2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)最新文献_第3页

Advances in implantable and wearable antennas for wireless brain-machine interface systems 无线脑机接口系统中可植入和可穿戴天线的研究进展

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928137

E. Moradi, K. Koski, T. Bjorninen, R. Muller, P. Ledochowitsch, L. Sydanheimo, E. Alon, M. Maharbiz, J. Rabaey, L. Ukkonen, Y. Rahmat-Samii

引用次数: 2

An examination of the source of decameter-scale irregularities in the geomagnetically disturbed mid-latitude ionosphere 地磁扰动中纬度电离层中十米尺度不规则性来源的研究

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/URSIGASS.2014.6929853

E. Thomas, J. Baker, J. Michael Ruohoniemi, K. Hosokawa, P. Erickson, A. Coster, J. Foster

{"title":"An examination of the source of decameter-scale irregularities in the geomagnetically disturbed mid-latitude ionosphere","authors":"E. Thomas, J. Baker, J. Michael Ruohoniemi, K. Hosokawa, P. Erickson, A. Coster, J. Foster","doi":"10.1109/URSIGASS.2014.6929853","DOIUrl":"https://doi.org/10.1109/URSIGASS.2014.6929853","url":null,"abstract":"Summary form only given. We present first results from a study of the relationship between small-scale ionospheric irregularities observed by Super Dual Auroral Radar Network (SuperDARN) radars and large-scale density structures, such as the mid-latitude trough associated with subauroral polarization stream (SAPS) events. A focus is placed on mid-latitudes over North America where recent expansion of the SuperDARN network allows for comparison with total electron content (TEC) measurements from a dense network of ground-based GPS receivers. Numerical models show that gradients associated with the mid-latitude trough walls can produce small scale structures due to both the ion temperature gradient instability and gradient drift instability. However, previous studies of the gradient drift instability using high-latitude SuperDARN radars suggest that only sunward directed plasma density gradients at the duskside and dawnside ends of the trough present favorable conditions for the growth of decameter-scale field-aligned irregularities (FAIs). Recent campaigns by the Millstone Hill Incoherent Scatter Radar in support of the NASA Van Allen Probes mission provide crucial ion/electron velocity, temperature, and density measurements for the study of these instability processes. Specifically, we re-examine the gradient drift instability as a source of the small-scale FAIs regularly observed by SuperDARN radars in the mid-latitude ionosphere during geomagnetically disturbed conditions.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114091783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Antenna functionalities in a cognitive radio environment 认知无线电环境下的天线功能

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6927994

Y. Tawk, J. Costantine, F. Ayoub, C. Christodoulou

引用次数: 0

Scalar potential formulation for a uniaxial inhomogeneous medium 单轴非均匀介质的标量势公式

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6927982

M. Havrilla

{"title":"Scalar potential formulation for a uniaxial inhomogeneous medium","authors":"M. Havrilla","doi":"10.1109/USNC-URSI-NRSM.2014.6927982","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2014.6927982","url":null,"abstract":"Summary form only given. Vector potentials are frequently utilized in the electromagnetic analysis of problems involving simple (i.e., linear, homogeneous, and isotropic) media. In recent decades, various scalar and vector potential formulations have been investigated for the analysis of anisotropic and bianisotropic media. This interest has been greatly influenced by the significant developments in material fabrication capability and the phenomena associated with complex media. Uniaxial anisotropic media are particularly interesting from an application viewpoint due to the relative ease of manufacturing this type of material. The goals of this paper are to first briefly review a scalar potential formulation for a magnetically and electrically uniaxial anisotropic medium. It is assumed the medium is, in general, inhomogeneous along the longitudinal axis (i.e., the zaxis). Next, expected and unexpected depolarizing dyad contributions are identified in the scalar potential development. It is discussed, from a physical viewpoint, why the unexpected depolarizing dyad should not exist. Based on this insight, the final goal is to mathematically demonstrate the unexpected depolarizing dyad is actually removable, thus leading to a physically and mathematically consistent theory.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120967020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

