A new method intended for use with digital beamforming array control is presented. It consists of replacing the signals from failed array elements using reconstructed signals from other elements in the array. The method can be applied in the presence of a multiplicity of external noise or jamming signals to provide low sidelobe control for each signal. It involves only linear processing that must be performed at a rate compatible with the information bandwidth. The procedure can improve sidelobe against interfering signals at the expense of reduced signal-to-noise ratio compared to an error-free array.<>
{"title":"A phased array error correction scheme","authors":"R. Mailloux","doi":"10.1109/APS.1993.385368","DOIUrl":"https://doi.org/10.1109/APS.1993.385368","url":null,"abstract":"A new method intended for use with digital beamforming array control is presented. It consists of replacing the signals from failed array elements using reconstructed signals from other elements in the array. The method can be applied in the presence of a multiplicity of external noise or jamming signals to provide low sidelobe control for each signal. It involves only linear processing that must be performed at a rate compatible with the information bandwidth. The procedure can improve sidelobe against interfering signals at the expense of reduced signal-to-noise ratio compared to an error-free array.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125575429","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 author describes a resistively loaded triangular dipole design which is only 0.30 wavelengths long, yet exhibits a VSWR (voltage standing wave ratio) of better than 2.0:1 when mounted in front of the backplane. This improvement in VSWR is at the expense of only a 3 dB decrease in element efficiency. The decrease in efficiency can be directly controlled by the value of the resistive loading. The element has been implemented in a printed circuit array fed by tapered line baluns operating over a 4:1 frequency band. Measured input impedance data vs. loading value is presented, as well as the radiation pattern variation over the band.<>
{"title":"A resistively loaded, printed circuit, electrically short dipole element for wideband array applications","authors":"R. Clapp","doi":"10.1109/APS.1993.385303","DOIUrl":"https://doi.org/10.1109/APS.1993.385303","url":null,"abstract":"The author describes a resistively loaded triangular dipole design which is only 0.30 wavelengths long, yet exhibits a VSWR (voltage standing wave ratio) of better than 2.0:1 when mounted in front of the backplane. This improvement in VSWR is at the expense of only a 3 dB decrease in element efficiency. The decrease in efficiency can be directly controlled by the value of the resistive loading. The element has been implemented in a printed circuit array fed by tapered line baluns operating over a 4:1 frequency band. Measured input impedance data vs. loading value is presented, as well as the radiation pattern variation over the band.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126763305","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}
An analysis of the propagation characteristics of coupled channel waveguides diffused in anisotropic substrates is presented. The wave equation is written in terms of the transverse components of the magnetic field and is numerically solved by the finite-difference method in the frequency domain. The result is a conventional eigenvalue problem without the presence of spurious modes due to the implicit inclusion of the divergence of the magnetic field equal to zero. The formulation is developed to consider biaxial anisotropic dielectrics with a varying index of refraction profile in the waveguide cross section.<>
{"title":"Finite-difference method in the frequency domain for the analysis of the coupling between anisotropic channel waveguides","authors":"C. Sobrinho, A.J. Giarola","doi":"10.1109/APS.1993.385134","DOIUrl":"https://doi.org/10.1109/APS.1993.385134","url":null,"abstract":"An analysis of the propagation characteristics of coupled channel waveguides diffused in anisotropic substrates is presented. The wave equation is written in terms of the transverse components of the magnetic field and is numerically solved by the finite-difference method in the frequency domain. The result is a conventional eigenvalue problem without the presence of spurious modes due to the implicit inclusion of the divergence of the magnetic field equal to zero. The formulation is developed to consider biaxial anisotropic dielectrics with a varying index of refraction profile in the waveguide cross section.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126544532","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 method to facilitate the determination of canonical variables of the one-dimensional wave equation in nonhomogeneous media is presented. In order to solve the second-order hyperbolic partial differential equation a transformation from the independent real variables x and y to two canonical variables is used. A method is presented which shows a way of determining a solution when the wave-speed function /spl sigma/(x,y) meets certain requirements on continuity, and the function u(x,y) meets certain integrability requirements. The method depends on finding an integrating factor, f(x,y).<>
{"title":"An integrating factor to find the canonical variables of a class of wave equations","authors":"S. Giles","doi":"10.1109/APS.1993.385374","DOIUrl":"https://doi.org/10.1109/APS.1993.385374","url":null,"abstract":"A method to facilitate the determination of canonical variables of the one-dimensional wave equation in nonhomogeneous media is presented. In order to solve the second-order hyperbolic partial differential equation a transformation from the independent real variables x and y to two canonical variables is used. A method is presented which shows a way of determining a solution when the wave-speed function /spl sigma/(x,y) meets certain requirements on continuity, and the function u(x,y) meets certain integrability requirements. The method depends on finding an integrating factor, f(x,y).<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121607938","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}
An experimental wideband radio link at 15 GHz has been set up on a 17.6 km line-of-sight between Rennes and Laille to measure the variations of the propagation medium characteristics (attenuation and group delay versus frequency) due to meteorological effects. For this, a meteorological system was set up at the receiver station to measure the variations of the meteorological parameters. Consequently, the atmospheric index of refraction is obtained. Particular emphasis is placed on the occurrence of multipath fading in clear air caused by low-level layering in the troposphere.<>
