2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)最新文献

{"title":"An MF/HF antenna array for ionospheric sounding and measurement of ionospheric radio emissions","authors":"B. Isham","doi":"10.1109/USNC-URSI-NRSM.2013.6525062","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525062","url":null,"abstract":"The Interamerican Radio Array, to be installed at the Interamerican University campus in Aguadilla, Puerto Rico, is intended to be used for broad-band medium and high-frequency (roughly 2 to 20 MHz) radar imaging of the ionosphere in collaboration with the University of Colorado Versatile Ionospheric Pulsed Radar (VIPR) transmitter in Cayey, Puerto Rico, 109 km distant, and with researchers using the Arecibo Observatory, which lies on a direct line between Aguadilla and Cayey. The Interamerican array will also be used for imaging of ionospheric radio emissions stimulated by the new Arecibo Observatory high-power high-frequency radio transmitter. The Interamerican array will initially have 8 receiving channels, easily expandable to 16 channels, with relatively easy further expansion to 32 and 48 channels. It will initially have about 16 antenna tower locations, also expandable. The basic array will have two crossed 130-meter-long arms each consisting of distributed dipole antennas with linear polarizations, and several antenna locations between the arms. The goals of the project include collaborative ionospheric research with the Cayey and Arecibo Observatories and the development of radio sounding, polarization, interferometry, and imaging techniques using innovative antenna and array designs.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127047745","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}

{"title":"Considerations of high power electromagnetics (HPEM) transients with respect to Smart Grid","authors":"W. Radasky, G. Koepke","doi":"10.1109/USNC-URSI-NRSM.2013.6525041","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525041","url":null,"abstract":"As part of the Smart Grid Interoperability Panel (SGIP) work, Electromagnetic Compatibility (EMC) was introduced as an integral process for the design of devices that will be used as part of the Smart Grid. This resulted in the formation of the Electromagnetic Interoperability Issues Working Group (EMII WG). This working group has produced a draft report that evaluates the electromagnetic environment for new electronic devices to be introduced into the Smart Grid of the future. This evaluation is needed to determine if existing EMC immunity standards are available now or whether new standards need to be developed.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":" 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120830543","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}

{"title":"Microwave spectral line model development: A retrospective in honor of Dr. Hans J. Liebe","authors":"A. Gasiewski, E. Westwater, P. Rosenkranz","doi":"10.1109/USNC-URSI-NRSM.2013.6525006","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525006","url":null,"abstract":"The quantum mechanical basis for microwave spectral line models of oxygen and water vapor absorption as used in radio astronomy, Earth and planetary remote sensing, and telecommunications can be traced to the work of J.H. Van Vleck in 1934, and extended by Van Vleck and V.F. Weisskopf (1945), G. Herzberg (1950), then more fully studied by C.H. Townes and A.L. Schawlow (1955), M.W.P Strandberg (1954), and others. The extensive impact of spectral line models in radiowave propagation is ubiquitous, and seen in the design of virtually all microwave radar, radiometer, navigation, and communication, systems, as well as in many devices such as lasers, masers, fiber amplifiers, and atomic clocks used for precision timekeeping. However, the early spectral line models required a more complete empirical characterization of the absorptive and refractive line parameters for water vapor and oxygen than available using approximate solutions to the problem of interacting fields and distributions of gas molecules.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"27 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120854379","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}

