Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462)最新文献_第5页

Thinned multi-ring arrays using genetic algorithms 使用遗传算法的薄多环阵列

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929177

S. El-Khamy, M. Lotfy, M. H. Ramadan, A. El-Tayeb

{"title":"Thinned multi-ring arrays using genetic algorithms","authors":"S. El-Khamy, M. Lotfy, M. H. Ramadan, A. El-Tayeb","doi":"10.1109/NRSC.2001.929177","DOIUrl":"https://doi.org/10.1109/NRSC.2001.929177","url":null,"abstract":"Electromagnetic optimization problems generally involve a large number of parameters. Traditional optimization methods are not well suited for optimizing a large number of discrete parameter. This paper focuses on a relatively new approach to optimization, namely, the generic algorithm (GA). Thinning of large antenna arrays is an example of sophisticated multi-parameter optimization problems. In addition to reducing cost and complexity, thinning (randomizing) removes the periodicity in the array excitation and hence results in the cancellation of grating lobes and the possible reduction of sidelobes of the array. This paper deals with the optimal thinning of large planar arrays of the original multi-ring structure using genetic algorithms. The genetic algorithm determines which elements are turned off in a periodic ring array to yield the lowest maximum relative sidelobe level. As an example the paper describes simulation of the proposed technique for a 64-element ring area. The considered original ring array is considered to be excited by two aperture techniques sampling methods described in a previous work. The results shows that the thinned ring array enjoys much lower sidelobe levels, and hence are of great engineering importance.","PeriodicalId":123517,"journal":{"name":"Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122786476","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: 6

Statistical multiplexing gain: direct estimation and its application to admission control in ATM networks 统计复用增益:直接估计及其在ATM网络准入控制中的应用

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929407

G. Khalaf, S.S.K. El-Yamany

引用次数: 2

Modified back propagation algorithm for learning artificial neural networks 改进的反向传播算法用于学习人工神经网络

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929244

W. Ahmed, E. Saad, E. Aziz

引用次数: 19

Helical antennas with nonuniform helix diameter 螺旋直径不均匀的螺旋天线

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929187

H. Elkamchouchi, A. Salem

引用次数: 6

Dipole enhanced characteristics using nonconventional metallic reflectors 利用非常规金属反射器增强偶极子特性

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929190

H. Elkamchouchi, M. N. Abd El-Salam

{"title":"Dipole enhanced characteristics using nonconventional metallic reflectors","authors":"H. Elkamchouchi, M. N. Abd El-Salam","doi":"10.1109/NRSC.2001.929190","DOIUrl":"https://doi.org/10.1109/NRSC.2001.929190","url":null,"abstract":"The earliest cellular antennas were fairly simple radiation platforms such as omnis, corner reflectors and panel antennas. In these halcyon days of low subscriber densities, seemingly infinite available bandwidth (courtesy of the single PSTN-owned carrier philosophy) and humble subscriber demands, these simple antennas fared well. A number of factors changed all this in the late eighties. The mass appeal of the mobile market started to bite, dramatically increasing subscriber densities. The era of the single PSTN-owned cellular operator drew to a close, heralding a new age of competitive deregulation, with multiple operators each allowed a specific narrow spectrum. Network planners began to feel the squeeze. To meet new network demands, entirely new antennas systems were required-antennas with improved flexibility, more precise cell coverage and reduced total cost. In this paper the radiation characteristics of simple antenna forms i.e. dipoles were highly improved using non-conventional reflectors. Consequently any antennas used in base stations that can be mounted with the same technique can be highly improved with a relatively low cost.","PeriodicalId":123517,"journal":{"name":"Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133774527","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

Performance of code division multiple access (CDMA) systems in Nakagami multipath fading channel 中川多径衰落信道下码分多址(CDMA)系统的性能

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929215

S. Elnoubi, A. Hashem

引用次数: 2

DCT and DWT feature extraction and ANN classification based technique for non-destructive testing of materials 基于DCT和DWT特征提取和人工神经网络分类的材料无损检测技术

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929156

F. Zaki, M. Abd Elnaby, I. Elshafiey, A. Ashour

引用次数: 6

Fixed channel allocation handover strategies in LEO satellite systems 低轨道卫星系统中固定信道分配切换策略

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929400

M. Riad, M. Elsokkary

引用次数: 4

Efficient satellite orbit determination algorithm 高效的卫星定轨算法

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929219

M. El-Mahy

引用次数: 3

Analysis of electromagnetic absorption in the human head for mobile telephone using the method of moments (MoM) and generalized multipole technique (GMT) 用矩量法(MoM)和广义多极技术(GMT)分析移动电话人体头部电磁吸收

Proceedings of the Eighteenth National Radio Science Conference. NRSC'2001 (IEEE Cat. No.01EX462) Pub Date : 2001-03-27 DOI: 10.1109/NRSC.2001.929423

A. Hassanin

引用次数: 0