{"title":"An experimental investigation of line-of-sight multipath propagation at 15 GHz over 500 MHz bandwidth","authors":"M. Touati, G. El Zein, J. Citerne","doi":"10.1109/APS.1993.385166","DOIUrl":"https://doi.org/10.1109/APS.1993.385166","url":null,"abstract":"An experimental wideband radio link at 15 GHz has been set up on a 17.6 km line-of-sight between Rennes and Laille to measure the variations of the propagation medium characteristics (attenuation and group delay versus frequency) due to meteorological effects. For this, a meteorological system was set up at the receiver station to measure the variations of the meteorological parameters. Consequently, the atmospheric index of refraction is obtained. Particular emphasis is placed on the occurrence of multipath fading in clear air caused by low-level layering in the troposphere.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122344707","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}
Uniform diffraction coefficients of PO (physical optics) for impedance surfaces are derived, and accuracy is checked. These diffraction coefficients reveal that PO has no polarization conversion at SB/RB geometrical optics boundaries and this fact is numerically checked.<>
{"title":"Uniform diffraction coefficients of physical optics for impedance surfaces","authors":"M. Oodo, T. Murasaki, M. Ando","doi":"10.1109/APS.1993.385535","DOIUrl":"https://doi.org/10.1109/APS.1993.385535","url":null,"abstract":"Uniform diffraction coefficients of PO (physical optics) for impedance surfaces are derived, and accuracy is checked. These diffraction coefficients reveal that PO has no polarization conversion at SB/RB geometrical optics boundaries and this fact is numerically checked.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"258 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120942518","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 loosely wound spiral antenna with a small number of turns and a reflector is investigated numerically. It is shown that the antenna gain and axial ratio depends on the reflector size, spiral rate of growth, and number of turns. In addition, a spiral antenna with a reflector and parasitic loop is proposed to improve the antenna gain and axial ratio. Improvement of the antenna gain is achieved, while keeping the loop radius the same size as the reflector.<>
{"title":"A two-wire Archimedean spiral antenna with a parasitic loop and a reflector","authors":"Y. Kazama, H. Shirotori, T. Suda","doi":"10.1109/APS.1993.385379","DOIUrl":"https://doi.org/10.1109/APS.1993.385379","url":null,"abstract":"A loosely wound spiral antenna with a small number of turns and a reflector is investigated numerically. It is shown that the antenna gain and axial ratio depends on the reflector size, spiral rate of growth, and number of turns. In addition, a spiral antenna with a reflector and parasitic loop is proposed to improve the antenna gain and axial ratio. Improvement of the antenna gain is achieved, while keeping the loop radius the same size as the reflector.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124896080","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 describe an algorithm for solving Maxwell's equations in anisotropic media in the framework of the finite volume - time domain approach using the theory of characteristics. They obtained compact analytical expressions for fluxes at interfaces between two anisotropic media from Riemann invariants. The interface itself can be a plain interface or may consist of a thin penetrable or impenetrable layer of anisotropic dielectric and magnetic properties. A new physical insight into the underlying approximations involving applications of the theory of characteristics in two and three dimensions has also been obtained.<>
{"title":"Characteristics theory and Maxwell's equations in anisotropic media","authors":"E. Bleszynski, M. Bleszynski, W. Hall","doi":"10.1109/APS.1993.385339","DOIUrl":"https://doi.org/10.1109/APS.1993.385339","url":null,"abstract":"The authors describe an algorithm for solving Maxwell's equations in anisotropic media in the framework of the finite volume - time domain approach using the theory of characteristics. They obtained compact analytical expressions for fluxes at interfaces between two anisotropic media from Riemann invariants. The interface itself can be a plain interface or may consist of a thin penetrable or impenetrable layer of anisotropic dielectric and magnetic properties. A new physical insight into the underlying approximations involving applications of the theory of characteristics in two and three dimensions has also been obtained.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124954828","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}
An algorithm for the computation of the electric field at arbitrary distances from an antenna is discussed and evaluated. The algorithm, which is based on a method for evaluating integrals with rapidly oscillating integrands, is applied to a patch antenna array mounted on a conducting cylinder. The numerical results compare favorably with direct measurements, and insight is gained into the near-field behavior of the patch antenna array.<>
{"title":"Near-zone electric fields of a patch antenna array","authors":"C. du Toit, M. du Plessis, J. Cloete","doi":"10.1109/APS.1993.385553","DOIUrl":"https://doi.org/10.1109/APS.1993.385553","url":null,"abstract":"An algorithm for the computation of the electric field at arbitrary distances from an antenna is discussed and evaluated. The algorithm, which is based on a method for evaluating integrals with rapidly oscillating integrands, is applied to a patch antenna array mounted on a conducting cylinder. The numerical results compare favorably with direct measurements, and insight is gained into the near-field behavior of the patch antenna array.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125186725","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 design and performance of a dual-screen FSS (frequency selective surface) with double-ring elements are demonstrated. Representative transmission data of this FSS are presented. In addition, the hybrid GO-PO (geometrical optics/physical optics) approach is employed to assess a dual reflector antenna with this FSS subreflector. Representative computed far-field patterns with and without the FSS are given for frequencies of 2.3, 8.4, 13.8, and 32 GHz. As expected, the sidelobe and cross-polarization levels are higher with the presence of the FSS. The peak gain is reduced with the FSS.<>
{"title":"Evaluation of multi-band reflector antennas with frequency selective subreflectors","authors":"T. Wu, S. Lee","doi":"10.1109/APS.1993.385354","DOIUrl":"https://doi.org/10.1109/APS.1993.385354","url":null,"abstract":"The design and performance of a dual-screen FSS (frequency selective surface) with double-ring elements are demonstrated. Representative transmission data of this FSS are presented. In addition, the hybrid GO-PO (geometrical optics/physical optics) approach is employed to assess a dual reflector antenna with this FSS subreflector. Representative computed far-field patterns with and without the FSS are given for frequencies of 2.3, 8.4, 13.8, and 32 GHz. As expected, the sidelobe and cross-polarization levels are higher with the presence of the FSS. The peak gain is reduced with the FSS.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125277373","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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