2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)最新文献

{"title":"Physical Layer Security under Accumulated Harvested Energy from RF Source","authors":"Shashibhushan Sharma, Sanjay Dhar Roy, S. Kundu","doi":"10.23919/URSIAP-RASC.2019.8738353","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738353","url":null,"abstract":"In this paper, we have studied the accumulation of harvested energy, at decode and forward (DF) relays over several frames, which is used by the relays to forward the signal in a particular frame in presence of a passive eavesdropper. The source broadcasts the information signal to DF relays in the broadcasting phase. Each relay is assisted with two omnidirectional antennas, while the source and the destination is assisted with a single omnidirectional antenna. The selected relay uses the signal received from one antenna to harvest energy, while it uses the received signal from another antenna to decode the message. At the relay, the harvested energy in each frame of communication might not be sufficient to forward the signal, which requires accumulation of energy. The accumulated energy over several frames becomes sufficient to forward the signal to the destination in a particular frame through a single antenna in the relaying phase, while the eavesdropper tries to eavesdrop the relayed information signal. We evaluate the secrecy outage probability in the proposed network to secure the information signal at the physical layer when the selected relay transmits using accumulated harvested energy. The secrecy performance increases with an increase in transmit power of the source, and the number of the frames used for energy accumulation. A closed-form expression on secrecy outage probability under accumulation of harvested energy is developed which is verified by MATLAB based simulation.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128143942","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 impact of curvature on surface current near the rounded corners of a scatterer.","authors":"P. Smith, A. Markowskei","doi":"10.23919/URSIAP-RASC.2019.8738501","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738501","url":null,"abstract":"When a perfectly electrically conducting two-dimensional scatterer, which is smooth except at finitely many sharp corner points, is illuminated by an E-polarised electromagnetic plane wave, the surface current density exhibits singularities at those corner points, whilst in the H-polarised case the surface density exhibits singularities in its derivative at those points. Once the corners are rounded, the surface density becomes non-singular. It is of interest to examine the impact of this rounding upon the surface current and other observed physical quantities such as the far-field, as the rounding becomes more pronounced.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"276 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122260124","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":"Positive-Negative Array-Element Based Single-Antenna Full-Duplex Self-Interference Mitigation","authors":"Wenchi Cheng, Jianyu Wang, Hailin Zhang","doi":"10.23919/URSIAP-RASC.2019.8738653","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738653","url":null,"abstract":"Full-duplex (FD), where the terminal transmits and receives signals simultaneously using the same frequency-band and time-slots, has been treated as one of the potential candidate techniques to enhance the spectrum of future wireless communications. However, one of critical problems in wireless FD communications is how to efficiently mitigate the self-interference (SI) while achieving the maximum spectrum efficiency. In this paper, we develop novel positive-negative array-element based SI mitigation scheme for wireless FD communications. In particular, we formulate the system model for positive-negative array-element based SI mitigation scheme. Then, based on the system model, we analyze the performance of the SI mitigation scheme. Simulation results verify our theoretical analyses and show that our developed SI mitigation schemes can significantly reduce SI for wireless FD communications.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127912841","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":"Application of PS-InSAR Technique for Measuring the Coastal Subsidence in the East Coast of South Korea","authors":"K. Suresh, Duk‐jin Kim, Jungkyo Jung, Yang‐Ki Cho","doi":"10.23919/URSIAP-RASC.2019.8738313","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738313","url":null,"abstract":"Subsidence is a widespread phenomenon caused by both natural and anthropogenic activities, particularly in the coastal areas. Eventually, the impact of coastal subsidence can affect the monitoring of sea level rise by in-situ tidal gauge stations. The Korean peninsula is one of such areas that reported considerably rapid sea level rise than the global average in the recent years. Therefore, there is a need for assessing the land subsidence component of relative sea level rise for better future prediction models. Space borne Interferometric SAR technique provides millimeter level of accuracy in displacement measurements. The objective of this study is to estimate the earth’s surface movements along the coastal areas of Pohang, South Korea. To achieve that, we acquired C-band Sentinel-1 data during 2016 – 2017. Time-series Stanford Method of Persistent Scatter (StaMPS) InSAR analysis proved technique to measure displacements at highresolution with reduced decorrelation noise from interferograms. The results showed about 1.83 cm/year subsidence in the Pohang coastal area, whereas significant sea level rise is observed in this region. The results will provide further insight into the localized subsidence rates in the study sites and its impact on the sea level monitoring.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132406889","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":"MeerKAT","authors":"J. Jonas","doi":"10.1109/ursigass.2014.6929996","DOIUrl":"https://doi.org/10.1109/ursigass.2014.6929996","url":null,"abstract":"The first phase of the MeerKAT radio telescope [4] has been installed on the Karoo site. This phase includes all 64 antennas fitted with L-band receivers and digitizers, signal and data transfer systems, time and frequency reference, the correlator/beamformer hardware, control software, and science data processing hardware and software, Not all of the functionality required to execute the eight large scale projects (LSPs) that have been prioritized is available at the moment, but commissioning and test observations have been conducted using the L-band receivers and the first correlater/beamformer firmware releases. Test images of the Galactic Centre, the Galactic Plane and deep extragalactic fields indicate that all of the telescope subsystems are functioning correctly, and specifically that the analog and digital signal paths (including the dish optics) are