Drones are highly autonomous, remote-controlled platforms capable of performing a variety of tasks in diverse environments. A digital twin (DT) is a virtual replica of a physical system. The integration of DT with drones gives the opportunity to manipulate the drone during a mission. In this paper, the architecture of DT is presented in order to explain how the physical environment can be represented. The techniques via which drones are collecting the necessary information for DT are compared as a next step to introduce the main methods that have been applied in DT progress by drones. The findings of this research indicated that the process of incorporating DTs into drones will result in the advancement of readings from all sensors, control code and intelligence. This can be executed on the DTs, remote control for the performance of complex tasks in a variety of application environments, and simulation on the DTs without having an effect on the actual drone. On the other hand, in order to develop three-dimensional representations of structures and construction sites, a method known as photogrammetry is used to generate these models employing drones as aerial scanners. In spite of this, there are a number of technological and social-political obstacles that should be taken in consideration. These challenges include the interoperability of different sensors, the creation of efficiently optimized data processing algorithms, and concerns over data privacy and security.
{"title":"Integrating drones with digital twins for aerial remote sensing","authors":"Izzat Al-Darraji;Fazal Qudus Khan;Tania Tareq Salim;Georgios Tsaramirsis;Houssem Jerbi;Ayad A. Kakei;Ayad Ghany Ismaeel","doi":"10.1029/2023RS007700","DOIUrl":"https://doi.org/10.1029/2023RS007700","url":null,"abstract":"Drones are highly autonomous, remote-controlled platforms capable of performing a variety of tasks in diverse environments. A digital twin (DT) is a virtual replica of a physical system. The integration of DT with drones gives the opportunity to manipulate the drone during a mission. In this paper, the architecture of DT is presented in order to explain how the physical environment can be represented. The techniques via which drones are collecting the necessary information for DT are compared as a next step to introduce the main methods that have been applied in DT progress by drones. The findings of this research indicated that the process of incorporating DTs into drones will result in the advancement of readings from all sensors, control code and intelligence. This can be executed on the DTs, remote control for the performance of complex tasks in a variety of application environments, and simulation on the DTs without having an effect on the actual drone. On the other hand, in order to develop three-dimensional representations of structures and construction sites, a method known as photogrammetry is used to generate these models employing drones as aerial scanners. In spite of this, there are a number of technological and social-political obstacles that should be taken in consideration. These challenges include the interoperability of different sensors, the creation of efficiently optimized data processing algorithms, and concerns over data privacy and security.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-11"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrew M. Pepper;Victoriya V. Forsythe;Sarah E. McDonald;Katherine A. Zawdie
ANCHOR is a novel data assimilation model developed at the U.S. Naval Research Laboratory for nowcasting ionospheric parameters relevant to space weather applications. ANCHOR incorporates electron density observations from ionosondes, Abel inverted radio occultation (RO) data, and ground-based GNSS receiver data into a PyIRI-driven model background using the Kalman filter technique. The purpose of this study is to validate the estimated model parameters with parameters derived from electron density observations from incoherent scatter radars (ISR) at various levels of solar activity. Four distinct events were identified from a 6-year data set spanning from 2018 to 2024 collected from four operating ISRs located at varying latitudes west of the prime meridian: Arecibo, Jicamarca, Millstone Hill, and Poker Flat. These events span a range of solar activity levels, with two events at low solar activity, one at moderate and one at high solar activity, each with data coverage from at least two radars. Parameter extraction is achieved by fitting Epstein functions to the electron density profiles, where the peak density (NmF2), peak altitude (hmF2), and the bottomside and topside thickness parameters are simultaneously optimized to characterize the F2 layer. The ISR-extracted parameters are used to directly compare with the model outputs using the root mean square error (RMSE) analysis method. Up to 75% improvement relative to the background model for NmF2, hmF2, and thickness parameters with consistency across all latitudes is found. Additionally, the ANCHOR assimilative model was compared to PyIRTAM model, showing a good agreement between the performances of both systems.
