Article
Engineering, Electrical & Electronic
Cahya Edi Santosa, Josaphat Tetuko Sri Sumantyo, Steven Gao, Koichi Ito
Summary: This article introduces a novel broadband circularly polarized microstrip array antenna for synthetic aperture radar system onboard Cessna 172 Aircraft. The antenna design includes a unique array formation and element layout to achieve broadband circular polarization, improved gain, wide impedance bandwidth, and high aperture efficiency. The prototype antenna demonstrates impressive performance in terms of bandwidth, axial ratio, gain, and beamwidth.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Mei Li, Zhehao Zhang, Ming-Chun Tang, Lei Zhu, Neng-Wu Liu
Summary: A new design method is proposed to significantly expand the axial ratio bandwidth of a single-fed, low-profile circularly polarized antenna. By optimizing the design of the patches, cross slot, and top-loaded monopole, a wider circular polarization bandwidth is achieved.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Yasunori Yagi, Hirofumi Sasaki, Takayuki Yamada, Doohwan Lee
Summary: A dual-polarized orbital angular momentum multiple-input.multiple-output (OAM-MIMO) system using uniform circular arrays (UCAs) achieved a transmission rate of over 200 Gb/s. By utilizing Butler matrices and polarization multiplexing, multiple OAM modes can be generated and separated to enhance transmission capacity.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Hisato Kashihara, Josaphat Tetuko Sri Sumantyo, Yuta Izumi, Koichi Ito, Steven Gao, Kazuteru Namba
Summary: Recently, unmanned aerial vehicles onboard synthetic aperture radar (UAV-SAR) have been developed for high-resolution, real-time data acquisition and local emergency observation. Our research group plans to develop a circularly polarized UAV-SAR using a 25 kg payload for disaster and environmental monitoring. We proposed a $4\times4$ ax-shaped radiator array antenna with high gain, broadband, and good antenna isolation and axial ratio. The antenna was simulated, fabricated, and measured in an anechoic chamber. The experimental results confirmed the performance of the circularly polarized SAR.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Sai Radavaram, Saininad Naik, Maria Pour
Summary: The study addresses the polarization instability issue at high frequencies in U-slotted wideband antennas by utilizing the TM12 mode in circular patch antennas. The proposed antenna offers stable polarized waves over a wide frequency range and achieves desired impedance and radiation characteristics by integrating U-slots, shorting vias, and non-resonating arc slits. The antenna’s polarization stability is demonstrated through surface current distributions, radiation patterns, and x- and y-polarized gains across the frequency range of interest.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Hongcai Yang, Xiongying Liu, Yi Fan, Liping Xiong
Summary: The study introduces a dual-circular polarization textile antenna for wearable applications, utilizing a polarization rotation artificial magnetic conductor to enable dual-CP radiation. The antenna design demonstrates robust performance under lossy conditions and deformation.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Ehsan Koohkan, Saughar Jarchi, Ayaz Ghorbani, Mohammad Bod
Summary: In this letter, a helical slot antenna is proposed for generating multiple orbital angular momentum (OAM) modes. The antenna consists of four concentric helical slot array antennas, excited by an annular microstrip line. Different circularly polarized OAM modes of 0, -1, -2, and -3 at 3.5 GHz frequency with more than 10% fractional bandwidth are achieved by selecting the number of each helical slot and length of microstrip feed. The proposed compact antenna, with a diameter of 89 mm and height of 19.1 mm, has been fabricated and shows promising results in producing different vortex modes.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Bin Xi, Yu Xiao, Yuanxin Li, Zhixi Liang, Shao Yong Zheng, Zengping Chen, Yunliang Long
Summary: This communication presents a periodic mirror-reflected circular-polarized leaky wave antenna with dual-beam scanning in dual polarization types. The antenna unit cell employs two orthogonally separated oblique stubs to create circular polarization. A new method of adding a groove at the junction of stubs within the unit cell is introduced to improve the axial ratio and beam-scanning characteristics. To achieve dual-beam scanning in dual circular polarization, a metallic via is added at the end of the antenna for mirror reflection. The measured results show good agreement with the simulated ones, demonstrating the effectiveness of the proposed antenna design.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Computer Science, Information Systems
Kang Ding, Yanjie Wu, Kun-Hua Wen, Duo-Long Wu, Jian-Feng Li
Summary: This paper investigates a stacked circular polarization (CP) patch antenna design with broad impedance bandwidth, axial-ratio (AR) bandwidth, and flat gains. By introducing a new structure, the design achieves advantages of wide bandwidth, compact size, and flat gain compared to other similar CP stacked patch antennas.
