S. Zainud-Deen, K. R. Mahmoud, S. Ibrahem, A. Shaalan
{"title":"Multifilar-curl antenna","authors":"S. Zainud-Deen, K. R. Mahmoud, S. Ibrahem, A. Shaalan","doi":"10.1109/NRSC.2002.1022607","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022607","url":null,"abstract":"Multifilar-curl antennas that can radiate circularly polarized waves are analyzed in detail. The antenna is fed directly or electromagnetically coupled by an inverted-L wire section to improve its impedance matching. The method of moments (MoM) is used to model the antenna structure in the presence of an infinite ground plane. The radiation characteristics of a single curl antenna are compared with available measurements to validate the analysis. A quadrifilar-curl antenna on an infinite ground plane is considered. The current distribution along the antenna, the radiation patterns, the axial ratio, the antenna gain, the input impedance, and VSWR are calculated. An octafilar-curl antenna on an infinite ground plane is proposed to increase the gain of the antenna and to improve the circular polarization characteristics. Also, quadrifilar- and octafilar-curl antennas without a ground plane are presented. The radiation characteristics are calculated. The frequency response of the input impedance, VSWR and the antenna gain are depicted.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"374 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133274189","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":"Quadrature partial response direct-sequence spread spectrum for land mobile satellite communication channel","authors":"G. Abdel-Hamid","doi":"10.1109/NRSC.2002.1022644","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022644","url":null,"abstract":"The paper is concerned with evaluating the performance of a quadrature partial response direct sequence spread spectrum (QPR/DS) signaling when transmitted through a land mobile satellite channel. The channel exhibits fading and shadowing as well as additive white Gaussian noise. Fading and shadowing cause both envelope and phase variations of the received signal. The paper derives upper bounds of the probability of error due to both of these variations, numerical results are obtained for both spread-spectrum and narrow-band land-mobile satellite communication channel with QPR modulation. The derived expressions are useful for the design of land mobile satellite data communication systems.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127427370","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":"FCMA/DSMA for mobile communications","authors":"M. Ali","doi":"10.1109/NRSC.2002.1022632","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022632","url":null,"abstract":"M-ary FCMA and FCMA/DSMA. systems are proposed for third generation mobiles. Either the low orbit satellites or ordinary base-stations can be used to switch information for various users all over the world. Huge population, large capacity, simple access, universal identification, and higher spectral efficiency are amongst FCMA system characteristics together with new adaptive modulation and international roaming features. Many design aspects of M-ary FCMA and FCMA/DSMA for mobile communications are presented. The optimum configuration of M-ary FCMA, the permissible number of simultaneous mobile channels and the spectral efficiency are also evaluated.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"315 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114778807","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":"Effects of geometrical parameters, loading, and feeding on nonuniform helical antennas","authors":"H. Elkamchouchi, A. Salem","doi":"10.1109/NRSC.2002.1022610","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022610","url":null,"abstract":"In this paper, analysis and design methods are applied on helical antenna by using the NEC commercial code based on the method of moments. When adding a ground plane, the linear helix gives a 20 dB gain compared to a 17 dB gain obtained from exponential helix without a ground plane. The feeding of the helix is changed by varying the pitch and studying its effect on the radiation characteristics. Also the helices of uniform and nonuniform profiles are loaded at different positions by different values of resistances and inductances. In this case, the current distribution is computed, and the electric field in the vertical plane and the gain are investigated. Finally, many exponential profiles have been examined for improved characteristics by changing the pitch angle /spl alpha/ of the exponential helix and studying the resulting effect on the antenna characteristics.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124338140","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 generalized network formulation for a circular aperture in conducting plane","authors":"K. Kabalan, A. El-Hajj, A. Rayes","doi":"10.1109/NRSC.2002.1022609","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022609","url":null,"abstract":"The electric field integro-differential equations for electromagnetic scattering from a perfectly conducting plane perforated by a circular aperture is solved by the method of moments. The problem is formulated as an operator equation, where the unknown is the equivalent magnetic current over the aperture and the known is the tangential magnetic field over the aperture region for the complete conducting plane i.e, aperture shorted. Finally, a matrix method of solution is described and a numerical solution is obtained. Several numerical results are shown for illustration.