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Comparing Discrete and Empirical Troposphere Delay Models: A Global IGS‐Based Evaluation

  •  15 June 2024

Key Points

  • The discrete and empirical troposphere delay models of the VMF data server is comprehensibly evaluated using the global International GNSS Service (IGS) data

  • The Site-wise of discrete model exhibits the best accuracy and is recommended first, followed by the Grid-wide and the empirical model

  • Each model shows different influences by the latitude, elevation, seasons and epochs

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Cold Electron Temperature in the Inner Magnetosphere Estimated Through the Dispersion Relation of ECH Waves From the Arase Satellite Observations

  •  11 June 2024

Key Points

  • Phase velocities of electron cyclotron harmonic (ECH) waves were calculated using interferometry observations from the Arase satellite

  • The low-energy electron temperature was estimated based on the dispersion relation of the ECH wave

  • It is found that low-energy electrons of the order of 1 eV account for the majority of the electron density distribution

Structures and Backscattering Characteristics of CUSAT 205 MHz Stratosphere‐Troposphere Radar at Cochin (10.04°N, 76.3°E)—First Results

  •  8 June 2024

Key Points

  • First observations of aspect-sensitivity characteristics at 205 MHz stratosphere–troposphere radar

  • Mechanisms for the formation of isotropic and anisotropic turbulence

  • Modulation of aspect sensitivity by wind shear and atmospheric stability

Open access

Radio Frequency Sensor: Very High Frequency Radio Frequency Lightning Detection in Geostationary Orbit

  •  4 June 2024

Key Points

  • The Radio Frequency Sensor (RFS) provides new RF lightning measurements from geosynchronous orbit

  • RFS primarily detects trans-ionospheric pulse pairs (TIPPs), and a much smaller fraction of cloud-to-ground lightning discharges

  • TIPP-derived altitudes allow tracking the altitude evolution of the convective region of a storm over time

A Method for Elevated Ducts Refinement Based on Convolutional Neural Network

  •  3 June 2024

Key Points

  • We propose the elevated duct height refinement model Dense-Linear convolutional neural network (DLCNN), which can capture the high frequency detail and locate high-frequency region

  • This research demonstrated that the prediction of electromagnetic wave propagation path loss benefits from elevated duct-height-based data refinement through DLCNN

  • The study avoided unreliable results by refining the top and bottom of the elevated duct's trapped layer successively

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Issue Information

  •  30 May 2024

AI‐Assisted Design of Printed Edge‐Fed Non‐Uniform Zig‐Zag Antenna for mm‐Wave Automotive Radar

  •  30 May 2024

Key Points

  • The non-uniform zig-zag antenna (NZA) PCB-based layout enables an effective control of antenna performance for fulfilling a set of conflicting project requirements within automotive radar framework

  • The proposed SbD-based optimization method is an effective and efficient tool for addressing the computational complexity of the design problem at hand

  • The realization and the measurement of a prototype prove also experimentally the suitability of the NZA layout for mm-wave radar applications

Design and Characterization of the Engineering Model of the Spectrometer Onboard LuSEE‐Night

  •  25 May 2024

Key Points

  • The engineering model of the spectrometer developed for the LuSEE-Night mission meets all mission requirements

  • Three mitigation techniques have been successfully implemented to suppress electromagnetic interference

  • The flight model is currently being developed and will be delivered to the integration site in early 2024

Open access

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

  •  20 May 2024

Key Points

  • The lateral deflection of high frequency radio waves caused by the solar terminator is investigated with ray tracing simulations

  • North-south propagation paths can experience significant (>20°) deflections in the morning and evening

  • East-west paths can also see significant deflections at high latitudes, at times when the solar terminator is also oriented east-west

Application of Wide‐Beam Transmission for Advanced Operations of SuperDARN Borealis Radars in Monostatic and Multistatic Modes

  •  17 May 2024

Key Points

  • We developed wide-beam transmission to probe an entire Super Dual Auroral Radar Network (SuperDARN) field of view simultaneously and to enable bistatic operations

  • New multistatic operation of SuperDARN radars provides additional measured velocity vector components

  • New wide-beam and multistatic operations significantly improve temporal resolution and spatial coverage by SuperDARN

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Statistics of total electron content depletions observed over the South American continent for the year 2008

Key Points

  • First time regional plots of TEC depletions
  • New numerical algorithm developed to automatically detect TEC depletions
  • Day-to-day variability of TEC depletions in a regional basis

