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Cross-Polarization Gain Calibration of Linearly Polarized VLBI Antennas by Observations of 4C 39.25 Radio Sci. (IF 1.6) Pub Date : 2024-03-28 F. Jaron, I. Martí-Vidal, M. Schartner, J. González-García, E. Albentosa-Ruiz, S. Bernhart, J. Böhm, J. Gruber, S. Modiri, A. Nothnagel, V. Pérez-Díez, T. Savolainen, B. Soja, E. Varenius, M. H. Xu
Radio telescopes with dual linearly polarized feeds regularly participate in Very Long Baseline Interferometry. One example is the VLBI Global Observing System (VGOS), which is employed for high-precision geodesy and astrometry. In order to achieve the maximum signal-to-noise ratio, the visibilities of all four polarization products are combined to Stokes I before fringe-fitting. Our aim is to improve
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2024-03-27
No abstract is available for this article.
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A Cryogenic Wideband (2.5–14 GHz) Receiver System for the Arecibo Observatory 12 m Telescope Radio Sci. (IF 1.6) Pub Date : 2024-03-23 D. Anish Roshi, Phil Perillat, Felix Fernandez, Hamdi Mani, Benetge Perera, Periasamy K. Manoharan, Luis Quintero, Arun Venkataraman
In this paper we present details of the construction of a wideband, cryogenic receiver and its successful commissioning on the Arecibo Observatory 12 m telescope. The cryogenic receiver works in the 2.5–14 GHz frequency range. We upgraded the current narrow band, room temperature receivers of the telescope with the new wideband receiver. The current receiver is built around a Quadruple-Ridged Flared
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Variation in the Reflection Height of VLF/LF Transmitter Signals in the D-Region Ionosphere and the Possible Source: A 2018 Meteoroid in Hokkaido, Japan Radio Sci. (IF 1.6) Pub Date : 2024-02-26 H. Ohya, T. Suzuki, F. Tsuchiya, H. Nakata, K. Shiokawa
Several studies have examined ionospheric variation associated with meteorites, meteoroids, or meteors based on Global Satellite Navigation System total electron content observations. However, there have been few quantitative studies of the D-region of the ionosphere (60–90 km), which is associated with meteoroids. We investigated variation in the D-region during the passage of a meteoroid over northeastern
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2024-02-26
No abstract is available for this article.
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Measurement and Calibration of EMF: A Study Using Phone and GBDT for Mobile Communication Signals Radio Sci. (IF 1.6) Pub Date : 2024-02-19 Sheng Zeng, Weiwei Chen, Yuhang Ji, Liping Yan, Xiang Zhao
Electromagnetic exposure caused by mobile communication signals has always been a cause of concern. Due to the cost and inconvenience of professional measurement equipment, researchers have turned to smartphone APPs to study and assess the electric field strength caused by mobile communication signals. However, existing cell phone-based measurements have two weaknesses. First, no system architecture
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Processing of VLF Amplitude Measurements: Deduction of a Quiet Time Seasonal Variation Radio Sci. (IF 1.6) Pub Date : 2024-02-10 H. Schneider, V. Wendt, D. Banys, M. Clilverd, T. Raita
The amplitude of Very Low Frequency (VLF) transmissions propagating from transmitter to receiver between the Earth's surface and the ionospheric D-region is a useful measurement to detect changes in the ionization within the D-region ranging from 60 to 90 km. The VLF signal amplitude is disturbed by geomagnetic, solar, and atmospheric phenomena. To be able to identify perturbations in the VLF signal
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Electron Density Specification in the Inner Magnetosphere From the Narrow Band Receiver Onboard DSX Radio Sci. (IF 1.6) Pub Date : 2024-02-06 Yi-Jiun Su, John A. Carilli, J. Brent Parham, Xiangning Chu, Ivan A. Galkin, Gregory P. Ginet
Electron density plays an important role in the study of wave propagation and is known to be associated with the index of refraction and radiation belt diffusion coefficients. The primary objective of our investigation is to explore the possibility of implementing an onboard signal processing algorithm to automatically obtain electron densities from the upper hybrid resonance traces of wave spectrograms
