Article
Computer Science, Information Systems
Gang Wang, Ruichao Zheng, K. C. Ho
Summary: This paper investigates the elliptic localization problem for moving objects using time delay and Doppler frequency shift measurements. The authors propose a method to jointly estimate the positions, velocities, and offsets of the object and the transmitter. They formulate the problem as a non-convex weighted least squares problem and apply semidefinite relaxation to obtain a convex solution. The theoretical analysis shows that using multiple transmitters can improve performance, and the proposed method achieves high accuracy under small Gaussian noise conditions.
IEEE TRANSACTIONS ON MOBILE COMPUTING
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Hua Chen, Zhenqi Chen, Rongde Ou, Run Chen, Zhaohui Wu, Bin Li
Summary: This paper presents a UWB digital transmitter that complies with the IEEE 802.15.4z standard and features reconfigurable pulse-shaping. The proposed technique utilizes programmable delay lines to achieve high spectrum efficiency and significant sidelobe suppression. The prototype chip, implemented in a 28nm CMOS process, operates from 4 to 9 GHz with programmable signal bandwidths and meets the IEEE 802.15.4z standard.
2022 IEEE RADIO FREQUENCY INTEGRATED CIRCUITS SYMPOSIUM (RFIC)
(2022)
Proceedings Paper
Acoustics
Ruichao Zheng, Gang Wang, K. C. Ho, Lei Huang
Summary: This paper addresses the multistatic localization of a moving object using time delay and Doppler frequency shift measurements. A non-convex weighted least squares problem is formulated and solved using convex semidefinite relaxation. The simulation results show that the proposed method achieves high accuracy and outperforms existing methods under mild Gaussian noise conditions.
2022 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Sang-Woo Seo, SeungJoon Kwon
Summary: This study introduces a novel technique for hand pose and position estimation using ultrasonic and inertial sensors, which combines ultrasonic-based rough positioning with inertial sensor-based accurate real-time measurement.
12TH INTERNATIONAL CONFERENCE ON ICT CONVERGENCE (ICTC 2021): BEYOND THE PANDEMIC ERA WITH ICT CONVERGENCE INNOVATION
(2021)
Article
Engineering, Electrical & Electronic
Christophe Caloz, Ari Sihvola
IEEE ANTENNAS AND PROPAGATION MAGAZINE
(2020)
Article
Engineering, Electrical & Electronic
Trevor Brown, Chaitanya Narendra, Yousef Vahabzadeh, Christophe Caloz, Puyan Mojabi
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2020)
Article
Engineering, Electrical & Electronic
Christophe Caloz, Zoe-Lise Deck-Leger
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2020)
Article
Engineering, Electrical & Electronic
Christophe Caloz, Zoe-Lise Deck-Leger
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2020)
Correction
Optics
Erjun Zhang, Yang Cao, Christoph Caloz, Maksim S. Korobogatiy
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)