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121482227","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":"Performance and feasibility of different switched-beam antennas for the stratospheric platform mobile communications covering newly developing regions","authors":"M. Nofal, M. Dessouky, M. Hadhood, Y. Albagory","doi":"10.1109/NRSC.2002.1022614","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022614","url":null,"abstract":"Extending the mobile radio service to the newly developing regions is necessary for accelerating their economic and social progress. The cost and flexible deployment of such communication systems are the key issues. The emerging technology of stratospheric platform mobile communications is devised for covering such regions. Introducing smart antenna technology with this kind of communication systems provides additional improvements. The paper suggests several switched-beam smart antenna techniques in order to increase the user location accuracy especially in emergency situations, reduce power consumption, efficiently use the radio spectrum and reduce the errors resulting from the positional instability of the platform. In addition, the performance and feasibility of such approaches in terms of the hardware and processing requirements are addressed. The study dictates the adoption of beam-splitting approach as a superior one due to its compromise between the hardware and processing requirements.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"193 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121527798","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}
Demchenko V. V, Sh. M. Khalil, K. El-Shorbagy, Zaki
{"title":"Separation method: a tool to investigate the problem of absolute parametric instability in a nonuniform bounded plasma","authors":"Demchenko V. V, Sh. M. Khalil, K. El-Shorbagy, Zaki","doi":"10.1109/NRSC.2002.1022672","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022672","url":null,"abstract":"Using the separation method, the effect of 1D and 2D plasma non-uniformity on absolute instability (ABI) of electrostatic waves in a magnetized pumped plasma is investigated in plane geometry. The reflection of such waves along the waveguide is studied. Growth rates of the periodical and aperiodical ABI are reduced due to plasma nonuniformity.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116973216","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":"Analysis and characterization of package resonance","authors":"E. El-Sharawy, H. Ghouz","doi":"10.1109/NRSC.2002.1022604","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022604","url":null,"abstract":"This paper presents FDTD analysis and prediction of the overall effects of the resonance in MIC and MMIC electronic packaging. Practical structures that result in strong resonance effects are investigated such as coupled cross lines with a via transition (STML - single via transition on multiple lines), and multiple via transitions on a single line (MTSL). A detailed study of the mutual coupling, including the resonance effects, has also been performed and is presented. Results of the analysis indicate that the package performance can be very sensitive to resonance effects. A broadband equivalent circuit model for multiple transition discontinuities (two via holes) on a single line has been developed and is presented. There is good agreement between the predicted frequency response of the FDTD and the circuit models over a broad band of frequencies. The analysis presented gives an insight into the limits at which coupling effects on the overall package performance can be neglected. The equivalent circuit model presented can greatly simplify the analysis and simulation of a complex package which includes several transition discontinuities, assuming that the coupling is small.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131965280","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}
E. Saad, M. El-Adawy, M. E. Abu-El-Wafa, A. A. Wahba
{"title":"A multifeature speech/music discrimination system","authors":"E. Saad, M. El-Adawy, M. E. Abu-El-Wafa, A. A. Wahba","doi":"10.1109/NRSC.2002.1022623","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022623","url":null,"abstract":"This paper presents a new technique for the automatic classification of audio signals into either speech or music signal. The classification is based on the most efficient five features extracted from the input signal. The correct classification ratio is always better than that using previous algorithms.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131813775","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":"Centralized adaptive MMSE detectors for multirate DS-CDMA in multipath fading channels","authors":"Mostafa El-Khamy, S. Elnoubi, O. Alim","doi":"10.1109/NRSC.2002.1022645","DOIUrl":"https://doi.org/10.1109/NRSC.2002.1022645","url":null,"abstract":"Future mobile systems will support services with different data rates. In this paper, we propose centralized feed-forward feedback architectures for adaptive minimum mean square error (MMSE) detectors for asynchronous multirate direct sequence code division multiple access (DS-CDMA) systems. A multipath Rayleigh fading channel is assumed. The MMSE detector is implemented using the recursive least squares (RLS) algorithm. We compare between the different. proposed architectures and the results are verified using simulations.","PeriodicalId":231600,"journal":{"name":"Proceedings of the Nineteenth National Radio Science Conference","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124950867","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}