{"title":"EBG-dipole array antenna creating beam-tilt for base-station applications","authors":"Ilkyu Kim, Y. Rahmat-Samii","doi":"10.1109/USNC-URSI-NRSM.2013.6525029","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525029","url":null,"abstract":"Summary form only given. For a typical base-station, tilted beam towards the ground has been employed in order to increase the signal reception from the mobile device. This can be realized with either an electronically controlled phased array antenna or a mechanically tilted array antenna. These techniques have been used; however, there exists inherent shortcomings with respect to performance at a tilted angle and practical implementation. For a common phased array, an array pattern is tilted toward a desired direction while element pattern stays toward the broadside. This mainly results in antenna gain reduction at the tilted angle. For the mechanically adjusted array, careful and stable installation is often required, which sometimes make it difficult to implement. Therefore, an enhancement in the conventional basestation array antenna is needed in order to achieve improved antenna performance with robust implementation. In this paper, a novel base-station array element design that consists of a single dipole mounted on an EBG ground plane is presented. Each dipole on an EBG structure provides tilted radiation pattern. This is achieved by employing 6×6 cell miniaturized EBG structure that is modified by connecting four of its unit cells. This EBG structure allows a low profile, high directivity, and beam-tilting single element design. With this dipole-EBG element, the radiation pattern can be steered from the broadside to the desired tilted angle which is suitable for the base-station applications. Based on the element design, an array antenna with four dipole-EBG elements is designed in order to verify the base-station like antenna performance. A down-tilt array pattern incorporated with a progressive phase is utilized in the array along with the tilted element pattern. To validate the proposed array, similar array that consists of non-modified standard EBG unit cell (a broadside element pattern) is employed as a reference. It is observed that the proposed array, compared to the reference case, achieves better performance with respect to the gain and sidelobe characteristics. The proposed EBG-dipole element incorporated into an array antenna is simulated using full-wave simulator. The proposed EBG antenna operates at 3.5 GHz, which covers part of WiMAX service bands. The directivity of more than 11.5 dB is obtained at the down-tilted angle of 25°. An impedance matching better than -10 dB S-parameter is attained across a reasonable bandwidth. The proposed dipole-EBG element array antenna should allow for performance efficient realization of future base-station antennas.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123879230","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}

{"title":"GNSS reflectrometry using the L5 and E5a signals for remote sensing applications","authors":"S. Powell, D. Akos","doi":"10.1109/USNC-URSI-NRSM.2013.6525020","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525020","url":null,"abstract":"Summary form only given. Signals from the Global Navigation Satellite Systems, GNSS, can be viewed as a passive source of radiation and therefore be used for remote sensing purposes. When reaching a surface, for example the ocean, the signal is reflected off the surface. The reflected signal can be used together with the direct signal to obtain observables such as altitude and wind speed.The strongest reflected signal comes from the specular point, the point on the surface where the angle of incidence and angle of reflection is equal. Signals used for GNSS reflectrometry are scattered from a small area around the specular point, the glistening zone. Analysis of the correlation function for the reflected waveform can provide information about the surface roughness and wind speed. The measured difference in delay between the direct and reflected signal is used to determine the altitude of the receiver. During this work a bistatic system which provides signals in the L1, L2 and L5 bands has been improved and tested. GNSS signals are on incidence right hand circular polarized but when reflected the signals are received by using a left hand circular polarized antenna. This system uses a two stage receiver; the signal is first received with a front-end and thereafter post processed by software. Bistatic post processing software is being developed for GPS L1 and L5 and Galileo E1 and E5a. The primary focus is on L5/E5a signals, which have a ten times higher chipping rate than L1/E1 and will result in a sharper correlation peak and therefore more accurate measurements. The bistatic system was installed and tested on the NOAA BAO tower and GNSS data was collected when satellites for both L5 and E5a signals were visible. The system has been installed on the NOAA P3 aircraft and is expected to provide flight data over the ocean.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124316036","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}

