IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)最新文献
Reconfigurable, active transmit antennas are attractive for a variety of applications in the military and aerospace sector, since they offer antenna pattern flexibility via reconfigurable amplitude/phase control and permit high EIRP-figures with a set of amplifiers operating at fairly low power levels. Such antennas can be realized as direct radiating arrays, single-reflector multi-feed types or array-fed double reflector antennas (magnified arrays) and comprise, in all cases, a radiator section, a set of power amplifiers (PAs) and a low-power BFN. Looking from the systems perspective, one basic need for the handling of such antennas within the systems analysis and design is an antenna model which can be used for a wide variety of antenna types and provides easily usable tools for the prediction of the most relevant system figures. Whereas such a description for the gain and G/T of active receive antennas has been proposed in Kraft and Blaschke (1997), the current contribution provides a corresponding model for the EIRP and power efficiency of active transmit antennas where the antenna gain is almost meaningless.
{"title":"EIRP and power efficiency of reconfigurable active transmit antennas","authors":"U. Kraft","doi":"10.1109/APS.1999.789515","DOIUrl":"https://doi.org/10.1109/APS.1999.789515","url":null,"abstract":"Reconfigurable, active transmit antennas are attractive for a variety of applications in the military and aerospace sector, since they offer antenna pattern flexibility via reconfigurable amplitude/phase control and permit high EIRP-figures with a set of amplifiers operating at fairly low power levels. Such antennas can be realized as direct radiating arrays, single-reflector multi-feed types or array-fed double reflector antennas (magnified arrays) and comprise, in all cases, a radiator section, a set of power amplifiers (PAs) and a low-power BFN. Looking from the systems perspective, one basic need for the handling of such antennas within the systems analysis and design is an antenna model which can be used for a wide variety of antenna types and provides easily usable tools for the prediction of the most relevant system figures. Whereas such a description for the gain and G/T of active receive antennas has been proposed in Kraft and Blaschke (1997), the current contribution provides a corresponding model for the EIRP and power efficiency of active transmit antennas where the antenna gain is almost meaningless.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128318621","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 beam-steering capability of compact antennas presenting transverse resonances could be employed in wireless applications. Adaptive beam-steering arrays can improve communication reliability and energy efficiency. The 2-D method of auxiliary sources is employed to study the performance of a compact size transverse resonant antenna composed of wire radiators embedded in a dielectric substrate and backed by a conductive surface. In this particular case, the antenna is capable of scanning and changing the width of the main lobe of its pattern, as well as reduce the back radiated energy. Attention is paid to energy absorption by the user's body, as well as to EMC issues with body-worn electronic devices.
{"title":"The method of auxiliary sources applied to the analysis of adaptive transverse resonant antennas","authors":"G. Bit‐Babik, K. Tavzarashvili, A. Bijamov","doi":"10.1109/APS.1999.789323","DOIUrl":"https://doi.org/10.1109/APS.1999.789323","url":null,"abstract":"The beam-steering capability of compact antennas presenting transverse resonances could be employed in wireless applications. Adaptive beam-steering arrays can improve communication reliability and energy efficiency. The 2-D method of auxiliary sources is employed to study the performance of a compact size transverse resonant antenna composed of wire radiators embedded in a dielectric substrate and backed by a conductive surface. In this particular case, the antenna is capable of scanning and changing the width of the main lobe of its pattern, as well as reduce the back radiated energy. Attention is paid to energy absorption by the user's body, as well as to EMC issues with body-worn electronic devices.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128424359","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 C-band conformal aperture coupled microstrip patch phased array was modelled and fabricated. The measured results show the capability of the array to form a directive sector beam as well as an omnidirectional pattern within the measured bandwidth of 19%. As the gain variation is negligible while scanning the direction of the array, it is recommended for 360/spl deg/ cover in communication systems.