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Calibration of an SKA-Low Prototype Station Using Holographic Techniques Radio Sci. (IF 1.6) Pub Date : 2024-01-02 Jishnu N. Thekkeppattu, Randall B. Wayth, Marcin Sokołowski
Performance of digitally beamformed phased arrays relies on accurate calibration of the array by obtaining gains of each antenna in the array. The stations of the Square Kilometer Array-Low (SKA-Low) are such digital arrays, where the station calibration is currently performed using conventional interferometric techniques. An alternative calibration technique similar to holography of dish based telescopes
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Characterizing Plasma Peak Density Thickness in the Ionosphere: A Single-Site Multi-Instrument Study Radio Sci. (IF 1.6) Pub Date : 2024-01-02 Mohamed O. Shammat, Bodo W. Reinisch, Ivan Galkin, Philip J. Erickson, Jay A. Weitzen, William C. Rideout
This paper introduces the Peak Density Thickness (PDT) formalism, a novel approach to representing the F2 layer's vertical electron density profile in the ionosphere. It diverges from the conventional “pointed-peak” model by suggesting a “broad-peak” or “flat-nose” profile where plasma density remains constant within an altitude interval χ. This theory is backed by independent observations, including
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An Improved 3D Numerical Ray-Tracing Method for Solving the Spitze Effects Based on Poeverlein's Diagram Radio Sci. (IF 1.6) Pub Date : 2024-01-03 Huan Song, Haiyin Qing, Jiyao Xu
The Spitze phenomenon is closely related to the Earth's magnetic field, and characterizes high-frequency (HF) rays propagating in the ionosphere. Specifically, when the reflection conditions are satisfied, HF rays are reflected perpendicular to the Earth's magnetic field. Studying the HF rays reflected from the Spitze region is important to indirectly learn about the ionosphere magnetic properties
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-12-28
No abstract is available for this article.
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Neuro-Adaptive Finite Time Composite Fault Tolerant Control for Attitude Control Systems of Satellites Radio Sci. (IF 1.6) Pub Date : 2023-12-29 Yingdong Wang, Tiantian Liang, Jianxiong Yang, Jian Liu
An adaptive finite time composite fault tolerant control strategy based on an optimized neural network for Attitude control systems (ACSs) of satellites is proposed considering the state time-varying delays, concurrent actuator and sensor faults, system uncertainties, modelable external disturbance and operating noise. An uncertain time-varying state space model for ACSs of satellites is established
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Consistency of the Troposphere Wet Delay From Water Vapor Radiometer and Co-Located GPS Station Radio Sci. (IF 1.6) Pub Date : 2023-12-18 Jun Jiang, Shuli Song, Weili Zhou, Qinghui Liu, Houcai Chen, Yongchen Jiang, Tianyu Zhou, Tarig A. Ali, Wei Li
The tropospheric delay acquired by the Global Navigation Position System (GPS) Precise Point Positioning (PPP) is continuous and steady, less affected by rainfall. The Water Vapor Radiometer (WVR) can provide real-time meteorological parameters but is more sensitive to high-frequency information in troposphere. To explore the use of WVR-retrieved tropospheric delay and assist other geodetic techniques
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The Ionospheric Exploration Based on TJU#01 Meteorological Microsatellite Mission: Initial Results Radio Sci. (IF 1.6) Pub Date : 2023-12-18 M. J. Wu, P. Guo, F. H. Li, N. F. Fu, X. Ma, Y. Cheng
The global navigation satellite system radio occultation technique is achieving increasing significance and extensive promotion in the remote sensing of near-earth atmosphere, climate, and ionosphere in recent three decades. Nowadays, many communities become interested in developing commercial mode in occultation measurement by launching massive nano- or cube satellite constellations at low costs.