Article
Engineering, Electrical & Electronic
Yara Ashraf Kamel, Hesham A. Mohamed, Hala ELsadek, Hadia Mohamed ELhennawy
Summary: This letter presents a triple-band antenna with CP behavior for bio-telemetry applications. The designed implantable antenna exhibits CP behavior at the Industrial, Scientific, and Medical bands as well as the midfield band. The compact size of the antenna is 50.8 mm³. Specific absorption rate and link margin calculations are included for health safety and reliable communication considerations.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Engineering, Electrical & Electronic
J. Melendro-Jimenez, P. Sanchez-Olivares, A. Tamayo-Dominguez, X. Sun, J. M. Fernandez-Gonzalez
Summary: This paper presents a design of a circularly polarized perforated gradient index (GRIN) flat lens antenna with directive beam-steering properties for millimeter-wave applications. The lens, fed by an open-ended square waveguide (SWG), enhances radiation in a specific direction and generates a high-directivity beam with planar wavefront. The integration of a dielectric polarizer allows the conversion of a linearly polarized incident wave to a circularly polarized emitted wave. The lens and polarizer are manufactured using stereolithography (SLA) 3-D printing technology, and the measured results demonstrate a wide axial ratio bandwidth of 20.58% and an aperture efficiency ranging from 57.34% to 90.32%.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Weixu Yang, Ke Chen, Xinyao Luo, Kai Qu, Junming Zhao, Tian Jiang, Yijun Feng
Summary: A novel high-efficiency polarization-selective bifunctional metasurface has been proposed, which can selectively manipulate left-handed and right-handed circularly polarized light. Through numerical simulations and experiments, it has been shown that the proposed metasurface can be applied to high-gain antennas in millimeter-wave communication systems.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Computer Science, Information Systems
Hoang Dang Cuong, Minh-Thuy Le, Nguyen Quoc Dinh, Xuan Nam Tran, Naobumi Michishita
Summary: In this work, a simple but novel method for modelling PIN diode SMP-1340-040 is developed by using waveguides and modified simulation approaches. Based on the obtained model, a broadband 1-bit unit cell using only one substrate is also proposed. The experimental results show an excellent agreement with the simulation, confirming the accuracy of the proposed PIN diode model.
Article
Engineering, Electrical & Electronic
Wen-Hai Zhang, Quan Xue, Wanchen Yang, Wenquan Che, Shaowei Liao, Haidong Chen, Wenjie Feng, Kam-Weng Tam
Summary: A planar bidirectional circularly polarized antenna using orthogonal magnetic dipoles (OMDs) without an extra phase shift line is proposed. Experimental results show that the antenna has low design complexity and improved gains.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Zimu Zhang, Yongzhi Cheng, Hui Luo, Fu Chen
Summary: This paper proposes a wideband circular polarization metasurface antenna, consisting of a centrosymmetric structure with a mode suppressor and an asymmetric aperture-coupled feed structure separated by dielectric substrates. Two orthogonal modes with a 90 degrees phase difference are excited by an L-shaped slot and a microstrip line in the aperture-coupled feed structure to achieve CP radiation. Two methods are proposed to expand the CP bandwidth: directly suppressing the characteristic mode and indirectly suppressing it using a mode suppressor. The fabricated antenna shows a low profile of ?(0) x ?(0) x 0.075 ?(0) at 5 GHz, with a 3 dB axial ratio bandwidth of 45.2% (4.1-6.5 GHz), an impedance bandwidth of 41.8% (4.1-6.31 GHz), and a peak gain of 7.94 dBic at 5.9 GHz.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Environmental Sciences
Rodrigo E. Alva, Luis G. Pujades, Ramon Gonzalez-Drigo, Guido Luzi, Oriol Caselles, Luis A. Pinzon
Article
Environmental Sciences
Hugo Carreno-Luengo, Guido Luzi, Michele Crosetto
Article
Environmental Sciences
Niccolo Dematteis, Daniele Giordan
Summary: Digital Image Correlation (DIC) is a widely-used technique in geoscience and natural hazard studies to measure surface deformations of various geophysical phenomena. Through analyzing different correlation functions and image representations, as well as studying the impact of various noise sources, findings revealed certain methods are more sensitive to noise, while a newly developed similarity function, DOT, demonstrated strong resistance against different noise sources.
Article
Engineering, Geological
Davide Notti, Aleksandra Wrzesniak, Niccolo Dematteis, Piernicola Lollino, Nunzio Luciano Fazio, Francesco Zucca, Daniele Giordan
Summary: In November 2016, extreme rainfall in the Ligurian Alps of NW Italy triggered landslides and debris flows in the upper Tanarello stream basin, severely damaging the village of Monesi di Mendatica. Utilizing a multidisciplinary approach, researchers defined the landslide behavior, triggering conditions, and chronological evolution leading to the 2016 event, enhancing understanding of the landslide and potential future evolution.
Article
Chemistry, Analytical
Guido Luzi, Pedro F. Espin-Lopez, Fermin Mira Perez, Oriol Monserrat, Michele Crosetto
Summary: The use of radar interferometric techniques in non-urban areas can be challenging due to the lack of stable natural targets, but this can be partially compensated by installing reference targets. Passive corner reflectors (PCRs) are effective but suffer from drawbacks like being cumbersome and weather-sensitive, while active reflectors (AR) provide a less cumbersome alternative with stable phase response. This paper describes the design, implementation, and testing of an AR prototype aimed at providing a fair performance/cost benefit in areas with hard accessibility.