{"title":"Conformal aperture coupled microstrip phased array on a cylindrical surface","authors":"D. Loffler, W. Wiesbeckl, B. Johannisson","doi":"10.1109/APS.1999.789453","DOIUrl":"https://doi.org/10.1109/APS.1999.789453","url":null,"abstract":"A C-band conformal aperture coupled microstrip patch phased array was modelled and fabricated. The measured results show the capability of the array to form a directive sector beam as well as an omnidirectional pattern within the measured bandwidth of 19%. As the gain variation is negligible while scanning the direction of the array, it is recommended for 360/spl deg/ cover in communication systems.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128162117","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}
In this paper we present the test and validation results for the RCS of spherical objects derived by using conformal finite difference time domain (CFDTD) technique, which was introduced for obviating the staircasing errors introduced by the conventional finite difference time domain (FDTD) approach when dealing with curved bodies. We demonstrate that the CFDTD results show significant improvement in accuracy over those derived by using the conventional FDTD that employs a staircasing of the sphere geometry.
{"title":"Efficient and accurate calculation of radar cross section of curved objects by using the conformal finite difference time domain scheme","authors":"S. Dey, R. Mittra, N. Pegg","doi":"10.1109/APS.1999.789353","DOIUrl":"https://doi.org/10.1109/APS.1999.789353","url":null,"abstract":"In this paper we present the test and validation results for the RCS of spherical objects derived by using conformal finite difference time domain (CFDTD) technique, which was introduced for obviating the staircasing errors introduced by the conventional finite difference time domain (FDTD) approach when dealing with curved bodies. We demonstrate that the CFDTD results show significant improvement in accuracy over those derived by using the conventional FDTD that employs a staircasing of the sphere geometry.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128579838","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}
We examine the MM wave polarimetric response of tree trunks at near grazing incidence. A tree trunk possesses a strong MM wave backscatter response, in part, due to its substantial vertical extent above ground. Although, several scattering mechanisms contribute to the the backscatter response of a tree trunk above ground, only the direct backscatter component of the trunk is considered. A geometric-optics model for predicting the MM wave backscatter response of tree trunks and rough dielectric cylinders is proposed first, then compared to the measurements performed at 95 GHz.
{"title":"Modeling the backscattering response of tree trunks at MMW frequencies","authors":"A. El-Rouby, F. Ulaby, A. Nashashibi","doi":"10.1109/APS.1999.789073","DOIUrl":"https://doi.org/10.1109/APS.1999.789073","url":null,"abstract":"We examine the MM wave polarimetric response of tree trunks at near grazing incidence. A tree trunk possesses a strong MM wave backscatter response, in part, due to its substantial vertical extent above ground. Although, several scattering mechanisms contribute to the the backscatter response of a tree trunk above ground, only the direct backscatter component of the trunk is considered. A geometric-optics model for predicting the MM wave backscatter response of tree trunks and rough dielectric cylinders is proposed first, then compared to the measurements performed at 95 GHz.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129329130","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}
This paper focuses on a new concept in diplexer design, namely a combination of the standard mode-matching technique (MMT) with the coupled-integral-equations technique (CIET), the latter being used only for the synthesis and analysis of the individual channel filters. Several major advantages are associated with this approach. First, for a full-cycle analysis of a diplexer configuration, the combined method reduces the CPU time significantly compared to ordinary MMT. Secondly, the number of basis functions in the CIET can be reduced during optimization without a shift in frequency as matrix sizes do not depend on the number of modes. In standard MMT algorithms, a reduced number of modes is usually associated with a (sometimes remarkable) shift towards lower frequencies. Thirdly, the CIET-at almost no additional computational cost-allows the extraction of the generalized scattering matrix so that the results are easily interfaced with mode-matching calculations of other components.
