Article
Optics
Yan Shi, Hao Xuan Meng, Hua Jie Wang
Summary: In this paper, a CMR method is proposed to design a compact metasurface antenna with low RCS in a wideband. By calculating the complex characteristic currents and designing a metasurface subarray with wideband polarization conversion, a rotationally arranged metasurface array is designed for wideband RCS reduction. The miniature metasurface antenna designed by the CMR method demonstrates good broadside radiation pattern and maximal gain with significant RCS reduction in the wide band.
Article
Multidisciplinary Sciences
Theodor S. Becker, Dirk-Jan Van Manen, Thomas Haag, Christoph Baerlocher, Xun Li, Nele Boersing, Andrew Curtis, Marc Serra-Garcia, Johan O. A. Robertsson
Summary: This paper presents a method for achieving active acoustic cloaking and holography without prior knowledge of the wavefield, allowing objects to remain invisible and illusions intact even for broadband moving sources. This opens up previously inaccessible research directions and facilitates practical applications such as architectural acoustics, education, and stealth.
Article
Physics, Applied
Junjie Zhan, Yujian Mei, Kai Li, Yi Zhou, Jian Chen, Yungui Ma
Summary: In this work, a bi-physical metamaterial invisible coating technique is proposed, which can effectively hide underwater objects from being detected via both magnetic fields and acoustic waves. This technique has the potential for important applications in military and civilian fields.
APPLIED PHYSICS LETTERS
(2022)
Article
Astronomy & Astrophysics
Yong-Hui Lin, Hans-Werner Hammer, Ulf-G Meissner
Summary: We predict the differential cross sections for e(-)p and e(+)p elastic scattering in the PRad-II energy region. The sensitivity of the cross sections to two-photon exchange effects is investigated, and it is found that the differences between model calculations and phenomenological extractions of two-photon corrections cannot be resolved if the uncertainty in the form factors is taken into account.
Article
Acoustics
Hao Zhang, Jin He, Chongrui Liu, Fuyin Ma
Summary: In this paper, a design method for an acoustic invisibility cloak based on subwavelength metasurfaces is proposed to achieve wideband stealth performance. It overcomes the limitations of narrowband and high directional dependence of previous cloaks, and has wide engineering applications.
Article
Multidisciplinary Sciences
Mansour Zaremanesh, Ali Bahrami
Summary: This study proposes a concentric cylindrical cloak structure for achieving acoustic cloaking phenomenon. By optimizing the shell design and using a composite lattice structure, the scattering of objects can be greatly reduced, simplifying the fabrication process of cloaking shells.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Analytical
Zeyang Zhou, Jun Huang
Summary: The study found that the opening action of the spoiler will compromise the stealth characteristics of the aircraft, affecting different azimuth angles and elevation angles, with the smooth dynamic deflection mode being conducive to reducing the radar cross-section of the aircraft.
Article
Physics, Applied
Farhang Loran, Ali Mostafazadeh
Summary: This study provides a precise characterization of a higher-dimensional generalization of the unidirectional invisibility effect and identifies the conditions for its realization in scalar and electromagnetic wave scattering. The approach allows for the construction of potentials and linear dielectric media that exhibit perfect directional invisibility in a finite frequency domain.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Zeeshan A. Awan, Divitha Seetharamdoo
Summary: This article presents an analysis on the enhancement of backscattering radar cross section from an equivalent human body cylinder using a specific type of coating. The study shows that inductive meta surface and inductive meta surface followed by a dielectric layer coatings cannot be used to enhance the backscattering radar cross section, but an epsilon negative metamaterial coating with specific permittivity and thickness can significantly enhance the backscattering radar cross section of the human body under oblique incidence.
IET MICROWAVES ANTENNAS & PROPAGATION
(2022)
Article
Chemistry, Analytical
Zeyang Zhou, Jun Huang
Summary: The study used a dynamic analysis approach to investigate the radar signature of a tandem helicopter in the X-band, finding that various factors have significant effects on the helicopter's radar cross-section. A larger elevation angle within a given observation angle range is undesirable for helicopter stealth.
