Summary form only given. Double-scatter phenomena were illustrated by examining the types of tracks which result from forming ISAR (inverse-synthetic aperture radar) images of targets with strong multiple scattering. One-dimensional images were illustrated, for which the tracks consist of varying range versus angle. Two-dimensional images were then illustrated, for which the tracks consist of varying range and cross-range versus angle. 2-D image tracks were simplified by introducing a relatively unusual target-based coordinate system. Normally, 2-D images are displayed with the downrange axis fixed vertically on the page. As the aspect angle changes, the target effectively rotates by the negative of the aspect angle. This gives the viewer a fixed-radar perspective-the radar is always at the bottom of the page, pointing up toward the rotating targets. An alternative imaging method gives the viewer a fixed-target perspective-the target remains stationary while the radar revolves around it.<>
{"title":"Double-scatter tracks in 1D and 2D images","authors":"R. Ueberschaer","doi":"10.1109/APS.1992.221524","DOIUrl":"https://doi.org/10.1109/APS.1992.221524","url":null,"abstract":"Summary form only given. Double-scatter phenomena were illustrated by examining the types of tracks which result from forming ISAR (inverse-synthetic aperture radar) images of targets with strong multiple scattering. One-dimensional images were illustrated, for which the tracks consist of varying range versus angle. Two-dimensional images were then illustrated, for which the tracks consist of varying range and cross-range versus angle. 2-D image tracks were simplified by introducing a relatively unusual target-based coordinate system. Normally, 2-D images are displayed with the downrange axis fixed vertically on the page. As the aspect angle changes, the target effectively rotates by the negative of the aspect angle. This gives the viewer a fixed-radar perspective-the radar is always at the bottom of the page, pointing up toward the rotating targets. An alternative imaging method gives the viewer a fixed-target perspective-the target remains stationary while the radar revolves around it.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130146882","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}
The use of the anisotropic reactive reflector is to eliminate cross-polarization is considered for the following two cases: a parabolic antenna fed by a dipole; and a parabolic antenna fed by a source radiating symmetrical E/sub 01/ or H/sub 01/ circular waveguide modes. The reflector surface impedance properties and design features typical for feed examples are discussed.<>
{"title":"Synthesis and properties of the surface impedance in the parabolic reflector antennas with low cross-polarization","authors":"M. Winebrand","doi":"10.1109/APS.1992.221920","DOIUrl":"https://doi.org/10.1109/APS.1992.221920","url":null,"abstract":"The use of the anisotropic reactive reflector is to eliminate cross-polarization is considered for the following two cases: a parabolic antenna fed by a dipole; and a parabolic antenna fed by a source radiating symmetrical E/sub 01/ or H/sub 01/ circular waveguide modes. The reflector surface impedance properties and design features typical for feed examples are discussed.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"46 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134128451","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}
S. Bharj, R. Camisa, S. Grober, F. Wozniak, E. Pendleton
A highly efficient rectenna array at 5.87 GHz, comprising 1000 dipole elements, has been designed, developed, and demonstrated for microwave powered applications. The rectenna dipole elements exhibit an RF to DC efficiency exceeding 80% with a uniform illuminated aperture. The rectification element consists of a custom packaged silicon Schottky diode quad bridge with a high reverse breakdown voltage. The novel mechanical structure of the low-cost rectenna consists of a dipole array substrate and a busbar substrate suitably assembled to ensure diode cooling through conduction and convection. Power densities of 100 mW/cm/sup 2/ could be handled to produce DC power well in excess of 450 W at a frequency of 5.86 GHz.<>
{"title":"High efficiency C-band 1000 element rectenna array for microwave powered applications","authors":"S. Bharj, R. Camisa, S. Grober, F. Wozniak, E. Pendleton","doi":"10.1109/APS.1992.221986","DOIUrl":"https://doi.org/10.1109/APS.1992.221986","url":null,"abstract":"A highly efficient rectenna array at 5.87 GHz, comprising 1000 dipole elements, has been designed, developed, and demonstrated for microwave powered applications. The rectenna dipole elements exhibit an RF to DC efficiency exceeding 80% with a uniform illuminated aperture. The rectification element consists of a custom packaged silicon Schottky diode quad bridge with a high reverse breakdown voltage. The novel mechanical structure of the low-cost rectenna consists of a dipole array substrate and a busbar substrate suitably assembled to ensure diode cooling through conduction and convection. Power densities of 100 mW/cm/sup 2/ could be handled to produce DC power well in excess of 450 W at a frequency of 5.86 GHz.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134434711","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}