{"title":"Validation of ANCHOR ionospheric data assimilation model using incoherent scatter radars","authors":"Andrew M. Pepper;Victoriya V. Forsythe;Sarah E. McDonald;Katherine A. Zawdie","doi":"10.1029/2024RS008125","DOIUrl":"https://doi.org/10.1029/2024RS008125","url":null,"abstract":"ANCHOR is a novel data assimilation model developed at the U.S. Naval Research Laboratory for nowcasting ionospheric parameters relevant to space weather applications. ANCHOR incorporates electron density observations from ionosondes, Abel inverted radio occultation (RO) data, and ground-based GNSS receiver data into a PyIRI-driven model background using the Kalman filter technique. The purpose of this study is to validate the estimated model parameters with parameters derived from electron density observations from incoherent scatter radars (ISR) at various levels of solar activity. Four distinct events were identified from a 6-year data set spanning from 2018 to 2024 collected from four operating ISRs located at varying latitudes west of the prime meridian: Arecibo, Jicamarca, Millstone Hill, and Poker Flat. These events span a range of solar activity levels, with two events at low solar activity, one at moderate and one at high solar activity, each with data coverage from at least two radars. Parameter extraction is achieved by fitting Epstein functions to the electron density profiles, where the peak density (NmF2), peak altitude (hmF2), and the bottomside and topside thickness parameters are simultaneously optimized to characterize the F2 layer. The ISR-extracted parameters are used to directly compare with the model outputs using the root mean square error (RMSE) analysis method. Up to 75% improvement relative to the background model for NmF2, hmF2, and thickness parameters with consistency across all latitudes is found. Additionally, the ANCHOR assimilative model was compared to PyIRTAM model, showing a good agreement between the performances of both systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-20"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joachim Balis;Hervé Lamy;Michel Anciaux;Emmanuel Jehin;Johan De Keyser;Daniel Kastinen;Peter G. Brown
This study presents an enhanced method for reconstructing meteoroid trajectories and speeds using the Belgian RAdio Meteor Stations forward scatter radio network. A novel extension of the pre-t0 phase technique, originally developed for backscatter radars, has been adapted for forward scatter continuous wave systems. This method leverages phase data recorded before the meteoroid reaches the specular reflection point t0 to improve speed estimations. Additionally, we combine this newly determined pre-t0 speed information with time of flight measurements into the trajectory solver to reduce uncertainties in meteoroid path and speed reconstructions. A Markov Chain Monte Carlo method is employed to propagate measurement uncertainties to the trajectory parameters. The reconstructed trajectories and speeds are validated against optical data from the CAMS-BeNeLux network. The results show significant improvements in the accuracy and robustness of speed and inclination determination.
{"title":"Enhanced meteoroid trajectory and speed reconstruction using a forward scatter radio network: Pre-t0 phase technique and uncertainty analysis","authors":"Joachim Balis;Hervé Lamy;Michel Anciaux;Emmanuel Jehin;Johan De Keyser;Daniel Kastinen;Peter G. Brown","doi":"10.1029/2025RS008305","DOIUrl":"https://doi.org/10.1029/2025RS008305","url":null,"abstract":"This study presents an enhanced method for reconstructing meteoroid trajectories and speeds using the Belgian RAdio Meteor Stations forward scatter radio network. A novel extension of the pre-t<inf>0</inf> phase technique, originally developed for backscatter radars, has been adapted for forward scatter continuous wave systems. This method leverages phase data recorded before the meteoroid reaches the specular reflection point t<inf>0</inf> to improve speed estimations. Additionally, we combine this newly determined pre-t<inf>0</inf> speed information with time of flight measurements into the trajectory solver to reduce uncertainties in meteoroid path and speed reconstructions. A Markov Chain Monte Carlo method is employed to propagate measurement uncertainties to the trajectory parameters. The reconstructed trajectories and speeds are validated against optical data from the CAMS-BeNeLux network. The results show significant improvements in the accuracy and robustness of speed and inclination determination.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-20"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Charles Rino;Charles Carrano;Dmytro Vasylyev;Theodore Beach;Brian Breitsch;Yu Morton;Keith Groves
Advanced global navigation satellite system receivers typically report intensity scintillation indices, phase scintillation indices, and rate of total electron content change indices (ROTI). Extensive regional measurements are being accumulated and made available as diagnostic resources. Although each parameter is derived independently from measured intensity and phase time series, to the extent that ionospheric structure is the source of the scintillation manifestations, more definitive scintillation diagnostics can be predicted for structure characterized by a two-component inverse power law spectral density function. This paper derives theoretical predictions of main statistical characteristics of signal amplitude and phase that has been randomly modulated while propagating through two-dimensional random phase screens. An irregularity parameter estimation procedure is developed that generates maximum likelihood parameter estimates. It is shown that the estimated parameters reconcile theoretical prediction with reasonable accuracy. Phase-screen simulations are used to verify the theoretical predictions. The scintillation model is embedded in a generic signal model with additive noise, which allows direct application to appropriately detrended intensity and phase measurements.