Article
Optics
Yichao Liu, Fei Sun, Yibiao Yang, Yuying Hao, Shaowei Liang, Zheng Wang
Summary: A full space omnidirectional cloak is designed by thrice coordinate transformations inside the optic-null medium (ONM) shell. The cloak can be realized using subwavelength dielectric channels and metallic plates, along with a uniform dielectric restoring core in air, without the need for metamaterials or waveguide structures. The electromagnetic parameters of the cloak are strict in accordance with transformation optics, resulting in a nearly perfect omnidirectional cloaking effect achieved by natural materials at the design frequency. The shape, size, and position of the concealed region can be freely adjusted due to the transformation-invariant feature of the ONM.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Yong Pan, Lun Huang, Wei Sun, Dangli Gao, Long Li
Summary: An anti-near-infrared detection CoGaZnSe multilayer film was designed and prepared using pulsed laser deposition technology, successfully reducing the quantum efficiency of infrared detection and showing a significant effect on wool materials. This research offers new ideas and methods for stealth technology and materials, enhancing the efficiency of anti-infrared detection and potential applications in military, detection, and stealth technology.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Astronomy & Astrophysics
Jingle B. Magallanes, Jinky B. Bornales, Rene Luna-Garcia
Summary: The study fitted the angular-averaged differential cross section of elastic electron-proton scattering using modified scatterings, revealing an energy-decaying ratio of -2.8 and a diminishing cloud layer effect. The models for spin bare mass and spin effective mass favored those with additional considerations, with the spin with other criteria effective mass model being the most preferred in general.
Article
Physics, Multidisciplinary
Cheng-Fu Yang, Li-Jun Yun, Jun-Wei Li
Summary: A reusable reciprocal invisibility and phantom device is proposed and designed based on multi-folded transformation optics and equivalent components. The device has homogeneous material parameters and does not require any anti-object to hide the target, breaking through the limitations of previous reciprocal cloak designs. The device also has a perfect illusion effect, which can confuse detection radars while hiding the target. Additionally, the open structure of the device allows the target object to exchange materials and transfer information with the outside world, enabling stealth or phantom of new target objects without changing any parameters of the device.
Article
Computer Science, Information Systems
Rachel E. Jarvis, Jay W. McDaniel
Summary: This paper discusses the challenges of RCS measurements at W-band and proposes techniques to overcome these challenges for accurate measurements. By combining S-11 measurements with post-processing algorithms, RCS values are extracted using a single antenna. The proposed techniques are evaluated using a Vector Network Analyzer and frequency extender. The experiments demonstrate the feasibility of these techniques and their compatibility with existing hardware configurations.
Article
Optics
Grigorii Ptitcyn, Aristeidis Lamprianidis, Theodosios Karamanos, Viktar Asadchy, Rasoul Alaee, Marvin Mueller, Mohammad Albooyeh, Mohammad Sajjad Mirmoosa, Shanhui Fan, Sergei Tretyakov, Carsten Rockstuhl
Summary: This article explores the interaction between light and time-varying media, which not only provides fundamental insights but also opens up possibilities for various practical applications. Time modulation is a fundamental tool for controlling light in different ways, especially for complex systems with both spatial and temporal structures. The article develops and applies a self-consistent analytical theory of light scattering, focusing on a sphere made from a time-varying material with Lorentzian dispersion. The proposed theory is verified through full-wave simulations and reveals interesting effects such as energy transfer from the time-modulation subsystem to the electromagnetic field.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Mohammad Sajjad Mirmoosa, Xuchen Wang, Lukas Freter, Ari Sihvola, Sergei Tretyakov
Summary: Generalized duality transformations modify constitutive relations of electromagnetic media while preserving principal electromagnetic properties. In this work, we consider the transformation of Tellegen nihility as a specific type of extreme-property nonreciprocal bi-isotropic media and demonstrate that intriguing electromagnetic properties of that medium can be realized in a certain class of isotropic magnetodielectric media without magnetoelectric coupling. We show that the transformed medium exhibits permittivity and permeability values with equal absolute values and opposite signs.
Article
Nanoscience & Nanotechnology
Xuchen Wang, Mohammad S. S. Mirmoosa, Sergei A. A. Tretyakov
Summary: This paper theoretically elucidates the effect of temporal discontinuities of effective parameters on the propagation of reactive metasurface surface waves. It shows that by switching the surface reactance value, the velocity of surface waves can be fully controlled, and the power of reflected and transmitted waves can be amplified. It also demonstrates that switching a boundary from supporting transverse-electric polarization to only allowing transverse-magnetic polarization freezes and converts the propagating surface wave to a static magnetic-field distribution. Furthermore, temporal jumps of the boundary reactance couple free-space propagating waves to the surface wave, similar to a spatial prism. These intriguing phenomena enable the generation and control of surface waves.
