IEEE Antennas and Propagation Society International Symposium 1997. Digest最新文献_第10页

Improved linear transmission line model for rectangular, circular and triangular microstrip antennas 改进了矩形、圆形和三角形微带天线的线性传输线模型

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631536

S. Babu, I. Singh, G. Kumar

引用次数: 9

Computation of propagation in adiabatically tapered dielectric structures based on eigenfunction expansions: application to (active) optical devices 基于本征函数展开的绝热锥形介电结构中的传播计算:在有源光学器件中的应用

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631573

F. Causa, J. Sarma, M. Milani

{"title":"Computation of propagation in adiabatically tapered dielectric structures based on eigenfunction expansions: application to (active) optical devices","authors":"F. Causa, J. Sarma, M. Milani","doi":"10.1109/APS.1997.631573","DOIUrl":"https://doi.org/10.1109/APS.1997.631573","url":null,"abstract":"An eigenfunction expansion method is presented which uses the complete set of Hermite-Gauss (HG) functions to obtain the required solution of the propagation problems and has certain advantages, as discussed. This method may also be considered as a perturbation method of analysis since the HG functions are the solutions of a longitudinally uniform waveguide with a parabolically varying transverse refractive index distribution. Note that the HG functions form a complete and discrete set for the function space of interest namely that corresponding to square integrable functions. As a proof of its effectiveness the HG function expansion method is applied to analyse the fields in a variety of longitudinally non-uniform passive devices. The extension of this approach to the to the analysis of active optical devices requires a self-consistent solution to be determined to take into account both the non-uniform device geometry and the non-linear interaction of the optical field with the inversion population distribution in the device. Further, compactness of the analysis scheme for the overall model is achieved by demonstrating that the HG method is also very effective in solving the carrier diffusion equation. In addition, the merits of the collocation numerical procedure have been utilised to reduce the complexity of the formalism.","PeriodicalId":283897,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1997. Digest","volume":"180 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121410375","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: 3

Using periodicity to control spectral characteristics of an array of narrow slots 利用周期性控制窄槽阵列的频谱特性

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.625448

J. A. Reed, D. Byrne

{"title":"Using periodicity to control spectral characteristics of an array of narrow slots","authors":"J. A. Reed, D. Byrne","doi":"10.1109/APS.1997.625448","DOIUrl":"https://doi.org/10.1109/APS.1997.625448","url":null,"abstract":"We consider a frequency selective surface (FSS) consisting of a thin perfectly conducting sheet periodically perforated with narrow slot apertures. For wavelengths greater than the periodicity, such a surface performs similarly to a bandpass filter since the periodic elements within the FSS possess resonance characteristics. The effects on the spectral characteristics of varying the periodicity of a narrow slot array (or its complementary dipole array) was studied by Ott et al. (1967) and Munk et al. (1971). By changing the periodicity, they found it possible to change the location of the resonant wavelength and the bandpass width of the transmission/reflection spectrum. With advances in computational technology, we are able to study these effects of periodicity in narrow slot arrays in much more detail. In this study we used the methods described by Chen (1970) to predict the spectral characteristics of narrow slot arrays designed for use in the middle infrared spectral region. An algorithm was written in FORTRAN for use on either a PC or workstation. Although our work presented is limited to a normally incident plane wave, the approach can be extended to the case of oblique incidence.","PeriodicalId":283897,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1997. Digest","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126052830","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: 5

Numerical method of calculation propagation electromagnetic wave in random discrete media 随机离散介质中电磁波传播的数值计算方法

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.630215

V. Spitsyn

引用次数: 6

Propagation within fractal composite systems with strong permittivity fluctuations 具有强介电常数波动的分形复合系统内的传播