{"title":"On phase screen models for scintillation diagnostics","authors":"Charles Rino;Charles Carrano;Dmytro Vasylyev;Theodore Beach;Brian Breitsch;Yu Morton;Keith Groves","doi":"10.1029/2024RS008204","DOIUrl":"https://doi.org/10.1029/2024RS008204","url":null,"abstract":"Advanced global navigation satellite system receivers typically report intensity scintillation indices, phase scintillation indices, and rate of total electron content change indices (ROTI). Extensive regional measurements are being accumulated and made available as diagnostic resources. Although each parameter is derived independently from measured intensity and phase time series, to the extent that ionospheric structure is the source of the scintillation manifestations, more definitive scintillation diagnostics can be predicted for structure characterized by a two-component inverse power law spectral density function. This paper derives theoretical predictions of main statistical characteristics of signal amplitude and phase that has been randomly modulated while propagating through two-dimensional random phase screens. An irregularity parameter estimation procedure is developed that generates maximum likelihood parameter estimates. It is shown that the estimated parameters reconcile theoretical prediction with reasonable accuracy. Phase-screen simulations are used to verify the theoretical predictions. The scintillation model is embedded in a generic signal model with additive noise, which allows direct application to appropriately detrended intensity and phase measurements.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-17"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brent Page;Alain Lecacheux;Marc Pulupa;Stuart D. Bale
A space-borne radio-frequency antenna is typically located in the vicinity of a conductive spacecraft body that influences its beam. Also, at wavelengths that greatly exceed the sizes of such an antenna and spacecraft, the antenna is expected to have the beam of an equivalent short dipole. This type of beam varies with direction as sin2(ζ), where ζ is the polar angle relative to the antenna's electrical axis. We describe a Markov Chain Monte Carlo method for fitting for this axis and apply it to measurements from Parker Solar Probe's four whip antennas. Depending on how the antennas are connected to the spacecraft's radio receiver, their voltages are processed individually for “monopole” measurements or differenced for “dipole” measurements. We find with a reduced χ2 = 1.01 that the electrical axes of the dipoles deviate from the whip axes by 0° — 4°. A byproduct of this fit is a measurement of the l = 2 spherical harmonic expansion coefficients of the brightness distribution on the sky. We utilize this measurement to in turn determine the electrical axes of the monopoles from a much smaller data set. These are found to be deflected ≈ 27° away from the whips. Rheometric calibration and computational electromagnetic simulations of the antenna system corroborate the fits. All of the analyzed data were captured with the spacecraft solar array deployed, which perturbs the electrical axes of the antennas by a few degrees.
{"title":"Calibration of electrically short antennas using the l = 2 spherical harmonic expansion coefficients of the radio brightness distribution on the sky between 0.5 and 6.8 MHz","authors":"Brent Page;Alain Lecacheux;Marc Pulupa;Stuart D. Bale","doi":"10.1029/2024RS008137","DOIUrl":"https://doi.org/10.1029/2024RS008137","url":null,"abstract":"A space-borne radio-frequency antenna is typically located in the vicinity of a conductive spacecraft body that influences its beam. Also, at wavelengths that greatly exceed the sizes of such an antenna and spacecraft, the antenna is expected to have the beam of an equivalent short dipole. This type of beam varies with direction as sin<sup>2</sup>(ζ), where ζ is the polar angle relative to the antenna's electrical axis. We describe a Markov Chain Monte Carlo method for fitting for this axis and apply it to measurements from Parker Solar Probe's four whip antennas. Depending on how the antennas are connected to the spacecraft's radio receiver, their voltages are processed individually for “monopole” measurements or differenced for “dipole” measurements. We find with a reduced χ<sup>2</sup> = 1.01 that the electrical axes of the dipoles deviate from the whip axes by 0° — 4°. A byproduct of this fit is a measurement of the l = 2 spherical harmonic expansion coefficients of the brightness distribution on the sky. We utilize this measurement to in turn determine the electrical axes of the monopoles from a much smaller data set. These are found to be deflected ≈ 27° away from the whips. Rheometric calibration and computational electromagnetic simulations of the antenna system corroborate the fits. All of the analyzed data were captured with the spacecraft solar array deployed, which perturbs the electrical axes of the antennas by a few degrees.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-19"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The classical transmission line (TL) equations are constrained by the quasi-TEM (Transverse Electromagnetic) approximation. The Theory of Maxwellian Circuit (TMC) establishes a generalized TL equation. It employs full-wave analysis results to fit the distributed parameters of the TL equation, thereby determining a generalized TL equation form that is not limited to the quasi-TEM approximation. TMC can be regarded as a data-driven modeling approach. Furthermore, the TL equation formulated by TMC can serve as a reference for other generalized TL equations in terms of both equation form and parameters, including coefficient terms and inhomogeneous terms. This paper analyzes the distributed parameters and source terms in the differential equations of TMC and improves the form of the source terms, which implies corresponding changes in the values of the distributed parameter terms. Numerical simulations reveal that the improved TMC model offers improved accuracy in predicting current distribution along TLs. Furthermore, several technical details related to the numerical implementation of TMC are presented, including avoiding dealing directly with non-smooth positions in TLs, using a set of boundary conditions with weak ill-conditioning, and choosing the range of [λ/40, λ/20] as the length of segments based on computational accuracy and efficiency. These considerations represent novel contributions not previously mentioned. These studies will aid in applying machine learning to transmission line modeling and analysis and advance the development of generalized TL equations and theory.