Article
Physics, Applied
J. A. Alvarez-Sanchis, B. Vidal, S. A. Tretyakov, A. Diaz-Rubio
Summary: By controlling geometric parameters, the quality factor of all-dielectric metasurfaces can be adjusted and designed theoretically for improved performance as sensors in the THz band. However, material losses significantly limit the resonances' quality factor, leading to the proposal of all-dielectric metasurfaces as an alternative to metal-dielectric structures. In this study, the effect of losses on all-dielectric metasurfaces is examined using realistic materials, and their sensing performance is compared with nanostructures supporting extraordinary optical transmission. The results highlight the limitations of all-dielectric metasurfaces and the superiority of structures with extraordinary optical transmission.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Applied
Hamidreza Taghvaee, Fu Liu, Ana Diaz-Rubio, Sergei Tretyakov
Summary: Breaking the diffraction limit on optical devices and achieving subwavelength focusing requires tailoring the evanescent spectrum of wave fields. This paper presents a feasible strategy based on the concepts of the perfect lens and power flow-conformal metasurfaces, allowing for subwavelength hotspot size in near-field focusing. The findings have potential applications in antennas, beam-shaping devices, nonradiative wireless power transfer systems, microscopy, and lithography.
PHYSICAL REVIEW APPLIED
(2023)
Article
Engineering, Electrical & Electronic
Sergei Kosulnikov, Francisco S. Cuesta, Xuchen Wang, Sergei A. Tretyakov
Summary: Reconfigurable Intelligent Surfaces (RISs) are promising tools for optimizing propagation channels in advanced wireless communication systems, particularly in high-frequency (millimeter-band) links with directive antennas. RIS panels act as high-gain passive repeaters, creating complex field patterns in the far zone through interference with reflected waves from illuminated spots on supporting walls. In this study, we develop a simple link-budget model for non-line-of-sight (NLOS) channels using reflections from finite-size metasurfaces (MSs) designed as anomalous reflectors or splitters. The model considers diffraction at RIS panel edges and interference with reflections from supporting structures, taking into account realistic losses and validating results through numerical simulations.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Nanoscience & Nanotechnology
Mohamed Hesham Mohamed Mostafa, Mohammad S. Mirmoosa, Sergei A. Tretyakov
Summary: Recently, there has been extensive research on temporally varying electromagnetic media to explore new ways of controlling light. However, spin-dependent phenomena in these media have not been thoroughly investigated. In this study, we demonstrate the existence of spin-dependent phenomena at a temporal interface between chiral and dielectric media. We show that linearly polarized light is split into right-handed and left-handed circularly polarized waves with different angular frequencies and the same phase velocities due to the material discontinuity in time. This effect allows for high-efficiency temporal separation of the two spin states of light.
Article
Multidisciplinary Sciences
Xuchen Wang, Mohammad Sajjad Mirmoosa, Viktar S. Asadchy, Carsten Rockstuhl, Shanhui Fan, Sergei A. Tretyakov
Summary: Photonic time crystals are artificial materials with spatially uniform but temporally varying electromagnetic properties. This study extends the concept of photonic time crystals to two-dimensional artificial structures called metasurfaces. By designing a microwave metasurface, the researchers confirmed the existence of momentum bandgaps and exponential wave amplification, demonstrating the potential of metasurfaces as a material platform for emerging photonic space-time crystals and for amplifying surface-wave signals in wireless communications.