One year of on-orbit performance of the Colorado Student Space Weather Experiment (CSSWE) 科罗拉多学生空间天气实验(CSSWE)在轨运行一年

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928087

S. Palo, D. Gerhardt, Xinlin Li, L. Blum, Q. Schiller, R. Kohnert

{"title":"One year of on-orbit performance of the Colorado Student Space Weather Experiment (CSSWE)","authors":"S. Palo, D. Gerhardt, Xinlin Li, L. Blum, Q. Schiller, R. Kohnert","doi":"10.1109/USNC-URSI-NRSM.2014.6928087","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2014.6928087","url":null,"abstract":"The Colorado Student Space Weather Experiment is a 3-unit (10cm × 10cm × 30cm) CubeSat funded by the National Science Foundation and constructed at the University of Colorado (CU). The CSSWE science instrument, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), provides directional differential flux measurements of 0.5 to >3.3 MeV electrons and 9 to 40 MeV protons. Though a collaboration of 60+ multidisciplinary graduate and undergraduate students working with CU professors and engineers at the Laboratory for Atmospheric and Space Physics (LASP), CSSWE was designed, built, tested, and delivered in 3 years. On September 13, 2012, CSSWE was inserted to a 477 × 780 km, 65° orbit as a secondary payload on an Atlas V through the NASA Educational Launch of Nanosatellites (ELaNa) program. The first successful contact with CSSWE was made within a few hours of launch. CSSWE then completed a 20 day system commissioning phase which validated the performance of the communications, power, and attitude control systems. This was immediately followed by an accelerated 24 hour REPTile commissioning period in time for a geomagnetic storm. The high quality, low noise science data return from REPTile is complementary to the NASA Van Allen Probes mission, which launched two weeks prior to CSSWE. On September 13, 2013, CSSWE completed one year of on-orbit operations. In this talk we will discuss the issues encountered with designing and operating a cubesat in orbit. Data from the mission will be presented and discussed in the larger context of ionospheric and magnetospheric physics.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131587857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A simple wireless power transfer scheme for implanted devices 一种用于植入设备的简单无线电力传输方案

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928003

Shyam C. Nambiar, M. Manteghi

引用次数: 4

MITEoR: A prototype highly scalable interferometer for 21 cm cosmology MITEoR:用于21厘米宇宙学的高度可扩展干涉仪原型

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928124

J. Dillon, Haoxuan Zheng, Max Tegmark

引用次数: 0

Modeling the role of atmosphere on the duration of non-specular meteor trails 模拟大气对非镜面流星轨迹持续时间的作用

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928098

F. Galindo, J. Urbina, L. Dyrud, J. Fentzke

{"title":"Modeling the role of atmosphere on the duration of non-specular meteor trails","authors":"F. Galindo, J. Urbina, L. Dyrud, J. Fentzke","doi":"10.1109/USNC-URSI-NRSM.2014.6928098","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2014.6928098","url":null,"abstract":"Summary form only given. Recent papers by Hinrichs et al., (2009) and Dyrud et al., (2011) discuss how non-specular meteor radar reflections can vary due to atmospheric parameters. This theoretical simulator models the evolution of an individual meteoroid into the atmosphere, including ablation, ionization, thermal expansion and plasma stability based upon the meteor Farley-Buneman Gradient-Drift (FBGD) instability. They demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends for non-specular meteor trails. In this paper we present a detailed analysis of the role that atmospheric and ionospheric parameters such as ionospheric plasma density, termospheric winds, etc. have on the development of meteor trail turbulence and evolution. Our work is an extension of the research described in Hinrichs et al., (2009), and Dyrud et al., (2011). Preliminary results show that the trail duration exhibits a linear dependency with changes (up to one order of magnitude) in the ionospheric plasma density. Larger variations in the ionospheric plasma density produce exponential changes in trail duration. For example, a 1 μg meteoroid moving at 35 km/s produces a trail duration of 5.7 s while the same meteoroid can last 0.85 s if the ionospheric plasma density changes by a factor of 10. These simulations are validated with meteor data collected with the University of Illinois Portable Radar that was installed in Fort Macon, North Carolina (34° N, 65° W). The antenna beam was pointed 26° West of the magnetic north, and at an elevation angle of 16o. The antenna bore-sight was aimed perpendicular to the Earth's magnetic field.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114511149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Characterization of electromagnetic fields in complex systems through phase-space techniques 通过相空间技术表征复杂系统中的电磁场