The authors present a model for the dual-feed nearly square patch antenna which accounts for the loading effects of the output port upon the antenna. Theory indicates that the required antenna dimensions depend on the load impedance seen by the antenna. It is also seen that the axial ratio bandwidth of the antenna can be varied by correct choice of load impedance. Typical results of antennas designed to operate at 2.450 GHz indicate a broadening of the 3 dB axial ratio bandwidth from approximately 19 MHz with a load impedance of R/sub L/=1.0 M Omega to a value in excess of 130 MHz for R/sub L/=50 Omega .<>
本文建立了考虑输出端对天线载荷影响的双馈近方贴片天线模型。理论表明，所需的天线尺寸取决于天线所看到的负载阻抗。通过正确选择负载阻抗，可以改变天线的轴比带宽。设计工作在2.450 GHz的天线的典型结果表明，负载阻抗为R/sub /=1.0 M ω时，3db轴比带宽从约19 MHz扩展到R/sub /=50 ω .>时的130 MHz以上
{"title":"Effects of load impedance on the dimensions and beamwidth of a dual feed nearly square patch antenna for circular polarisations","authors":"D. Smith, R. Livingston, R. Jefferson","doi":"10.1109/APS.1992.221625","DOIUrl":"https://doi.org/10.1109/APS.1992.221625","url":null,"abstract":"The authors present a model for the dual-feed nearly square patch antenna which accounts for the loading effects of the output port upon the antenna. Theory indicates that the required antenna dimensions depend on the load impedance seen by the antenna. It is also seen that the axial ratio bandwidth of the antenna can be varied by correct choice of load impedance. Typical results of antennas designed to operate at 2.450 GHz indicate a broadening of the 3 dB axial ratio bandwidth from approximately 19 MHz with a load impedance of R/sub L/=1.0 M Omega to a value in excess of 130 MHz for R/sub L/=50 Omega .<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"234 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133938819","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}
A novel polarimetric wave propagation model was introduced by M. Lebherz et al. (IEEE Trans. on Antennas Prop., vol.40, no.2, 1992). The model requires a digital terrain data bank and considers multipath propagation. An application of this model to polarimetric investigations of terrestrial radio links in the VHF/UHF frequency range is presented. Based on the UTD and physical optics (PO), an approach is described for calculating the propagation effects in natural 3D terrain, given by topological and morphological data. The influence of real terrain on the polarimetric propagation properties is considered, and typical polarization signatures of multipath propagation are presented. Based on the derived polarimetric signatures, investigations of optimum polarization states for minimum polarization loss and clutter suppression can be performed.<>
M. Lebherz等人提出了一种新的极化波传播模型。关于天线道具。第40卷，没有。2, 1992)。该模型需要一个数字地形数据库，并考虑了多径传播。介绍了该模型在VHF/UHF频段地面无线电链路极化测量中的应用。基于UTD和物理光学(PO)，提出了一种基于拓扑和形态数据的自然三维地形传播效应计算方法。考虑了实际地形对偏振传播特性的影响，给出了典型的多径传播偏振特征。基于导出的极化特征，可以研究最小极化损耗和杂波抑制的最佳极化状态
{"title":"Features of polarimetric terrestrial wave propagation","authors":"D. Cichon, T. Kurner, W. Wiesbeck","doi":"10.1109/APS.1992.221674","DOIUrl":"https://doi.org/10.1109/APS.1992.221674","url":null,"abstract":"A novel polarimetric wave propagation model was introduced by M. Lebherz et al. (IEEE Trans. on Antennas Prop., vol.40, no.2, 1992). The model requires a digital terrain data bank and considers multipath propagation. An application of this model to polarimetric investigations of terrestrial radio links in the VHF/UHF frequency range is presented. Based on the UTD and physical optics (PO), an approach is described for calculating the propagation effects in natural 3D terrain, given by topological and morphological data. The influence of real terrain on the polarimetric propagation properties is considered, and typical polarization signatures of multipath propagation are presented. Based on the derived polarimetric signatures, investigations of optimum polarization states for minimum polarization loss and clutter suppression can be performed.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131749291","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}
Summary form only given. Planar antennas are photoconductively switched to generate and coherently detect ultrawideband (UWB), transient radiation. This radiation has a bandwidth from 5 to 70 GHz. The antennas are switched photoconductively using a 76-MHz train of 5-ps-duration, 527-nm-wavelength optical pulses generated from a frequency-doubled pulse-compressed mode-locked Nd-YLF laser. The UWB microwave and millimeter-wave radiation generated by these antennas is used to perform UWB transient scattering measurements from resonant targets. Prototype UWB time-domain scattering measurements have been performed using a unique table-top scattering facility. The experimental results are compared with theory. Particular attention is given to the late-time response of targets using such a system.<>