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Analysis of Two Selected Solar Events in 2011 and 2015 With Mars Express Radio Occultation Data Radio Sci. (IF 1.6) Pub Date : 2023-12-14 Ananya Krishnan, Ozgur Karatekin, Sebastien Verkercke, Gregoire Henry, Beatriz Sánchez-Cano, Olivier Witasse
The temporal behavior of the Martian ionosphere is highly variable due to various dynamic processes including space weather events. Here, we study the effect of solar flares and coronal mass ejections (CMEs) on the Martian ionosphere for two selected solar events in 2011 and 2015, using the publicly available Mars EXpress (MEX) radio occultation (RO) data (MaRS). We developed a data processing software
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2–Bit Programmable Metasurface for Low Radar Cross Section Antenna and Beam Steering Applications Radio Sci. (IF 1.6) Pub Date : 2023-12-13 Muhammad Saleem, Muhammad Irfan, Mubarak A. Alanazi, Shahid Atiq
In this paper, a 2-bit water-based programmable digital metasurface for beam steering and backscatter field reduction applications is presented, a reflective and transmissive type water based programmable metasurface (WPMS) for RCS reduction and the antenna's beam steering is suggested, respectively. It has been demonstrated that a 2-bit water-based programmable unit cell can reduce RCS by changing
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Synthetic Aperture Radar Imaging Below a Random Rough Surface Radio Sci. (IF 1.6) Pub Date : 2023-12-11 Arnold D. Kim, Chrysoula Tsogka
Motivated by applications in unmanned aerial based ground penetrating radar for detecting buried landmines, we consider the problem of imaging small point like scatterers situated in a lossy medium below a random rough surface. Both the random rough surface and the absorption in the lossy medium significantly impede the target detection and imaging process. Using principal component analysis we effectively
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-12-07
No abstract is available for this article.
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Breast Cancer Detection Based on Simplified Deep Learning Technique With Histopathological Image Using BreaKHis Database Radio Sci. (IF 1.6) Pub Date : 2023-11-21 Tania Afroz Toma, Shivazi Biswas, Md Sipon Miah, Mohammad Alibakhshikenari, Bal S. Virdee, Sandra Fernando, Md Habibur Rahman, Syed Mansoor Ali, Farhad Arpanaei, Mohammad Amzad Hossain, Md Mahbubur Rahman, Ming-bo Niu, Naser Ojaroudi Parchin, Patrizia Livreri
Presented here are the results of an investigation conducted to determine the effectiveness of deep learning (DL)-based systems utilizing the power of transfer learning for detecting breast cancer in histopathological images. It is shown that DL models that are not specifically developed for breast cancer detection can be trained using transfer learning to effectively detect breast cancer in histopathological
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Iterative Gradient Correction (IGC) Method for True Height Analysis of Ionograms Radio Sci. (IF 1.6) Pub Date : 2023-11-06 M. Ankita, S. Tulasi Ram
Inversion of precise true height electron density profile from the measured virtual heights by the Ionosonde is a quite challenging and ill-posed problem. In this paper, we present a new method to compute the true height profiles from ionograms that relies on computing the propagation path of radio waves with time. This method does not use predefined polynomial functions to fit the vertical electron
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-10-26
No abstract is available for this article.