{"title":"A combined mode-matching and coupled-integral-equations technique for the design of narrow-band H-plane waveguide diplexers","authors":"J. Bornemann, A. Amari, R. Vahldieck","doi":"10.1109/APS.1999.789469","DOIUrl":"https://doi.org/10.1109/APS.1999.789469","url":null,"abstract":"This paper focuses on a new concept in diplexer design, namely a combination of the standard mode-matching technique (MMT) with the coupled-integral-equations technique (CIET), the latter being used only for the synthesis and analysis of the individual channel filters. Several major advantages are associated with this approach. First, for a full-cycle analysis of a diplexer configuration, the combined method reduces the CPU time significantly compared to ordinary MMT. Secondly, the number of basis functions in the CIET can be reduced during optimization without a shift in frequency as matrix sizes do not depend on the number of modes. In standard MMT algorithms, a reduced number of modes is usually associated with a (sometimes remarkable) shift towards lower frequencies. Thirdly, the CIET-at almost no additional computational cost-allows the extraction of the generalized scattering matrix so that the results are easily interfaced with mode-matching calculations of other components.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129360031","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 electrically short thin-wire antenna oriented normal to a conducting surface is often used to measure the normal electric field or charge density at the surface. Calibration of the so-called charge probe is relatively simple if there are no nearby objects which can "load" the probe and alter its response. A probe on a surface near a dielectric or conducting interface is a case of practical interest in which probe loading must be accounted for if accurate measurements are expected. The main purposes of this paper are to lay the groundwork for an understanding of probe loading and to suggest a simple method for accounting for the effects of loading as the charge probe becomes arbitrarily close to the interface. We present a simple and accurate method for determining the current in a short wire very near to an interface. Data computed from a method employing Sommerfeld integrals and the proposed approximate method are compared.
{"title":"Analysis of a charge probe and its response near metallic and dielectric interface","authors":"C. Ozzaim, C. Butler","doi":"10.1109/APS.1999.788277","DOIUrl":"https://doi.org/10.1109/APS.1999.788277","url":null,"abstract":"An electrically short thin-wire antenna oriented normal to a conducting surface is often used to measure the normal electric field or charge density at the surface. Calibration of the so-called charge probe is relatively simple if there are no nearby objects which can \"load\" the probe and alter its response. A probe on a surface near a dielectric or conducting interface is a case of practical interest in which probe loading must be accounted for if accurate measurements are expected. The main purposes of this paper are to lay the groundwork for an understanding of probe loading and to suggest a simple method for accounting for the effects of loading as the charge probe becomes arbitrarily close to the interface. We present a simple and accurate method for determining the current in a short wire very near to an interface. Data computed from a method employing Sommerfeld integrals and the proposed approximate method are compared.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"313 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129377771","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 dual band 36 element bowtie grid oscillator has been demonstrated. The bowtie structure provides the design flexibility to achieve the dual frequency band operation and may allow the optimum load impedance to be presented to the transistor for maximum DC-to-RF conversion efficiency. When the grid drain-source bias voltage is 2 V and the total drain current for the grid is 110 mA, the oscillator operated at 21.3 GHz and 29.7 GHz. The output power at 21.3 GHz is 45 mW and the directivity is 13.8 dB. The DC-to-RF conversion efficiency is 20.5% at 21 GHz. The output power at 29.7 GHz is 2 mW and the directivity is 21.8 dB. DC-to-RF conversion efficiency is less than 1%.
{"title":"Millimeter-wave dual band bowtie oscillator array","authors":"Liang Quan Sun, R. Weikle, A. Zaghloul","doi":"10.1109/APS.1999.789291","DOIUrl":"https://doi.org/10.1109/APS.1999.789291","url":null,"abstract":"A dual band 36 element bowtie grid oscillator has been demonstrated. The bowtie structure provides the design flexibility to achieve the dual frequency band operation and may allow the optimum load impedance to be presented to the transistor for maximum DC-to-RF conversion efficiency. When the grid drain-source bias voltage is 2 V and the total drain current for the grid is 110 mA, the oscillator operated at 21.3 GHz and 29.7 GHz. The output power at 21.3 GHz is 45 mW and the directivity is 13.8 dB. The DC-to-RF conversion efficiency is 20.5% at 21 GHz. The output power at 29.7 GHz is 2 mW and the directivity is 21.8 dB. DC-to-RF conversion efficiency is less than 1%.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127533410","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 asymptotic theory for inhomogeneous waves is based on the first order Luneberg-Kline expansion of the electromagnetic fields, which is also valid when the phase function is complex. This paper summarizes the propagation and transport energy trajectories for inhomogeneous cylindrical waves, which follows from the complex beam approximation under a complex radiation condition, and behave as inhomogeneous local plane waves. They are a particular case of inhomogeneous waves characterized by a pseudo-Gaussian profile in the transverse beam axis direction. In the high-frequency regime, a new approximation of this kind of solutions is made and simpler expressions are found together with its validity range.
