Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730666
J. Daniel, M. Himdi, D. Thouroude
The flexibility of printed technology offers the possibility of innovative radiating structures well suited to various system requirements. Different systems often need specific radiation patterns such as shaped, directive mono or multibeam with prescribed relative level and positions of lobes, or on the contrary omnidirectional radiation in azimuth; both a large bandwidth and directive patterns are more common requirements for communication systems. Research in the University of Rennes I Laboratory has focused on the corner fed square patch and the array design of such elements. Both planar and cylindrical structures have been investigated and some results are reported here. The properties of the corner fed patch are first given and four examples of arrays and applications are presented: dual beam Doppler radar for accurate measurements of speed and shaped beam for radio distribution (Bognais, 1986) (with sector and cosecant square patterns), omnidirectional cylindrical array for search and rescue maritime systems, and large bandwidth planar directive array.
{"title":"Printed antenna arrays: examples of commercial applications","authors":"J. Daniel, M. Himdi, D. Thouroude","doi":"10.1109/APWC.1998.730666","DOIUrl":"https://doi.org/10.1109/APWC.1998.730666","url":null,"abstract":"The flexibility of printed technology offers the possibility of innovative radiating structures well suited to various system requirements. Different systems often need specific radiation patterns such as shaped, directive mono or multibeam with prescribed relative level and positions of lobes, or on the contrary omnidirectional radiation in azimuth; both a large bandwidth and directive patterns are more common requirements for communication systems. Research in the University of Rennes I Laboratory has focused on the corner fed square patch and the array design of such elements. Both planar and cylindrical structures have been investigated and some results are reported here. The properties of the corner fed patch are first given and four examples of arrays and applications are presented: dual beam Doppler radar for accurate measurements of speed and shaped beam for radio distribution (Bognais, 1986) (with sector and cosecant square patterns), omnidirectional cylindrical array for search and rescue maritime systems, and large bandwidth planar directive array.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131744687","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730669
A. Petosa, A. Ittipiboon, M. Cuhaci
This paper features some of the recent advances in dielectric resonator antenna technology at the Communications Research Centre, Ottawa, Canada. Several novel elements are presented offering significant enhancements to parameters such as impedance bandwidth, circular polarization bandwidth, gain, or coupling to feed structures. A variety of linear and planar arrays are also presented to illustrate the performance of these elements in an array environment. Dielectric resonator antenna technology offers a promising alternative to conventional antennas for wireless communication applications.
{"title":"Dielectric resonator antenna technology for wireless applications","authors":"A. Petosa, A. Ittipiboon, M. Cuhaci","doi":"10.1109/APWC.1998.730669","DOIUrl":"https://doi.org/10.1109/APWC.1998.730669","url":null,"abstract":"This paper features some of the recent advances in dielectric resonator antenna technology at the Communications Research Centre, Ottawa, Canada. Several novel elements are presented offering significant enhancements to parameters such as impedance bandwidth, circular polarization bandwidth, gain, or coupling to feed structures. A variety of linear and planar arrays are also presented to illustrate the performance of these elements in an array environment. Dielectric resonator antenna technology offers a promising alternative to conventional antennas for wireless communication applications.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128912812","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730677
M. Solomon
Hand-held GPS receivers have revolutionized navigation for the dismounted soldier. This paper presents the experimental development of a single-element, multimode rectangular microstrip antenna capable of forming a spatial null. Using fundamental and higher order modes within a single microstrip patch radiator, a relatively simple, low-cost adaptive antenna capable of forming a null in the vicinity of the horizon is demonstrated. Numerical and experimental results are presented.
{"title":"Multimode rectangular microstrip antenna for GPS applications","authors":"M. Solomon","doi":"10.1109/APWC.1998.730677","DOIUrl":"https://doi.org/10.1109/APWC.1998.730677","url":null,"abstract":"Hand-held GPS receivers have revolutionized navigation for the dismounted soldier. This paper presents the experimental development of a single-element, multimode rectangular microstrip antenna capable of forming a spatial null. Using fundamental and higher order modes within a single microstrip patch radiator, a relatively simple, low-cost adaptive antenna capable of forming a null in the vicinity of the horizon is demonstrated. Numerical and experimental results are presented.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"53 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113939333","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730646
A.H. El Zooghby, C. Christodoulou, M. Georgiopoulos
Interference rejection is very important and often represents an inexpensive way to increase the system capacity of cellular and mobile communication systems. This paper presents a modification to the radial basis function-based direction finding algorithm where the DOA problem is approached as a mapping which can be modeled by training the network with input output pairs with multiple angular separations. The network is then able to track a fixed number of sources with arbitrary angular separations using a linear array. A novel training technique is suggested and the performance of the RBFNN algorithm is compared to ideal data.