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Effect of Urbanization Through Land Coverage Classification Radio Sci. (IF 1.6) Pub Date : 2023-10-27 S. K. B. Sangeetha, Virendra Singh Kushwah, K. Sumangali, R. Sangeetha, Kiruba Thangam Raja, Sandeep Kumar Mathivanan
Land cover changes from rural or natural habitats to impervious surfaces that support various human activities are called urbanization. The evaluation of policy alternatives for future expansion and the promotion of sustainable urban development therefore place great emphasis on the mapping, analysis, and monitoring of land cover changes in metropolitan environments. By assessing changes in relevant
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Analysis and Application of the Electromagnetic Wave Propagation, Fields, and Dispersion Relation in an Elliptical Chiro Plasma Waveguide Immersed in Magnetized Plasma Radio Sci. (IF 1.6) Pub Date : 2023-10-26 N. Gholamshahi, A. Abdoli-Arani
This research proposes and investigates an elliptical waveguide filled with chiro plasma as its core and magnetized plasma as its clad region. The clad region is in the constant infinite magnetic field, and its direction is the same as the wave propagation in the chiro plasma elliptical waveguide. The electromagnetic wave propagation in the considered waveguide is studied. The expressions for electromagnetic
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High Performance Antenna System in MIMO Configuration for 5G Wireless Communications Over Sub-6 GHz Spectrum Radio Sci. (IF 1.6) Pub Date : 2023-10-17 Iftikhar ud Din, Mohammad Alibakhshikenari, Bal S. Virdee, Sadiq Ullah, Shakir Ullah, Muhammad Rizwan Akram, Syed Mansoor Ali, Patrizia Livreri, Ernesto Limiti
This paper presents a high-performance multiple input and multiple output (MIMO) antenna comprising 2 × 2 configuration of radiating elements that is designed for sub-6 GHz applications. The proposed MIMO antenna employs four identical radiating elements. High isolation between the radiating elements and therefore reduced mutual coupling is achieved by spatially arranging the radiating elements in
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Proposal of Technique for Analysis of Complementary Frequency Selective Surfaces Radio Sci. (IF 1.6) Pub Date : 2023-10-19 B. S. da Silva, A. L. P. S. Campos, M. E. T. Sousa, M. W. B. Silva, H. D. Andrade
A specific class of frequency selective surface (FSS) is the complementary frequency selective surface (CFSS) that has interesting characteristics such as high angular stability, multiple transmission and/or reflection bands, and the possibility of miniaturization. The analysis and design of this sort of structure are commonly performed using commercial software, which demands a high computational
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-09-30
No abstract is available for this article.
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Effects of the Relative Dynamics of Ionospheric Irregularities and GPS Satellites on Receiver Tracking Loop Performance Radio Sci. (IF 1.6) Pub Date : 2023-09-22 Trisani Biswas, Ashik Paul
Transionospheric satellite signals are exposed to perturbation, caused by irregularities generated in the ionosphere. However, the characteristics of the satellite motion can have an additional impact on signal perturbation, in addition to the effects of irregularity structures, that drift from west to east during geomagnetic quiet conditions. This paper reports the effect of Global Positioning System
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Quantitative Relationship Between Current Pulses and Associated Low-Frequency Magnetic Fields During Initial Stage of Rocket-Triggered Lightning Radio Sci. (IF 1.6) Pub Date : 2023-09-20 Xiao Li, Gaopeng Lu, Ziyi Wang, Rubin Jiang, Yanfeng Fan, Yucheng Zi, Feifan Liu, Kainat Qamar, Alice Nambalirwa, Tao Shi, Baoyou Zhu
The quantitative relationship between the channel-base current and the associated low-frequency magnetic field (B-field) during the early stage of rocket-triggered lightning was examined based on field experiments and numerical simulation. There is a good correlation between the current pulse and the corresponding B-field pulse in terms of amplitude and duration. In specific, the duration of current
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Aperture Synthesis Imaging of Ionospheric Irregularities Using Time Diversity MIMO Radar Radio Sci. (IF 1.6) Pub Date : 2023-09-20 D. L. Hysell, J. L. Chau
Aperture-synthesis images of ionospheric irregularities in the equatorial electrojet are computed using multiple-input multiple-output (MIMO) radar methods at the Jicamarca Radio Observatory. MIMO methods increase the number of distinct interferometry baselines available for imaging (by a factor of essentially three in these experiments) as well as the overall size of the synthetic aperture. The particular