{"title":"The improvement and implementation of theory of Maxwellian circuit","authors":"Yuhang Ji;Fan Rong;Liping Yan;Xiang Zhao","doi":"10.1029/2024RS008205","DOIUrl":"https://doi.org/10.1029/2024RS008205","url":null,"abstract":"The classical transmission line (TL) equations are constrained by the quasi-TEM (Transverse Electromagnetic) approximation. The Theory of Maxwellian Circuit (TMC) establishes a generalized TL equation. It employs full-wave analysis results to fit the distributed parameters of the TL equation, thereby determining a generalized TL equation form that is not limited to the quasi-TEM approximation. TMC can be regarded as a data-driven modeling approach. Furthermore, the TL equation formulated by TMC can serve as a reference for other generalized TL equations in terms of both equation form and parameters, including coefficient terms and inhomogeneous terms. This paper analyzes the distributed parameters and source terms in the differential equations of TMC and improves the form of the source terms, which implies corresponding changes in the values of the distributed parameter terms. Numerical simulations reveal that the improved TMC model offers improved accuracy in predicting current distribution along TLs. Furthermore, several technical details related to the numerical implementation of TMC are presented, including avoiding dealing directly with non-smooth positions in TLs, using a set of boundary conditions with weak ill-conditioning, and choosing the range of [λ/40, λ/20] as the length of segments based on computational accuracy and efficiency. These considerations represent novel contributions not previously mentioned. These studies will aid in applying machine learning to transmission line modeling and analysis and advance the development of generalized TL equations and theory.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a numerical ray-tracing model, AU-Ray, for simulating the HF/VHF radio wave propagation in the ionosphere. AU-Ray operates in fully three-dimensional magnetoionic conditions along similar principles as applied in some other widely used ray-tracing codes (e.g., PHaRLAP and Proplab-Pro). The AU-Ray software has been developed in C++ and built entirely on open-source packages, which makes it an efficient standalone alternative for other ray-tracing models. The model can handle customized user-defined sources for the ionospheric background conditions, in addition to the well-known empirical models. Use cases for AU-Ray include analyzing satellite and ground-based measurements, investigating ionospheric anomalies, and supporting real-time operations. Validation against other ray-tracing models demonstrates that AU-Ray provides consistent results with Proplab-Pro and PHaRLAP and has similar performance in computational efficiency as PHaRLAP, which is significantly higher than that of Proplab-Pro. As an additional feature when compared to PHaRLAP's capabilities AU-Ray's photon mapping tool allows operations to solve large quantities of rays for detailed propagation maps in experimental background conditions.