{"title":"First results from the coherent-scatter atmospheric passive radar imager (CAPRI) for passive radio sensing of equatorial plasma instabilities near the Peruvian andes","authors":"B. Tuysuz, J. Urbina, F. Lind","doi":"10.1109/USNC-URSI-NRSM.2013.6525063","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525063","url":null,"abstract":"At equatorial latitudes, near the geomagnetic equator, the detection of coherent scatter echoes from E and F region B-field aligned irregularities (FAI), where the radar k vector is oriented perpendicular to the Earth's magnetic field (B), is relatively easy. Although, the Jicamarca Radio Observatory (PRO) is extremely useful to study the coherent equatorial low-latitude atmosphere and the systems to which they are coupled, alternatively, the detection of field aligned irregularity (FAI) scattering from “transmitters of opportunity” can be utilized using a passive radar receiver system. This approach to monitoring the ionosphere can operate continuously and be used to provide wide spatial coverage of the unstable ionosphere. Also, utilization of the third party transmitters reduce the cost of the instrument and provides diversity in frequency and scattering geometry.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121529140","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}

{"title":"Monte Carlo simulation of neutron generation by lightning leaders","authors":"W. Xu, S. Celestin, V. Pasko","doi":"10.1109/USNC-URSI-NRSM.2013.6525017","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525017","url":null,"abstract":"Summary form only given. Terrestrial Gamma-ray Flashes (TGFs) are high-energy photon bursts originating from the Earth's atmosphere [Fishman et al., Science, 264, 1313, 1994]. Measurements have correlated TGFs with initial development stages of normal polarity intracloud lightning that transports negative charge upward (+IC) [e.g., Lu et al., GRL, 37, L11806, 2010; JGR, 116, A03316, 2011] and it has been suggested that long unbranched +IC lightning leaders could produce a suficient number of energetic electrons during their stepping processes to explain TGFs [Celestin and Pasko, JGR, 116, A03315, 2011]. Moreover, neutron bursts have been observed in association with lightning [e.g., Shah et al., Nature, 313, 773, 1985; Shyam and Kaushik, JGR, 104, 6867, 1999; Bratolyubova-Tsulukidze et al., Adv. Space Res., 34, 1815, 2004]. Additionally, the large amount of energetic photons in TGF events has been suggested to be responsible for the production of neutron bursts [Babich et al., JETP Lett, 84, 285, 2006; Carlson et al., JGR, 115, A00E19, 2010].In the present study, we simulate the acceleration of electrons during the negative corona Hash stage of stepping negative lightning leaders. Energetic photons are produced by these runaway electrons either producing gamma-rays or lower energy X-rays depending on the electric potential difference in the leader head region. We have developed a Monte Carlo model that simulates neutron generation through the photonuclear interaction in the atmosphere. In this work, we quantify the properties of the neutron source possibly generated by different lightning discharges and we also investigate the possibility of neutron generation from typical negative cloud-to-ground lightning discharges.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122570030","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}

{"title":"Ka-band phased array antenna with integrated MEMS phase shifters","authors":"Woon-Gi Yeo, N. Nahar, K. Sertel","doi":"10.1109/USNC-URSI-NRSM.2013.6525141","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525141","url":null,"abstract":"We present a wideband Ka-band phased array antenna with micro electromechanical systems (MEMS) phase shifters integrated directly into the feeding structure of each element. Traditionally, phased arrays use GaAs monolithic microwave integrated circuits (MMIC) phase shifters for beam-steering. However, as the number of array elements grow, MEMS-based phase-shifter technologies become more attractive due to lower insertion loss and very low power consumption. In particular, for a new class of phased arrays developed recently, the large number of elements necessitates use of MEMS-based phase-shifter to minimize total power.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"379 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123450790","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}