{"title":"Inhomogeneous cylindrical waves: an approach to complex beams","authors":"M.J. Gonzalez Morales, E. Gago-Ribas","doi":"10.1109/APS.1999.789575","DOIUrl":"https://doi.org/10.1109/APS.1999.789575","url":null,"abstract":"The asymptotic theory for inhomogeneous waves is based on the first order Luneberg-Kline expansion of the electromagnetic fields, which is also valid when the phase function is complex. This paper summarizes the propagation and transport energy trajectories for inhomogeneous cylindrical waves, which follows from the complex beam approximation under a complex radiation condition, and behave as inhomogeneous local plane waves. They are a particular case of inhomogeneous waves characterized by a pseudo-Gaussian profile in the transverse beam axis direction. In the high-frequency regime, a new approximation of this kind of solutions is made and simpler expressions are found together with its validity range.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127171279","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}
C. Kyriazidou, H. Contopanagos, W. Merrill, N. Alexopoulos
Composite periodic structures, also named photonic band gap (PBG) materials, have attracted a lot of attention due to their controllable dispersive properties that allow a wide range of applications in novel antenna structures and frequency selective surfaces. Up to now, the analysis of PBG structures has been performed by numerical methods. Therefore optimizing the performance of a particular PBG design usually requires a case-by-case, trial and error method which is both CPU-time consuming and physically obscure. In order to bypass these limitations and isolate the response of the medium from the device in use, an effective description for PBG crystals is needed far beyond the quasistatic limit of traditional effective medium theories. Such an effective description for a metalo-dielectric photonic band gap (PBG) material with disk inclusions has been developed analytically. In this paper, we generalize this approach by presenting the effective permittivity and permeability functions for inclusions of a general canonical shape. This is useful in optimising the band gap formation as a function of the shape of the implants. We focus on flat inclusions of infinitesimal thickness that create thin planar geometries which are relevant for microwave devices.
{"title":"Effective permittivity and permeability functions of metalo-dielectric photonic band gap materials","authors":"C. Kyriazidou, H. Contopanagos, W. Merrill, N. Alexopoulos","doi":"10.1109/APS.1999.788331","DOIUrl":"https://doi.org/10.1109/APS.1999.788331","url":null,"abstract":"Composite periodic structures, also named photonic band gap (PBG) materials, have attracted a lot of attention due to their controllable dispersive properties that allow a wide range of applications in novel antenna structures and frequency selective surfaces. Up to now, the analysis of PBG structures has been performed by numerical methods. Therefore optimizing the performance of a particular PBG design usually requires a case-by-case, trial and error method which is both CPU-time consuming and physically obscure. In order to bypass these limitations and isolate the response of the medium from the device in use, an effective description for PBG crystals is needed far beyond the quasistatic limit of traditional effective medium theories. Such an effective description for a metalo-dielectric photonic band gap (PBG) material with disk inclusions has been developed analytically. In this paper, we generalize this approach by presenting the effective permittivity and permeability functions for inclusions of a general canonical shape. This is useful in optimising the band gap formation as a function of the shape of the implants. We focus on flat inclusions of infinitesimal thickness that create thin planar geometries which are relevant for microwave devices.","PeriodicalId":391546,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127231166","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}
IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)
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