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Printed Dual-Frequency Directional Antenna Loaded With Dual-Parasitic Strip Radio Sci. (IF 1.6) Pub Date : 2023-09-12 Chainarong Kittiyanpunya, Pongsathorn Chomdee
In this paper, the directional antenna is developed to construct the printed dual-frequency directional antenna for a 1-GHz/2.3-GHz dual-frequency sensor application. An auxiliary dipole element generating the higher resonant mode is set on a primary dipole element introducing the lower resonant mode. The feed balance is also designed to cover the desired frequency between two resonance frequencies
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Reconfigurable Antennas and Their Practical Applications—A Review Radio Sci. (IF 1.6) Pub Date : 2023-09-11 Sangeetha Subbaraj, Shweta B. Thomas
This paper presents the review on the design of various reconfigurable antennas and their applications in the current scenario. There are more challenges involved in the design of these antennas. This paper also describes the various methods used for reconfiguring the frequency bands. The single parameter reconfiguration and hybrid reconfiguration examples are analyzed with their performances. The
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Propagation Analysis Method Considering Angular Spread for Random Electromagnetic Waves in Magnetized Cold Plasma Radio Sci. (IF 1.6) Pub Date : 2023-09-04 Mamoru Ota, Yuji Tanaka, Yoshiya Kasahara
Random waves can be described as the sum of numerous plane waves, and stochastic processes describe their properties. Various methods have been used to widely investigate the propagation characteristics of electromagnetic waves in magnetized cold plasma based on a single-plane wave approximation. On the other hand, the properties of random waves are difficult to analyze using these methods. Instead
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Radio Occultation Data Analysis With Analytical Ray-Tracing Radio Sci. (IF 1.6) Pub Date : 2023-09-01 A. Caruso, A. Bourgoin, A. Togni, M. Zannoni, P. Tortora
Radio occultation experiments are a sensing technique dedicated to the remote sounding of planetary atmospheres. The technique exploits the frequency shift of a radio signal due to refraction in a planetary atmosphere. The aim is to infer the physical properties of the neutral atmosphere (e.g., pressure and temperature) and ionosphere (e.g., the electron number density). For one-way occultations, the
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-08-30
No abstract is available for this article.
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Structural Analysis of Nano Core PCF With Fused Cladding for Supercontinuum Generation in 6G Networks Radio Sci. (IF 1.6) Pub Date : 2023-08-29 Rajesh Anbazhagan, S. Chandru, Ravikumar Chinthaginjala, Kalapraveen Bagadi, Mohammad Alibakhshikenari, Bal S. Virdee, Syed Mansoor Ali, Iyad Dayoub, Patrizia Livreri, Sonia Aïssa
The Sixth Generation (6G) networks have identified the use of frequency range between 95 GHz and 3 THz with a targeted data rate of 1 Terabytes/second at the access network for holographic video applications. As is demands broadening of spectrum at the core network, this paper proposes a Supercontinuum Generation (SCG) through photonic crystal fiber (PCF) as it provides excellent broadening of the
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An Entropy Weight-Based Method for Path Loss Predictions for Terrestrial Services in the VHF and UHF Bands Radio Sci. (IF 1.6) Pub Date : 2023-08-25 Jian Wang, Yulong Hao, Cheng Yang
VHF and UHF are widely used frequency bands, and accurate path loss prediction in these bands is of great significance. In order to improve the prediction accuracy and stability of radio wave propagation, we propose a combined modeling method based on the entropy weight method. This method assigns appropriate weights to the predicted values of sub-models using entropy, and calculates the final predicted
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Four-Beams-Reconfigurable Circular-Ring Array Antennas for Monopulse Radar Applications Radio Sci. (IF 1.6) Pub Date : 2023-08-22 Giada M. Battaglia, Tommaso Isernia, Roberta Palmeri, Andrea F. Morabito
We propose a new approach to the mask-constrained power synthesis of reconfigurable circular-ring array antennas for monopulse radar applications. By resorting to Orbital Angular Momentum vortex beams, and without increasing either the complexity of the beam forming network or the signal processing times with respect to the state-of-art solutions, the proposed method allows improving the precision