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Consistency Evaluation of Precipitable Water Vapor Derived From ERA5, ERA‐Interim, GNSS, and Radiosondes Over China

Key Points

  • Consistency of precipitable water vapors (PWVs) derived from ERA5, ERA-Interim, GNSS, and radiosondes over China is evaluated
  • ERA5-derived PWV is indicated to have a higher accuracy than that acquired from its previous-generation product of the ERA-Interim
  • PWV geographical distribution derived from ERA5 and GNSS is quite consistent

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Large ionospheric disturbances produced by the HAARP HF facility

Key Points

  • HAARP facility produces unique results
  • Artificial plasma clouds are emission and optical signatures
  • Future HAARP experiments are needed to explain physics

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Accurate measurements of the dielectric constant of seawater at L band

Key Points

  • Dielectric measurements of seawater are made with a microwave cavity at 1.413 GHz
  • Measurements are made as a function of temperature and salinity for values found in open ocean
  • Accuracy is better than 0.3 for both real and imaginary parts of the dielectric constant

Open access

Breast Cancer Detection Based on Simplified Deep Learning Technique With Histopathological Image Using BreaKHis Database

Key Points

  • The results of an investigation to determine effectiveness of deep learning (DL)-based systems for detecting breast cancer is presented

  • The strategy here for DL training uses various image processing techniques for extracting different feature patterns

  • It is shown that the convolutional neural network models provide different results for different degrees of image resolution

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Fresnel Reflection and Transmission Coefficients for Temporally Dispersive Attenuative Media

Key Points

  • General expressions for Fresnel reflection and transmission coefficients for homogeneous and inhomogeneous plane waves are derived for TE- and TM polarized plane waves in complex media with loss
  • The critical angle for total internal reflection remains unchanged when material loss is included; the polarizing angle (for a TM polarized plane wave is changed otherwise, a pseudo Brewster's angle occurs at which the magnitude of the TM) polarization reflection coefficient is a minimum
  • Total reflection at grazing incidence on the optically denser medium does not occur when both media exhibit loss; total reflection does not occur at critical incidence when both media exhibit loss.

Plain Language Summary

Amplitude reflection and transmission coefficients for a time-harmonic electromagnetic plane wave incident upon a plane interface separating two different lossy media are developed.

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Calculating the absorption of HF radio waves in the ionosphere

Key Points

  • Either the Appleton-Hartree or Sen Wyller dispersion relation can be used to calculate absorption
  • It is necessary to utilize the correct collision frequency specification for each dispersion relation
  • Geophysical variations of collision frequency should be included in absorption calculations

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A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 1: DGSs and Parasitic Structures

Key Points

  • Multiple-Input-Multiple-Output (MIMO) patch antenna is required for high data rate transmission without additional bandwidth requirement

  • Mutual coupling reduction among antenna elements is a significant challenge while designing a compact antenna array system

  • Defected Ground Structures and Parasitics elements/structures for mutual coupling reduction have been discussed thoroughly in this article

Plain Language Summary

A comprehensive two-part review article with more than 330 references is proposed.

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An Indoor Path Loss Prediction Model Using Wall Correction Factors for Wireless Local Area Network and 5G Indoor Networks

Key Points

  • A modified effective wall loss model (EWLM) for indoor environment is presented
  • Real-time measurements and simulations for various indoor path loss models are used
  • Several frequency spectrum band were considered for evaluation purposes

Open access

First Observations With a GNSS Antenna to Radio Telescope Interferometer

Key Points

  • We developed technology to use a modified commercial Global Navigation Satellite Systems antenna as an element of a radio interferometer

  • We observed a strong interferometric response for Global Positioning System and Galileo satellites as well as celestial radio sources

  • We developed a technique that uses a clock solution to extend the coherent accumulation time with a rubidium clock to over 20 min

Plain Language Summary

We have developed a unique version of a device called a radio interferometer. This device usually uses two large radio telescopes to record data about the Earth or astronomical sources. Our device uses a Global Navigation Satellite Systems (GNSS) antenna and a Very Long Baseline Interferometry radio telescope instead of two radio telescopes. We hope to use it to link the two measurement systems. We tested it by using it to record signals from satellites and other astronomical objects. We found that it worked well and could detect signals from much further away than a GNSS antenna can detect alone. We also developed a new technique that allows us to continuously integrate signals for longer periods with a less precise clock without losing signal strength. This is the first time anyone has used a GNSS antenna with a radio telescope in this way.

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