{"title":"Ultra-wideband scattering from resonant structures using optoelectronically switched antennas","authors":"K. Agi, L. Carin","doi":"10.1109/APS.1992.221419","DOIUrl":"https://doi.org/10.1109/APS.1992.221419","url":null,"abstract":"Summary form only given. Planar antennas are photoconductively switched to generate and coherently detect ultrawideband (UWB), transient radiation. This radiation has a bandwidth from 5 to 70 GHz. The antennas are switched photoconductively using a 76-MHz train of 5-ps-duration, 527-nm-wavelength optical pulses generated from a frequency-doubled pulse-compressed mode-locked Nd-YLF laser. The UWB microwave and millimeter-wave radiation generated by these antennas is used to perform UWB transient scattering measurements from resonant targets. Prototype UWB time-domain scattering measurements have been performed using a unique table-top scattering facility. The experimental results are compared with theory. Particular attention is given to the late-time response of targets using such a system.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131815372","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}
The authors study magnetostatic wave propagation (MSW) in multilayered magnetic structure (YIG/GGG/YIG/GGG), in which the static magnetizations in the two magnetic layers are not colinear. It is assumed that there exists an arbitrary angle alpha between the two magnetizations for a given applied DC field. Therefore, the effect of the relative orientation between the two magnetizations in two different YIG layers on the dispersion and time delay can be explored. The misalignment alpha is determined by the applied DC field, the static magnetizations, and the uniaxial anisotropy fields. The general dispersion relation is strongly affected by alpha . It is this misalignment that leads to surface mode propagation in one layer and forward volume mode propagation in the other layer. One may control the applied DC field to vary alpha to obtain the desired nondispersive time delay for microwave signal processing.<>
{"title":"Magnetostatic wave propagation in a multilayered magnetic structure with an arbitrary orientation between the static magnetizations","authors":"K. Sun, S. Bolls","doi":"10.1109/APS.1992.221671","DOIUrl":"https://doi.org/10.1109/APS.1992.221671","url":null,"abstract":"The authors study magnetostatic wave propagation (MSW) in multilayered magnetic structure (YIG/GGG/YIG/GGG), in which the static magnetizations in the two magnetic layers are not colinear. It is assumed that there exists an arbitrary angle alpha between the two magnetizations for a given applied DC field. Therefore, the effect of the relative orientation between the two magnetizations in two different YIG layers on the dispersion and time delay can be explored. The misalignment alpha is determined by the applied DC field, the static magnetizations, and the uniaxial anisotropy fields. The general dispersion relation is strongly affected by alpha . It is this misalignment that leads to surface mode propagation in one layer and forward volume mode propagation in the other layer. One may control the applied DC field to vary alpha to obtain the desired nondispersive time delay for microwave signal processing.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130902789","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}
It is shown that, as an alternative to using cable randomization, decorrelation can be obtained by randomizing the element phase settings at one half of the LSB value. As demonstrated in computer simulations for both methods, this randomization is not only more accurate than cable randomization; it can also be obtained cost-free in most modern phased arrays. To decorrelate the quantization error using DMC (distributed modular controller) randomization, a random number stored in a DMC register is added to DMC's phase shift calculation. The maximum value of this random number is one-half of the phase shifter LSB. The lower bound for the LSB of this random number is equal to the LSB of the DMC. Therefore, the number of bits in this random number is equal to or less than the difference between the DMC word length and the number of bits in the phase shifter. The choice of randomization bit length is affected by tradeoffs involving DMC cost and throughput and array pointing accuracy. Some of these tradeoffs are summarized for a 16-b DMC.<>