{"title":"AU-Ray program for modeling radio wave propagation in the ionosphere","authors":"E. A. O. Hirvonen;K. Kauristie;E. Kallio","doi":"10.1029/2024RS008209","DOIUrl":"https://doi.org/10.1029/2024RS008209","url":null,"abstract":"This paper presents a numerical ray-tracing model, AU-Ray, for simulating the HF/VHF radio wave propagation in the ionosphere. AU-Ray operates in fully three-dimensional magnetoionic conditions along similar principles as applied in some other widely used ray-tracing codes (e.g., PHaRLAP and Proplab-Pro). The AU-Ray software has been developed in C++ and built entirely on open-source packages, which makes it an efficient standalone alternative for other ray-tracing models. The model can handle customized user-defined sources for the ionospheric background conditions, in addition to the well-known empirical models. Use cases for AU-Ray include analyzing satellite and ground-based measurements, investigating ionospheric anomalies, and supporting real-time operations. Validation against other ray-tracing models demonstrates that AU-Ray provides consistent results with Proplab-Pro and PHaRLAP and has similar performance in computational efficiency as PHaRLAP, which is significantly higher than that of Proplab-Pro. As an additional feature when compared to PHaRLAP's capabilities AU-Ray's photon mapping tool allows operations to solve large quantities of rays for detailed propagation maps in experimental background conditions.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-14"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herein, we put forward an ultra-thin and highly efficient multifunctional wideband reflective polarization converter metasurface for the manipulation of polarization state of the electromagnetic wave. Strong anisotropic characteristics have been achieved by employing a diagonally kept double-sided modified arrow on single layer FR4 substrate backed with copper. Numerical studies show that on one hand, the realized metasurface is capable to convert a linearly polarized (LP) wave (y/x) into its orthogonal counterpart (x/y) over 6.35–9.00 GHz and 15.47–16.03 GHz exceeding 90% polarization conversion ratio. On the other hand, it efficiently transforms the LP wave into reflected circularly polarized (CP) wave over 5.32–6.15 GHz, 9.50–15.22 GHz, and 16.24–17.45 GHz with an axial ratio lower than 3 dB. It is investigated that the type of circular polarization is right-handed over first two above bands while showing left-handed in the last band. Due to the minimum level of tolerance in reflection phases (<22°) with respect to the acceptable limits, the proposed unit-cell exhibits exceptional CP and cross polarization characteristics in the given bands. An array of 33 × 33 unit-cells is created as a prototype and tested experimentally to confirm the suggested structure.
{"title":"A broadband metasurface based reflective type polarizer for cross polarization and linear-to-circular polarization conversion with minimal null operation zone","authors":"Raghvenda Kumar Singh;Ashish Gupta;Swarnim Pathak;Preet Singh Sodhi;Akshat Sinha","doi":"10.1029/2025RS008269","DOIUrl":"https://doi.org/10.1029/2025RS008269","url":null,"abstract":"Herein, we put forward an ultra-thin and highly efficient multifunctional wideband reflective polarization converter metasurface for the manipulation of polarization state of the electromagnetic wave. Strong anisotropic characteristics have been achieved by employing a diagonally kept double-sided modified arrow on single layer FR4 substrate backed with copper. Numerical studies show that on one hand, the realized metasurface is capable to convert a linearly polarized (LP) wave (y/x) into its orthogonal counterpart (x/y) over 6.35–9.00 GHz and 15.47–16.03 GHz exceeding 90% polarization conversion ratio. On the other hand, it efficiently transforms the LP wave into reflected circularly polarized (CP) wave over 5.32–6.15 GHz, 9.50–15.22 GHz, and 16.24–17.45 GHz with an axial ratio lower than 3 dB. It is investigated that the type of circular polarization is right-handed over first two above bands while showing left-handed in the last band. Due to the minimum level of tolerance in reflection phases (<22°) with respect to the acceptable limits, the proposed unit-cell exhibits exceptional CP and cross polarization characteristics in the given bands. An array of 33 × 33 unit-cells is created as a prototype and tested experimentally to confirm the suggested structure.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-11"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine magnetotellurics (MT) is a significant geophysical method for probing deep seafloor structures. The dispersive attenuation characteristics of the natural geomagnetic field in dynamic marine environment gives rise to weak signals, which coupled with various noise components, significantly affects the interpretation of the data. To address the issue of composite noise suppression in marine MT signals, this study proposes a denoising method of Multiscale Feature Decoupled Collaborative (Dn-MFDC). Initially, a two-branch deep hierarchical convolutional architecture is constructed to handle multi-source composite noise, optimizing the multi-scale feature representation of marine MT signals via nonlinear mapping. Subsequently, leveraging the multi-scale feature representation of the signal, higher order statistical properties are employed to decouple the noise from the effective signal, achieving statistical independence between them. Finally, experiments are conducted on both synthesized and field marine MT signals. The proposed method effectively mitigates composite noise across varying intensity levels and exhibits superior performance in field data experiments. The results validate the effectiveness and robustness of the proposed method, presenting a novel approach to suppressing composite noise in marine MT signals.