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Suppresion of Log-Periodic Dipole Antenna Spurious Radiation by Lumped Element Loading for Radioastronomical Application Radio Sci. (IF 1.6) Pub Date : 2023-08-21 Georgios Kyriakou, Pietro Bolli, Lorenzo Mezzadrelli
Log-Periodic Dipole Antennas have been known to provide good performance over large fractional bandwidths. However, optimized designs of log-periodic antennas, in particular for radioastronomy and remote sensing, need to tackle the spurious radiation of secondary dipole harmonics that can compromise the gain smoothness and therefore the ability to detect natural spectral features emitted by the probed
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A Sorting Method for Radar Echo Extraction Based on Observation Submatrix Radio Sci. (IF 1.6) Pub Date : 2023-08-16 Zhipeng Liu, Yanyang Gu, Baojie Hu, Fuhong Gong, Zhipeng Fan
With the advancement of active jamming technology, a variety of new types of coherent jamming based on digital radio frequency memory have been proposed and implemented in practice, posing serious threats to modern radar systems due to their flexibility, suppression, and deception characteristics. Hence the research on radar echo extraction is necessary and challenging. In this paper, we focus on removing
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First Observations With a GNSS Antenna to Radio Telescope Interferometer Radio Sci. (IF 1.6) Pub Date : 2023-08-14 J. Skeens, J. York, L. Petrov, D. Munton, K. Herrity, R. Ji-Cathriner, S. Bettadpur, T. Gaussiran
We describe the design of a radio interferometer composed of a Global Navigation Satellite Systems (GNSS) antenna and a Very Long Baseline Interferometry radio telescope. Our eventual goal is to use this interferometer for geodetic applications including local tie measurements. The GNSS element of the interferometer uses a unique software-defined receiving system and modified commercial geodetic-quality
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Detection of Ore-Forming Elements Migrated From Rock and Soil to Vegetation Leaves Using Hyperspectral Data Radio Sci. (IF 1.6) Pub Date : 2023-08-10 Zhou Chao, Fan Xianchuang, Wu Tong, Zhang Yuanzhi, Chen Shengbo
In this paper, we present the detection of ore-forming elements migrated from soil and rock to vegetation leaves using hyperspectral data. The rock, soil (C, B, and A layer), and vegetation (root, stem, and leaf) samples with the measurements of spectra and element concentrations in the vertical section of the abandoned pits were collected. The wavelet approach is applied to analyze the correlations
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Enhancement of Precise Underwater Object Localization Radio Sci. (IF 1.6) Pub Date : 2023-08-08 Sathish Kaveripakam, Ravikumar Chinthaginjala, Rajesh Anbazhagan, Mohammad Alibakhshikenari, Bal Virdee, Salahuddin Khan, Giovanni Pau, Chan Hwang See, Iyad Dayoub, Patrizia Livreri, Raed Abd-Alhameed
Underwater communication applications extensively use localization services for object identification. Because of their significant impact on ocean exploration and monitoring, underwater wireless sensor networks (UWSN) are becoming increasingly popular, and acoustic communications have largely overtaken radio frequency broadcasts as the dominant means of communication. The two localization methods
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Multiband Metasurface-Based Absorber for Applications in X, Ku, and K Bands Radio Sci. (IF 1.6) Pub Date : 2023-08-07 H. J. S. Coelho, B. Araújo, M. W. B. Silva, T. N. Ferreira, A. L. P. S. Campos, C. Junqueira, Erich Kemptner, Andrey Osipov
In this paper, a slotted-circle patch metasurface that can efficiently absorb electromagnetic (EM) waves in three different bands is proposed. Based on the fundamental resonance of a single circular patch, EM resonances are generated making slits in the circular patch leading to multi-band operation. Simulation results show that the proposed structure can absorb signals in three different bands, namely
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Compact Sub-Semicircular Axial Gradient Index Lens Synthesized by Metasurfaces: A Promising Solution for Miniaturized Antenna and Subwavelength Focusing Systems Radio Sci. (IF 1.6) Pub Date : 2023-08-07 Yuan-Chu Wang, Malcolm Ng Mou Kehn
We present the design, fabrication, and experimental measurements of an Axial Gradient-index (AGRIN) flat lens synthesized by 2D periodic metallic patches on a grounded dielectric slab, known as metasurfaces. Metasurfaces can be considered as artificial materials that possess unique characteristics, which mainly revolve around the two-dimensional distribution of the structure. By manipulating the phase
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-07-28
No abstract is available for this article.