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.625526

W. Merrill, N. Alexopoulos

{"title":"Propagation within fractal composite systems with strong permittivity fluctuations","authors":"W. Merrill, N. Alexopoulos","doi":"10.1109/APS.1997.625526","DOIUrl":"https://doi.org/10.1109/APS.1997.625526","url":null,"abstract":"In random complex composite systems such as a forest environment or a composite mixture, at volume fractions or biomass levels near the percolation threshold fractal or self similar behavior will be seen over a large scale. To describe the propagation of an electromagnetic wave through these systems an extension of the treatment of Tsang and Kong (1981) of the average field in an infinite, random medium, with strong permittivity fluctuations is considered, with scattering clusters whose correlation function is fractal from a minimum inclusion size a/sub 0/ up to a much larger scale. The case investigated is of a spherical minimum inclusion size, with radius a/sub 0/, above the scale of which there is an isotropic fractal fluctuation of the clusters' correlation function, with a maximum cluster size, still much smaller than the electromagnetic wavelength so that the bilocal approximation as described in Tsang and Kong can be used. The system is considered as an isotropic mixture in order to represent a completely random distribution in which no favorable orientations are present in the system. An effective permittivity is presented from this fractal correlation function which is an extension of the Bruggerman effective medium theory to include the scattering size effects of the fractal clusters within a random, composite system.","PeriodicalId":283897,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1997. Digest","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114081388","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

Effective electromagnetic material properties for alternating wedges and hollow pyramidal absorbers 楔形和空心锥体吸收体的有效电磁材料特性

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.625427

C. Holloway, M. Johansson

引用次数: 7

Design of a feed-reflector configuration to optimize performance in the presence of large central blockage 设计了一个馈电反射器配置，以优化存在较大中心阻塞时的性能

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631854

L. Oliver, D. Gonzalez, S. Rengarajan

{"title":"Design of a feed-reflector configuration to optimize performance in the presence of large central blockage","authors":"L. Oliver, D. Gonzalez, S. Rengarajan","doi":"10.1109/APS.1997.631854","DOIUrl":"https://doi.org/10.1109/APS.1997.631854","url":null,"abstract":"In the case of an existing antenna system, an additional antenna may be required for an auxilliary application. Once a primary system has been designed and developed, available area is at a premium, for applications such as on a spacecraft. Commonly, auxilliary antenna systems would not be considered due to large blockage resulting from existing hardware. It is preferred that the blockage be kept to a minimum in order to minimize the deleterious effects on the gain and sidelobe level of the antenna. Normally, the size and blockage of the auxilliary system are constrained by the parameters of the primary system and are not variable. In a typical reflector antenna configuration, the feed illuminates the reflector with a given edge taper. This type of reflector illumination results in the majority of the energy in the central region, where the blockage effects are the greatest. In the case where large central blockage is unavoidable it would be desirable to have a feed illumination pattern that maximizes illumination in the outer periphery of the reflector and minimizes that in the central region; i.e. a doughnut or toroidal shaped pattern is required. The authors show sample current distributions on reflectors illuminated with helices operating in the first and second modes. They compare the calculated gain losses for reflectors with first and second mode helix feeds against increasing central blockage. This data shows that the illumination efficiency is comparable for both cases, but as blockage is increased, the gain loss is decreased when a second mode helix feed is used.","PeriodicalId":283897,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1997. Digest","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116092177","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

Conformal microstrip antennas arrays: a fast analysis for conical arrays 共形微带天线阵列:圆锥阵列的快速分析

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631463

E. Cambiaggio, J. Damiano, D. Augustin, R. Staraj

引用次数: 4

Dual-band dual-polarized microstrip antennas for SAR applications 用于SAR应用的双频双极化微带天线

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631634

L. Shafai, W. Chamma, G. Séguin, N. Sultan

引用次数: 18

The Lunar Prospector helix antenna 月球勘探者螺旋天线

IEEE Antennas and Propagation Society International Symposium 1997. Digest Pub Date : 1997-07-13 DOI: 10.1109/APS.1997.631596

J. Loane, D. Tanner

引用次数: 0