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928025

G. Gradoni, S. Creagh, G. Tanner

{"title":"Characterization of electromagnetic fields in complex systems through phase-space techniques","authors":"G. Gradoni, S. Creagh, G. Tanner","doi":"10.1109/USNC-URSI-NRSM.2014.6928025","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2014.6928025","url":null,"abstract":"Summary form only given. In this presentation, we describe how field-field correlation functions may be efficiently propagated using ideas based on ray propagation. The key point is to make a connection between the field-field correlation function and the corresponding Wigner function, which is obtained from it by Fourier transformation. The Wigner function underlying this approach originated in quantum mechanics, where it can be used to make an analogy between the evolution of the wavefunction and the evolution in phase space of the underlying classical trajectories. In the context of EM problems, the Wigner-function approach has been championed by Marcuvitz using the “quasiparticle” picture of wave evolution (N. Marcuvitz, Proc. IEEE, 79-10, 1991). In the approach we propose, to approximate the propagation of field-field correlation functions by propagating phase-space densities of ray families, which is effectively a lower-dimensional calculation and therefore easier to compute. As an example, we consider a model problem in which the field-field propagator is evaluated in free space. For the case of short source correlation, an approximate solution is presented in terms of a map in phase-space, called as Perron-Frobenius operator. The solution works from the nearto the far-field and serves as a proofof-principle for propagation in more complex environments. The limitations of the approximate solution are also discussed. In particular, the Wigner-function approach can be extended to boundary-value problems by using the results of the random matrix theory. We show that this philosophy has common aspects with that adopted in the formulation of the Maryland Random Coupling Model for complex electromagnetic enclosures.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"13 19","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113931542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tomographic reconstruction of simulated two-dimensional propagation data 模拟二维传播数据的层析重建

2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM) Pub Date : 2014-10-20 DOI: 10.1109/USNC-URSI-NRSM.2014.6928063

C. Rino

{"title":"Tomographic reconstruction of simulated two-dimensional propagation data","authors":"C. Rino","doi":"10.1109/USNC-URSI-NRSM.2014.6928063","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2014.6928063","url":null,"abstract":"The forward propagation equation (FPE) has been used extensively for simulating ionospheric propagation data. However, for most applications the structured region has been replaced by an equivalent phase screen. This allows fully three-dimensional simulations under strong-scatter conditions, but it does not capture detail with sufficient fidelity to support tomographic reconstruction. The problem is compounded by the fact that field-aligned structure extends to altitudes approaching 1000 km. To meaningfully populate a data space with representative structure over the full range of scale sizes is challenging in its own right, but a two-dimensional slice captures the essential attributes of propagation through highly extended structure. Tomographic reconstruction makes use of multiple propagation paths that intersect a common ionospheric volume. A modified form of the FPE reproduces data from a receiver at the ground intercept of the ray from the source. The nominal propagation angle is local reference. While most simulations have concentrated on realizations of a single receiver, varying the propagation direction is equivalent to reception by a displaced receiver. With care to manage the phase relations, one can generate data representative of multiple widely separated receivers. Moreover, because the FPE contains additive differential diffraction and structure components, the diffraction term can be bypassed to generate the path integration that forms the basis of tomographic reconstruction schemes.","PeriodicalId":277196,"journal":{"name":"2014 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117299523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0