Article
Physics, Applied
N. Ha-Van, C. R. Simovski, F. S. Cuesta, P. Jayathurathnage, S. A. Tretyakov
Summary: In conventional inductive wireless power devices, energy is transferred via reactive near fields, and radiation from transmitting and receiving coils is considered a parasitic effect that reduces power-transfer efficiency. This paper develops a dynamic theory of wireless power transfer between two small loop antennas, clarifies the role of far-field radiation, and proposes a possibility to achieve efficient wireless power transfer at large distances through radiation suppression. The analytical results are validated through simulations and measurements, offering the potential to greatly expand the distance range of compact wireless power-transfer devices.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Applied
G. A. Ptitcyn, M. S. Mirmoosa, S. Hrabar, S. A. Tretyakov
Summary: Temporal modulation allows dynamic control and modification of electromagnetic system response, enabling functionalities that were conventionally unachievable. By explicitly considering the time dependence of circuit or surface parameters, it becomes possible to emulate electromagnetic systems with arbitrary frequency dispersion and nonlinear properties, including non-Foster response. Proper modulation of a time-varying capacitor can mimic static inductance, capacitance, or resistance with arbitrary values, positive or negative. The stability of the system is ensured through necessary modifications of determined ideal modulation functions. A proposed invisible sensor is demonstrated using full-wave simulations, along with discussions on the stability of externally modulated systems. This study introduces an alternative paradigm of using time modulations to engineer system responses, applicable not only to electromagnetic systems but also in other branches of physics.
PHYSICAL REVIEW APPLIED
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Sergei Kosulnikov, Francisco S. Cuesta, Xuchen Wang, Ana Diaz-Rubio, Sergei Tretyakov
Summary: High-frequency wireless communications at millimeter-wave bands require directive, high-gain antennas to achieve longer communication links. Anomalously reflecting and reconfigurable intelligent surfaces can be used to ensure sufficient space coverage. This presentation discusses recent analytical estimations of link budget with the presence of such reflectors, providing simple expressions for the far field using macroscopic reflection coefficients and a generalized Friis formula. The analytical results are validated through numerical simulations of a specific realization for millimeter-wave frequency band.
2023 17TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, EUCAP
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yongming Li, Xikui Ma, Grigorii Ptitcyn, Sergei Tretyakov
Summary: In this study, a novel method is proposed for designing anomalous reflectors using arrays of loaded strips. By assuming two different sets of induced polarization currents flowing on the surface, specular reflection can be eliminated and the reflected wave propagates towards the desired direction. Surface waves are tuned by optimizing the current distribution to obtain purely reactive loads. Additional loaded strips inserted within a lambda/2-sized cell of the structure help optimize the design, and perfect anomalous reflection is achieved. The obtained results are compared with conventional reflectarrays, demonstrating significant improvement.
2023 17TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, EUCAP
(2023)
Article
Materials Science, Multidisciplinary
F. S. Cuesta, M. S. Mirmoosa, S. A. Tretyakov
Summary: One advantage of reciprocal bianisotropic metasurfaces is their ability to produce asymmetric scattering depending on the illumination side and circular polarization. However, we demonstrate that geometrical asymmetry can be emulated using nonbianisotropic layers in coherent illumination, enabling optical control of desired asymmetric scattering and chirality effects. We illustrate this concept by emulating asymmetric scattering required for creating a 180 degrees hybrid junction for plane waves using either a bianisotropic metasurface or simple sheets with electric response under simultaneous illumination by two coherent waves.
Proceedings Paper
Engineering, Electrical & Electronic
Nam Ha-Van, Constantin R. Simovski, Francisco S. Cuesta, Prasad Jayathurathnage, Sergei A. Tretyakov
Summary: We investigate a regime of radiation suppression in wireless power transfer (WPT) between two loop antennas in free space. By optimizing load impedance and working frequency, high power transfer efficiency can be achieved due to partial compensation of the radiation resistances of both antennas. This regime is analyzed for two antenna arrangements: coaxial arrangement, where WPT is solely based on near fields, and coplanar arrangement, where both near-field and far-field power transfer mechanisms are combined. The radiation suppression regime is analyzed and visualized for both arrangements. Theoretical results are validated by simulations and experiments with two loop antennas.
2023 53RD EUROPEAN MICROWAVE CONFERENCE, EUMC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Shamsul Arefeen Al Mahmud, Prasad Jayathurathnage, Yining Liu, Jorma Kyyra
Summary: Fast automatic identification of WPT receiver is critical for future deployment of efficient and low-cost dynamic wireless power transfer devices. This article presents a new approach for receiver identification and transmitter activation in wireless power transfer systems, enabling fast charging request and energy-saving.
2023 IEEE WIRELESS POWER TECHNOLOGY CONFERENCE AND EXPO, WPTCE
(2023)