operating operating within specification. The sensitivity of the L-band instrument is twice that initially specified in the call for large survey projects [1].","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132511422","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":"Electromagnetic Waves Guided by an Array of Parallel Gyrotropic Cylinders","authors":"V. A. Es'kin, Vladislav I. Zhelezov, A. Kudrin","doi":"10.23919/URSIAP-RASC.2019.8738143","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738143","url":null,"abstract":"The propagation of electromagnetic waves guided by an array of parallel identical cylinders that are filled with a gyrotropic medium and placed in free space is studied. It is assumed that the gyrotropic medium is a cold magnetoplasma and the cylinders are aligned with an external static magnetic field. It is shown that a guiding structure consisting of several identical gyrotropic cylinders supports the propagation of a greater number of modes than a single-cylinder waveguide. Conditions are found under which the mutual influence of the cylinders can be neglected when calculating the properties of the guided modes.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130118309","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":"A Ray Analysis of the Radiation by Realistic Small Antennas Mounted Directly on Large Locally Convex Platforms","authors":"P. Pathak, K. Phaebua","doi":"10.23919/URSIAP-RASC.2019.8738565","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738565","url":null,"abstract":"A Uniform Geometrical Theory of Diffraction (UTD) ray approach has been used successfully, in the past, to predict the high frequency radiation by infinitesimal electric or magnetic current moments of constant strength, which are placed directly on locally convex but otherwise relatively arbitrary shaped electrically large structures, such as aircraft, missile, or spacecraft geometries. However, there is currently a need for modeling platform mounted, electrically small, realistic, and hence complex (or inhomogeneous) antennas whose radiation characteristics are significantly different from those of tiny constant current moments. Some examples of the latter complex radiators are various types of printed antennas, including spirals, as well as a variety of cavity backed antennas, and so on. One notes that a conventional numerical based solution, albeit more rigorous for the present problem, is unable to provide a physical picture for the radiation mechanisms which the UTD can provide; furthermore, unlike the UTD, conventional numerical techniques can also become highly cumbersome, if not intractable, for large realistic platforms. A preliminary UTD solution to the present problem was discussed recently by the authors (at ISAP 2017, Phuket, Thailand). Here, that work is better formalized and applied to more variety of antennas. In this present UTD approach, the far field of any realistic small antenna on a flat ground plane is first obtained via a commercial simulation software, or appropriate measurements. The latter field is asymptotically matched in the deep lit zone of the antenna to a well known analytical UTD solution for a point source placed on a locally convex surface where the original antenna is to be mounted. A resulting equivalent UTD type point source, whose strength depends on the aspect in the lit zone, can thus be systematically identified for modeling the complex antenna as will be described in detail. Such an equivalent UTD point source can now be placed at the antenna location on the actual structure of interest to in turn provide an accurate UTD based radiation pattern of that antenna in the presence of the same structure. A theoretical basis for the present UTD approach, and numerical examples based on it, will be presented to demonstrate the simplicity, utility, and accuracy of the method.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130225544","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":"Generation of ultralow-phase-noise millimeter-wave signal using an electro-optics-modulation comb","authors":"A. Ishizawa, T. Nishikawa, K. Hitachi, H. Gotoh","doi":"10.23919/URSIAP-RASC.2019.8738185","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738185","url":null,"abstract":"Future wireless telecommunications and coherent radar systems will use the millimeter-wave (MW) band. For achieving these applications, the phase-noise reduction of signal generator (SG) will be important. Several low-phase-noise MW generation methods based on photonic technologies [1] have been reported. Since these methods need a laser cavity, the repetition frequency is almost fixed, and its tunable range is narrow. We show the novel method to greatly reduce the phase noise of standard SGs. In general, the phase noise of a SG becomes larger as the MW frequency increases. In this work, we show that the phase noise of a standard SG can be reduced using an electro-optics-modulation (EOM) comb [2].","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133913741","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":"Influence of Gold Nanoparticles (GNPs) on Radiofrequency Tissue Heating","authors":"G. Chakaravarthi, A. K. Narasimhan, M. S. Ramachandra Rao, K. Arunachalam","doi":"10.23919/URSIAP-RASC.2019.8738526","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738526","url":null,"abstract":"Radio Frequency (RF) heating of Gold nanoparticles (GNPs) for hyperthermia is presented. RF heating experimental study was carried out at 915 MHz for phosphate buffer solution (PBS) with and without 10 nm GNPs in muscle phantom. Influence of GNPs on radiated heating was investigated for 10 and 20 W input power. The phantom heating rate was similar for the control (only PBS) and PBS with GNPs. Experimental results showed that the buffer solution with and without the GNPs heated alike indicating no enhancement in RF heating.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131806311","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":"Q-factor enhancement of open 2D resonators by placement of thin metallic rods near the aperture.","authors":"E. Vinogradova, P. Smith","doi":"10.23919/URSIAP-RASC.2019.8738620","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738620","url":null,"abstract":"Thin metallic rods or wires are often used for tuning slotted resonators and waveguides. A vast number of publications have appeared in the literature and some of the approaches are exemplified in references [1– 5]. In this paper we consider a perfectly electrically conducting two-dimensional slotted cylindrical cavity of arbitrary cross-section, and a thin metallic rod or wire aligned with the axis of the cavity, also of arbitrary cross-section. The structure is illuminated by an E-polarised time-harmonic electromagnetic plane wave, incident from some specified direction.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129398578","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}