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Scale-Separated Dynamic Mode Decomposition and Ionospheric Forecasting Radio Sci. (IF 1.6) Pub Date : 2023-07-26 Daniel J. Alford-Lago, Christopher W. Curtis, Alexander T. Ihler, Katherine A. Zawdie
We present a method for forecasting the foF2 and hmF2 parameters using modal decompositions from measured ionospheric electron density profiles. Our method is based on Dynamic Mode Decomposition (DMD), which provides a means of determining spatiotemporal modes from measurements alone. Our proposed extensions to DMD use wavelet decompositions that provide separation of a wide range of high-intensity
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An ASC-Based Unitary Matrix Pencil Method for Parameter Estimation of Group Target Radio Sci. (IF 1.6) Pub Date : 2023-07-22 Xiyuan Sun, Pengfei Gu, Zi He, Hao Wen, Dazhi Ding, Shaoqing Guo, You Li
The unitary matrix pencil (UMP) method has been successfully applied to antenna array optimization. In this paper, the UMP method is applied to the parameter estimation of target detection based on the attributed scattering center (ASC) model. This method can accurately estimate the number of arbitrary group targets in the space. First, the RCS is reconstructed based on the ASC model. Since the unitary
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Statistical Study on Plasma Velocities in the Bottom-Side Ionosphere Over Low Latitude Hainan Station: Digisonde Measurement Radio Sci. (IF 1.6) Pub Date : 2023-07-11 Guojun Wang, Jiankui Shi, Klaus Torkar, Zheng Wang, Xiao Wang, Zhengwei Cheng, Sheping Shang
Data measured by the Digisonde at the low-latitude station Hainan from 2003 to 2016 are statistically analyzed to specify the diurnal average variations of the bottom-side F region ionospheric plasma velocity vector V. This is the first comprehensive analysis of Digisonde measurements of low latitude F region plasma velocities in the East Asian sector that use a database covering more than one solar
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Radio Instrument Package for Lunar Ionospheric Observation: A Concept Study Radio Sci. (IF 1.6) Pub Date : 2023-07-08 C. Watson, P. T. Jayachandran, A. Kashcheyev, D. R. Themens, R. B. Langley, R. Marchand, A. W. Yau
The lunar ionosphere is a ∼100 km thick layer of electrically charged plasma surrounding the moon. Despite knowledge of its existence for decades, the structure and dynamics of the lunar plasma remain a mystery due to lack of consistent observational capacity. An enhanced observational picture of the lunar ionosphere and improved understanding of its formation/loss mechanisms is critical for understanding
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Statistical Characteristics of Mid-Latitude Ionospheric F-Region Backscatter Observed by the SuperDARN Jiamusi Radar Radio Sci. (IF 1.6) Pub Date : 2023-07-06 Wei Wang, Jiaojiao Zhang, Chi Wang, Junjie Chen, Tong Dang, Jiuhou Lei, John Michael Ruohoniemi
The Jiamusi (JME) radar is the first high-frequency coherent scatter radar independently developed in China. In this study, we investigate the statistical characteristics of the Jiamusi radar scattering occurrence rate from the F-region ionosphere between 40°N and 65°N geomagnetic latitude (MLAT) from March 2018 to November 2019. Then, the diurnal and seasonal variations in scattering echoes and their
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A Novel Low-Loss Planar PRGW Crossover Design for 5G Applications Radio Sci. (IF 1.6) Pub Date : 2023-07-05 Zahra Mousavirazi, Mohamed Mamdouh M. Ali, Pejman Rezaei, Abdel R. Sebak, Tayeb A. Denidni
In this paper, a planar 0-dB crossover using printed ridge gap waveguide (PRGW) technology is proposed and designed for millimeter-wave applications. PRGW as a quasi-TE mode is considered as the modern guiding technology at high frequencies and for the 5G and other upcoming communications. A prototype of the proposed PRGW crossover working around 30 GHz is fabricated and measured to validate the simulated
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A Survey of Five Generations of MIMO Multiband Base Station Antennas Radio Sci. (IF 1.6) Pub Date : 2023-07-05 Hafiz Usman Tahseen, Luciano Mescia, Luca Catarinucci
As telecommunication systems evolve, there is an increasing demand for multi-band MIMO base-station antennas. Antenna arrays are generally used to support multiple frequencies with multiple ports in a compact size. However, this can result in significant degradation in scattering patterns and return loss/port isolation due to the close proximity of the radiation from the array. Various techniques have
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Issue Information Radio Sci. (IF 1.6) Pub Date : 2023-06-30
No abstract is available for this article.