{"title":"Angle accuracy improvement using DMC randomization for phased array","authors":"Kaichiang Chang, F. Beltran","doi":"10.1109/APS.1992.221990","DOIUrl":"https://doi.org/10.1109/APS.1992.221990","url":null,"abstract":"It is shown that, as an alternative to using cable randomization, decorrelation can be obtained by randomizing the element phase settings at one half of the LSB value. As demonstrated in computer simulations for both methods, this randomization is not only more accurate than cable randomization; it can also be obtained cost-free in most modern phased arrays. To decorrelate the quantization error using DMC (distributed modular controller) randomization, a random number stored in a DMC register is added to DMC's phase shift calculation. The maximum value of this random number is one-half of the phase shifter LSB. The lower bound for the LSB of this random number is equal to the LSB of the DMC. Therefore, the number of bits in this random number is equal to or less than the difference between the DMC word length and the number of bits in the phase shifter. The choice of randomization bit length is affected by tradeoffs involving DMC cost and throughput and array pointing accuracy. Some of these tradeoffs are summarized for a 16-b DMC.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130912537","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}
The authors have proposed a waveguide pi -junction with an inductive post for the element of a multiple-way power divider in a single-layer slotted waveguide array, in which a feed waveguide is placed on the same layer in the radiating waveguide. The power dividing characteristics have been analyzed by Galerkin's method and confirmed experimentally. A -6 dB model pi -junction for the 4 GHz band was designed and fabricated. The analysis accurately predicts the power difference between two output waveguides and the reflection which is below -30 dB over a 5.4% bandwidth.<>
{"title":"Waveguide pi -junction with an inductive post","authors":"J. Hirokawa, M. Ando, N. Goto","doi":"10.1109/APS.1992.221445","DOIUrl":"https://doi.org/10.1109/APS.1992.221445","url":null,"abstract":"The authors have proposed a waveguide pi -junction with an inductive post for the element of a multiple-way power divider in a single-layer slotted waveguide array, in which a feed waveguide is placed on the same layer in the radiating waveguide. The power dividing characteristics have been analyzed by Galerkin's method and confirmed experimentally. A -6 dB model pi -junction for the 4 GHz band was designed and fabricated. The analysis accurately predicts the power difference between two output waveguides and the reflection which is below -30 dB over a 5.4% bandwidth.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133327091","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}
The Virginian Tech experiment includes 12-, 20-, and 30-GHz beacon receivers and colocated 20-GHz and 30-GHz small-scale diversity terminals to provide data in which the effects of frequency diversity are combined with the effects of spatial diversity. The results obtained with this array of terminals are useful in studying the structure of small-scale turbulence and also in determining optimal diversity configurations. The effects of spatial diversity are studied, through a cross-correlation analysis. The median value of the correlation coefficient is plotted as a function of vertical spacing and the total spacing between the beams of each pair of terminals. As the spacing (total or vertical) increases, the median cross-correlation coefficient decreases fairly rapidly, and then reaches a region of slower variations where the median correlation is nearly constant, with values that may be negative. As the spacing is further increased the median correlation converges to 0.<>
{"title":"Measurements of cross-correlation between spaced receivers from the Virginia Tech OLYMPUS experiment","authors":"F. Haidara, T. Pratt, C. Bostian","doi":"10.1109/APS.1992.221826","DOIUrl":"https://doi.org/10.1109/APS.1992.221826","url":null,"abstract":"The Virginian Tech experiment includes 12-, 20-, and 30-GHz beacon receivers and colocated 20-GHz and 30-GHz small-scale diversity terminals to provide data in which the effects of frequency diversity are combined with the effects of spatial diversity. The results obtained with this array of terminals are useful in studying the structure of small-scale turbulence and also in determining optimal diversity configurations. The effects of spatial diversity are studied, through a cross-correlation analysis. The median value of the correlation coefficient is plotted as a function of vertical spacing and the total spacing between the beams of each pair of terminals. As the spacing (total or vertical) increases, the median cross-correlation coefficient decreases fairly rapidly, and then reaches a region of slower variations where the median correlation is nearly constant, with values that may be negative. As the spacing is further increased the median correlation converges to 0.<<ETX>>","PeriodicalId":289865,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium 1992 Digest","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133463761","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}
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