{"title":"The undisturbed-field model: A propagation model for close-in distances and very low antenna heights","authors":"N. DeMinco","doi":"10.1109/USNC-URSI-NRSM.2013.6525050","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525050","url":null,"abstract":"This abstract describes a radio-wave propagation model (the Undisturbed-Field Model) that was developed at the Institute for Telecommunication Sciences (ITS). The Undisturbed-Field Model was developed as the result of an investigation to create a short-range mobile-to-mobile propagation model. ITS reviewed and evaluated currently available radio-wave propagation models and came to the conclusion that none of these models were suitable for addressing the requirements of ultra-short distances and very low antenna heights. The results of the work are available in an ITS report.1 In this report, a deterministic method is described which is suitable for a very short-range propagation model for distances of 2 to 30 meters, antenna heights of 0 to 3 meters, and frequencies from 150 to 6000 MHz. The method involves the calculation of the undisturbed electric field and calculation of the loss based on the amplitude of the electric field as a function of distance, frequency, and the ground constants. The undisturbed field is that electric field produced by a transmitter antenna at different distances and heights above ground without any field-disturbing factors in the proximity of the receiver antenna location. This is in contrast to a disturbed field where an antenna located at the receiver site would disturb the electric field. The ITS report1 describes the results in detail of an investigation of the differences between the undisturbed and disturbed (mutual coupling) methods of field computation, and goes on to show the differences between the results of propagation loss computed with both methods. The disturbed-field method is the more exact method, but it is more computationally intensive and difficult to calculate when compared to the relatively simple computations with undisturbed-field method. The ITS report shows via numerous examples that for most scenarios the difference between the propagation loss computed by undisturbed-field method and the disturbed-field method is minimal.1 The undisturbed electric field technique includes near-field effects, the complex two-ray model, antenna heights, ground constants, antenna near-field and far-field response and the surface wave. Since this is a Line-of-Sight model, the ground is assumed to be flat over the distance of 30 meters or less with no irregular terrain present. For distances of less than 5 kilometers the curvature of the Earth has a negligible effect and can be assumed to be flat for frequencies less than 6 GHz over a smooth Earth.1 The Undisturbed-Field Model should be used for distances less than 300 meters. It is particularly applicable for close-in distances less than 30 meters. This presentation will describe the development of the Undisturbed-Field Model and the methods that it uses for calculating propagation loss.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129177239","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}

{"title":"Spatial array processing methods for radio astronomical RFI mitigation","authors":"B. Jeffs, K. Warnick","doi":"10.1109/USNC-URSI-NRSM.2013.6525067","DOIUrl":"https://doi.org/10.1109/USNC-URSI-NRSM.2013.6525067","url":null,"abstract":"Summary form only. Over more than a decade there have been a variety of array signal processing methods proposed for interference canceling in radio astronomical observation. Approaches include adaptive filtering, statistically optimal null-steering beamformers, robust adaptive beamforming, vector subspace partitioning, interference tracking algorithms, and use of auxiliary reference antennas. Conventional imaging arrays are obvious candidates where the spatial signature across all antennas may be used to remove interference directly from the visibility/correlation terms. The new wave of phased array feeds under development (e.g. ASKAP, APERTIF, DRAO, BYU/NRAO, Arecibo) also opens up, to both single dish instruments and synthesis arrays, new possibilities for actively nulling interferers independently at each dish. Low frequency aperture arrays (e.g. LOFAR, MWA, LWA, PAPER) have such wide fields of view and operate in such crowded bands that spatial canceling is almost mandatory. Array signal processing can be used in conjunction with traditional data blanking (or pruning) and frequency avoidance, but if successful the array cancelers will offer the attractive new benefit of continuous operation without data loss in corrupted frequency bands. However, adoption has been very slow. Reasons for delay include 1) costly infrastructure requirements like fast correlator dump times, new digital back end processors, computational burden, array signal transport, and new auxiliary antennas, 2) poor nulling performance for adaptive beamformers, i.e. inability to drive interference 10s of dB below the noise floor, 3) uncertainty about signal of interest distortion while canceling interference, and 4) lack of clear science case where critical observations cannot be made without array processing cancelation methods. This tutorial will present an overview of previously proposed array signal processing RFI mitigation techniques and discuss capabilities and limitations. Newer methods will be presented which achieve significantly deeper nulls and introduce less mainbeam distortion than do typical adaptive beamformers. A “state of the art” review of current practice and discussion of future directions and trends will be presented.","PeriodicalId":123571,"journal":{"name":"2013 US National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM)","volume":"11 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129200741","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}