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Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S4) Radio Sci. (IF 1.6) Pub Date : 2023-06-25 Andrew K. Sun, Xiaoqing Pi, Charles Rino, Jiyun Lee
The intensity scintillation index (S4) exhibits a linear frequency dependence derived from a power law phase screen model, with the exponent determined by the phase spectral index (p). However, it is well known that a departure from linearity occurs as S4 increases and saturates under strong scatter conditions. Additionally, statistical errors over a finite time window can also cause the scintillation
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Comparative Assessment of the Performances of GPS-TEC Assisted NTCM, NeQuick2 and Neural Network Models to Describe the East-African Equatorial Ionosphere Radio Sci. (IF 1.6) Pub Date : 2023-06-23 B. Getahun Gelaw, M. Nigussie, A. Tebabal
Different ionospheric climatological models such as NeQuick2 and NTCM have been developed to mitigate the ionosphere impact on the trans-ionosphere propagating radio wave. Moreover, the Neural Network (NN) is used to model and characterize the ionosphere. However, no one has compared the performances of NeQuick2, NTCM, and NN after adapting to GPS TEC. This study evaluates their performances in the
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SAR Imaging Based on OAM-ωK Algorithm Radio Sci. (IF 1.6) Pub Date : 2023-06-19 Han Yueyue, Li Chenlu, Du Yongxing, Qin Ling, Li Baoshan, Chen Linlin, Liu Zhengliang
Traditional radar imaging was restricted by the antenna aperture and imaging scene. It was difficult to improve azimuth resolution greatly. The vortex electromagnetic (EM) waves carrying orbital angular momentum have a special helical phase wavefront structure. The vortex EM waves could bring more degrees of freedom when applied to synthetic aperture radar imaging, make it possible for ultra-high resolution
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Precision of Spacecraft Doppler Tracking at Low Signal-To-Noise Ratios Radio Sci. (IF 1.6) Pub Date : 2023-06-13 D. R. Buccino, K. Oudrhiri, M. Parisi, R. S. Park, E. Mazarico, P. Tortora, P. Withers, A. Genova, M. Zannoni
The signal-to-noise ratio received at Earth is typically larger than 10 dB-Hz for radio tracking of a spacecraft in deep space, allowing a phase-locked loop to execute reliable carrier tracking. Recently, missions have been proposed to utilize low-gain antennas for Doppler tracking where the signal-to-noise ratio may be at the single-digit (dB-Hz) level. In this work, we discuss spacecraft Doppler
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The Phase Response of a Rough Rectangular Facet for Radar Sounder Simulations of Both Coherent and Incoherent Scattering Radio Sci. (IF 1.6) Pub Date : 2023-06-02 C. Gerekos, M. S. Haynes, D. M. Schroeder, D. D. Blankenship
With radar sounders, coherent backscattering simulations from global planetary digital elevation models (DEMs) typically display a deficit in diffuse clutter, which is mainly due to the implicit assumption that roughness at scales below the resolution of the DEM is absent. Indeed, while polynomial approximations of the phase evolution across the facet allow for fast and mathematically rigorous simulators
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Reconstructing Meteoroid Trajectories Using Forward Scatter Radio Observations From the BRAMS Network Radio Sci. (IF 1.6) Pub Date : 2023-06-01 Joachim Balis, Hervé Lamy, Michel Anciaux, Emmanuel Jehin
In this paper, we aim to reconstruct meteoroid trajectories using a forward scatter radio system transmitting a continuous wave (CW) with no modulation. To do so, we use the meteor echoes recorded at the receivers of the BRAMS (Belgian RAdio Meteor Stations) network. This system consists, at the time of writing, of a dedicated transmitter and 44 receiving stations located in and nearby Belgium, all