Article
Environmental Sciences
Niccolo Dematteis, Daniele Giordan, Fabrizio Troilo, Aleksandra Wrzesniak, Danilo Godone
Summary: Researchers in the Ferret Valley have conducted long-term monitoring of glacier instability, explored various monitoring methods, identified the monitoring performance and potential of various systems, and proposed data integration strategies.
Article
Computer Science, Interdisciplinary Applications
Niccolo Dematteis, Daniele Giordan, Bruno Crippa, Oriol Monserrat
Summary: The local adaptive multiscale image matching algorithm (LAMMA), which reduces the number of calculations in traditional methods, is applied to measure glacier flow in the Southern Patagonian Icefield, demonstrating its efficiency in computation and outlier displacement. The algorithm shows comparable runtime efficiency to frequency-based methods.
COMPUTERS & GEOSCIENCES
(2022)
Article
Engineering, Geological
Niccolo Dematteis, Aleksandra Wrzesniak, Paolo Allasia, Davide Bertolo, Daniele Giordan
Summary: In the field of landslide monitoring, assessing the spatially-distributed three-dimensional surface displacement is crucial but challenging. This study presents a methodology that combines robotic total station measurements and digital image correlation to achieve spatially-distributed three-dimensional surface displacement. The developed method shows promising results and can be easily implemented using lowcost portable field equipment.
ENGINEERING GEOLOGY
(2022)
Article
Engineering, Civil
D. Gisolo, M. Previati, I. Bevilacqua, D. Canone, M. Boetti, N. Dematteis, J. Balocco, S. Ferrari, A. Gentile, M. N'sassila, B. Heery, H. Vereecken, S. Ferraris
Summary: Ecosystems in the Alps are challenging to measure and model due to their complex morphology and the limited availability of information. This study proposes a radiation-driven hydrological model for predicting actual evapotranspiration and estimating soil-water balance, which has been validated and performs well for mountain grassland.
JOURNAL OF HYDROLOGY
(2022)
Article
Geosciences, Multidisciplinary
Niccolo Dematteis, Daniele Giordan, Paolo Perret, Melchior Grab, Hansruedi Maurer, Fabrizio Troilo
Summary: This research investigates the influence of bedrock geometry on glacier surface morphology through measurements of ice thickness, detection of bedrock topography, and analysis of glacier surface morphology and kinematics. The findings highlight the importance of frequent monitoring of glacier morphology for accurate glacier hazard assessment.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Remote Sensing
Guido Luzi, Anna Barra, Qi Gao, Pedro F. Espin-Lopez, Riccardo Palama, Oriol Monserrat, Michele Crosetto, Xavier Colell
Summary: A C-band low-cost active reflector was tested in an experimental campaign for monitoring a landslide-threatened area. With a network of passive corner reflectors and one active reflector installed along a forested slope, interferograms were processed to evaluate area stability. Despite temperature sensitivity, the active reflector operated with acceptable stability for deformation retrieval in monitoring purposes.
REMOTE SENSING LETTERS
(2022)
Editorial Material
Environmental Sciences
Daniele Giordan, Guido Luzi, Oriol Monserrat, Niccolo Dematteis
Article
Geochemistry & Geophysics
Niccolo Dematteis, Daniele Giordan, Bruno Crippa, Oriol Monserrat
Summary: Measuring glacier elevation change is crucial for various purposes, such as estimating glacier mass balance, calibrating climate models, and assessing the impact of global warming. In this study, we explored the potential of clinometry as a technique to quantify glacier elevation changes. By analyzing shadow positions in monoscopic optical images, we were able to measure a glacier thinning rate of -1.9 +/- 1.7 ma(-1) between 2017 and 2021 for the Aletsch Glacier (Switzerland), consistent with previous observations.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Aldo Bertone, Roberto Seppi, Mattia Callegari, Giovanni Cuozzo, Niccolo Dematteis, Karl Krainer, Carlo Marin, Claudia Notarnicola, Francesco Zucca
Summary: The kinematic acceleration of rock glaciers observed in recent decades is related to climate change. While velocity variations on yearly to seasonal time scales are frequently investigated, velocity changes measured on shorter time scales (i.e., on hourly resolutions) are as yet poorly understood. In this study, we used ground-based synthetic aperture radar to investigate the displacement of a rock glacier on an hourly time scale in the European Alps. Our observations revealed a regular hourly velocity rhythm characterized by short phases of sharp acceleration (up to 0.9 mm/hr) lasting 4-11 hr followed by long phases of stagnation lasting 13-20 hr. This unprecedented observation opens up new perspectives in the analysis and interpretation of rock glacier kinematics.
GEOPHYSICAL RESEARCH LETTERS
(2023)