{"title":"A novel denoising method of multiscale feature decoupled collaborative for marine MT signals","authors":"Wanyue Zhang;Yihan Tian;Suyi Li","doi":"10.1029/2025RS008346","DOIUrl":"https://doi.org/10.1029/2025RS008346","url":null,"abstract":"Marine magnetotellurics (MT) is a significant geophysical method for probing deep seafloor structures. The dispersive attenuation characteristics of the natural geomagnetic field in dynamic marine environment gives rise to weak signals, which coupled with various noise components, significantly affects the interpretation of the data. To address the issue of composite noise suppression in marine MT signals, this study proposes a denoising method of Multiscale Feature Decoupled Collaborative (Dn-MFDC). Initially, a two-branch deep hierarchical convolutional architecture is constructed to handle multi-source composite noise, optimizing the multi-scale feature representation of marine MT signals via nonlinear mapping. Subsequently, leveraging the multi-scale feature representation of the signal, higher order statistical properties are employed to decouple the noise from the effective signal, achieving statistical independence between them. Finally, experiments are conducted on both synthesized and field marine MT signals. The proposed method effectively mitigates composite noise across varying intensity levels and exhibits superior performance in field data experiments. The results validate the effectiveness and robustness of the proposed method, presenting a novel approach to suppressing composite noise in marine MT signals.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this communication, a 2 × 2 polarization reconfigurable (PR) sequentially rotated (SR) dielectric resonator antenna (DRA) array is presented to resonate within the IEEE 802.11a band. The array is formed of a novel resonator composed of a rectangular dielectric resonator (RDR) excited by a copper strip of hooked T-shaped monopole to excite two degenerate resonant modes TExδ31 and TEx3δ2 confirming the circular polarization (CP) radiation. The proposed resonating element is optimized to operate at 5.8 GHz with the RDR dimensions being 10 × 5 × 10 mm3. A 2 × 2 array which is formed of the proposed resonator with a feeding circuit constitutes a single Wilkinson power divider (WPD), a single out-of-phase Schiffman coupler, and couple quartile branch line couplers (BLC). The polarization reconfigurability is obtained using positive-intrinsic-negative (PIN) diodes located at the BLC inputs as current switches. With proper PIN diodes switching, the radiated fields can be set to either right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP). To investigate the initiated array resonance performance, an equivalent impedance circuit of the postulated array is proposed based on the array sub-components’ equivalent lumped elements before simulation and measurements. The 100 × 40 mm2 array possessed an impedance bandwidth of 12.07% for RHCP and 12.03% for LHCP within the IEEE 802.11a band. The maximum realized gain was 8.31 dBi with axial ratio (AR) bandwidth of 12.04%. The obtained results verified that the suggested array can emit two CP conditions with reasonable accord between the simulated and measured ones.
{"title":"A 2 × 2 sequentially rotated polarization reconfigurable dielectric resonator antenna utilizing switchable feed circuit for sub-6 GHz applications","authors":"Y. Qasaymeh;O. Alharbi;M. Othman","doi":"10.1029/2025RS008225","DOIUrl":"https://doi.org/10.1029/2025RS008225","url":null,"abstract":"In this communication, a 2 × 2 polarization reconfigurable (PR) sequentially rotated (SR) dielectric resonator antenna (DRA) array is presented to resonate within the IEEE 802.11a band. The array is formed of a novel resonator composed of a rectangular dielectric resonator (RDR) excited by a copper strip of hooked T-shaped monopole to excite two degenerate resonant modes TE<sup>x</sup><inf>δ31</inf> and TE<sup>x</sup><inf>3δ2</inf> confirming the circular polarization (CP) radiation. The proposed resonating element is optimized to operate at 5.8 GHz with the RDR dimensions being 10 × 5 × 10 mm<sup>3</sup>. A 2 × 2 array which is formed of the proposed resonator with a feeding circuit constitutes a single Wilkinson power divider (WPD), a single out-of-phase Schiffman coupler, and couple quartile branch line couplers (BLC). The polarization reconfigurability is obtained using positive-intrinsic-negative (PIN) diodes located at the BLC inputs as current switches. With proper PIN diodes switching, the radiated fields can be set to either right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP). To investigate the initiated array resonance performance, an equivalent impedance circuit of the postulated array is proposed based on the array sub-components’ equivalent lumped elements before simulation and measurements. The 100 × 40 mm<sup>2</sup> array possessed an impedance bandwidth of 12.07% for RHCP and 12.03% for LHCP within the IEEE 802.11a band. The maximum realized gain was 8.31 dBi with axial ratio (AR) bandwidth of 12.04%. The obtained results verified that the suggested array can emit two CP conditions with reasonable accord between the simulated and measured ones.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 8","pages":"1-19"},"PeriodicalIF":1.5,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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