem to oblique motion, and highlighting the connection to spacetime modulated media.
Article
Engineering, Electrical & Electronic
Mojtaba Dehmollaian, Christophe Caloz
Summary: This article presents a technique for mapping complex spatial and temporal frequencies of electromagnetic media and structures, utilizing analytical properties and polynomial fitting. It is not only applicable to canonical problems with analytical solutions, but also to general medium or structure problems from full-wave simulation results. The proposed technique is demonstrated on various systems and validated by analytical or simulated results.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Physics, Applied
Ashutosh Patri, Kevin G. Cognee, Louis Haeberle, Vinod Menon, Christophe Caloz, Stephane Kena-Cohen
Summary: Optical antennas made of low-loss dielectrics, known as photonic gap antennas (PGAs), exhibit high quantum efficiency and intensity enhancement due to their unique configuration with high-index pillar structures and low-index gap materials. By optimizing the position of the gap, PGAs can provide unidirectional out-of-plane radiation and enhance spontaneous emission rates by a factor of approximately 1000 for air gaps and approximately 400 for CYTOP gaps across a spectral bandwidth of about 300 nm at a wavelength of 1.25 μm. As receivers, PGAs can also lead to a near-field intensity enhancement by a factor of about 3000 for air gaps and approximately 1200 for CYTOP gaps.
PHYSICAL REVIEW APPLIED
(2021)
Article
Engineering, Electrical & Electronic
Xiaoyi Wang, Christophe Caloz
IEEE ANTENNAS AND PROPAGATION MAGAZINE
(2022)
Article
Engineering, Electrical & Electronic
Mohamad J. Hajiahmadi, Reza Faraji-Dana, Christophe Caloz
Summary: We present a metasurface-based system for microwave hyperthermia treatment of brain tumors, employing a time-reversal technique for optimal focusing. Compared to previous array-based systems, this system offers superior focal resolution and lower complexity and cost.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Physics, Applied
Amir Bahrami, Zoe-Lise Deck-Leger, Christophe Caloz
Summary: Space-time-varying metamaterials based on uniform-velocity modulation have attracted significant attention in the past decade. This paper provides an extensive investigation of accelerated-modulation space-time metamaterials and establishes their electrodynamic principles using the tools of general relativity. The study reveals that an electromagnetic beam propagating in an accelerated-modulation metamaterial is bent, similar to the curvature of spacetime caused by gravitation. The paper also demonstrates the vast potential diversity of accelerated-modulation metamaterials through the illustration of related Schwarzschild holes.
PHYSICAL REVIEW APPLIED
(2023)
Article
Engineering, Electrical & Electronic
Christophe Caloz, Zoe-Lise Deck-Leger, Amir Bahrami, Oscar Cespedes Vicente, Zhiyu Li
Summary: This article presents a global and extended perspective of electrodynamic metamaterials formed by space and time engineered modulations, which we name generalized space-time engineered modulation (GSTEM) metamaterials, or GSTEMs. It discusses the physics and formation of GSTEMs and introduces accelerated metamaterials as an extra type of dynamic metamaterials. The article also explores the potential applications and future prospects of GSTEMs.
IEEE ANTENNAS AND PROPAGATION MAGAZINE
(2023)
Article
Materials Science, Multidisciplinary
Zhiyu Li, Xikui Ma, Amir Bahrami, Zoe-Lise Deck-Leger, Christophe Caloz
Summary: Recent research developments have explored the alteration of fundamental physics phenomena in the presence of spacetime modulation, specifically in the area of spacetime metamaterial structures and systems. This study presents a generalized and comparative description of total internal reflection (TIR) at different dynamic interfaces, including classical interfaces, interfaces formed by electromagnetic modulation, and fixed interfaces between moving-matter media. The study introduces alternative criteria for the critical angle and validates the results using both analytical and full-wave analysis techniques, with potential applications in ultrafast optics, gravity analogs, and quantum processing.
Article
Physics, Multidisciplinary
Galina Nemova, Christophe Caloz
Summary: The proposed method involves using frequency-selective dissipative coupling in a coupled-waveguide structure to reduce the heat generated by CARS reversed cycles in active Raman media. This coupling involves an active Raman waveguide and a dissipative waveguide tuned to the anti-Stokes wavelength, which evacuates anti-Stokes photons to offset the growth of the anti-Stokes signal and suppress the heat generation.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Engineering, Electrical & Electronic
Mojtaba Dehmollaian, Yousef Vahabzadeh, Karim Achouri, Christophe Caloz
IEEE JOURNAL ON MULTISCALE AND MULTIPHYSICS COMPUTATIONAL TECHNIQUES
(2020)
Article
Engineering, Electrical & Electronic
Trevor Brown, Yousef Vahabzadeh, Christophe Caloz, Puyan Mojabi
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2020)