{"title":"Multiple sources neural network direction finding with arbitrary separations","authors":"A.H. El Zooghby, C. Christodoulou, M. Georgiopoulos","doi":"10.1109/APWC.1998.730646","DOIUrl":"https://doi.org/10.1109/APWC.1998.730646","url":null,"abstract":"Interference rejection is very important and often represents an inexpensive way to increase the system capacity of cellular and mobile communication systems. This paper presents a modification to the radial basis function-based direction finding algorithm where the DOA problem is approached as a mapping which can be modeled by training the network with input output pairs with multiple angular separations. The network is then able to track a fixed number of sources with arbitrary angular separations using a linear array. A novel training technique is suggested and the performance of the RBFNN algorithm is compared to ideal data.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134359588","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730661
F. Akleman, L. Sevgi
In this study, the finite-difference time-domain (FDTD) method is used to model mutual effects of a mobile phone and a human head in terms of both biological effects and antenna design. A discrete human head model and a hand-held receiver with various antennas mounted on top of it, are located within a three dimensional (3D) FDTD algorithm is built in Cartesian coordinates. Near fields are simulated directly in the time domain for both sinusoidal and pulse type antenna excitations. The antenna power, input impedance, absorbed power and the specific absorption rate (SAR) distribution inside the head near the hand-held receiver are calculated for various antenna types and human head/hand-held receiver locations. The simulations are carried out for both European GSM and DECT systems (at 900 and 1800 MHz, respectively). The SAR distributions for various vertical and horizontal slices of the head are calculated and are shown to agree with the available calculation and measurement results. Besides, the effects of the human head on the antenna radiation pattern are calculated where far field simulations are obtained via a time-domain near-to-far-field (NTFF) transformation based on Huygen's principle. Various hand-held receiver antennas, including a quarter-wavelength wire, IFA, PIFA, symmetrical and asymmetrical square or rectangular printed loops, are investigated in terms of their radiation pattern, gain and efficiency. Different antenna mountings are used and their effects to both antenna performance and SAR distribution in the head are shown.
{"title":"FDTD analysis of human head-mobile phone interaction in terms of specific absorption rate calculations and antenna design","authors":"F. Akleman, L. Sevgi","doi":"10.1109/APWC.1998.730661","DOIUrl":"https://doi.org/10.1109/APWC.1998.730661","url":null,"abstract":"In this study, the finite-difference time-domain (FDTD) method is used to model mutual effects of a mobile phone and a human head in terms of both biological effects and antenna design. A discrete human head model and a hand-held receiver with various antennas mounted on top of it, are located within a three dimensional (3D) FDTD algorithm is built in Cartesian coordinates. Near fields are simulated directly in the time domain for both sinusoidal and pulse type antenna excitations. The antenna power, input impedance, absorbed power and the specific absorption rate (SAR) distribution inside the head near the hand-held receiver are calculated for various antenna types and human head/hand-held receiver locations. The simulations are carried out for both European GSM and DECT systems (at 900 and 1800 MHz, respectively). The SAR distributions for various vertical and horizontal slices of the head are calculated and are shown to agree with the available calculation and measurement results. Besides, the effects of the human head on the antenna radiation pattern are calculated where far field simulations are obtained via a time-domain near-to-far-field (NTFF) transformation based on Huygen's principle. Various hand-held receiver antennas, including a quarter-wavelength wire, IFA, PIFA, symmetrical and asymmetrical square or rectangular printed loops, are investigated in terms of their radiation pattern, gain and efficiency. Different antenna mountings are used and their effects to both antenna performance and SAR distribution in the head are shown.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122119362","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730667
F. Tefiku
With the continuous growth of commercial communications systems, such as cellular communications systems, the need for low-cost antennas has increased. This paper presents printed strip dipole antennas over plane or shaped reflectors that have acceptable impedance matching and radiation patterns over a frequency range of more than 30 percent. The radiating element used for these antennas represents a series-fed array of two closely spaced printed strip dipoles, which have been shown to have broadband capability. We show that such antennas can be designed to have broadband capabilities when placed above a conducting reflector. To achieve a desired beamwidth, the reflector can be shaped, resulting in an antenna that is well-matched and has acceptable radiation patterns over a wide frequency range. Since constructional simplicity and low manufacturing cost are retained, the antenna is very well-suited to being used as a radiating element in sector zone base stations of cellular communications systems. Design examples of broadband antennas with H-plane half-power beamwidths of 120/spl deg/, 90/spl deg/, and 60/spl deg/, suitable for 3-sector, 4-sector, and 6-sector zone use, respectively, are shown.
{"title":"Broadband sector zone base station antennas","authors":"F. Tefiku","doi":"10.1109/APWC.1998.730667","DOIUrl":"https://doi.org/10.1109/APWC.1998.730667","url":null,"abstract":"With the continuous growth of commercial communications systems, such as cellular communications systems, the need for low-cost antennas has increased. This paper presents printed strip dipole antennas over plane or shaped reflectors that have acceptable impedance matching and radiation patterns over a frequency range of more than 30 percent. The radiating element used for these antennas represents a series-fed array of two closely spaced printed strip dipoles, which have been shown to have broadband capability. We show that such antennas can be designed to have broadband capabilities when placed above a conducting reflector. To achieve a desired beamwidth, the reflector can be shaped, resulting in an antenna that is well-matched and has acceptable radiation patterns over a wide frequency range. Since constructional simplicity and low manufacturing cost are retained, the antenna is very well-suited to being used as a radiating element in sector zone base stations of cellular communications systems. Design examples of broadband antennas with H-plane half-power beamwidths of 120/spl deg/, 90/spl deg/, and 60/spl deg/, suitable for 3-sector, 4-sector, and 6-sector zone use, respectively, are shown.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130865915","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730649
K.W. Kim, Y. Rahmat-Samii
It has been widely acknowledged that comprehensive understanding of EM interactions between human and personal communications antennas is essential for modern handheld antenna design. Results using the FDTD method for the spherical head are compared with those using the eigenfunction expansion method. Also, the near- and far-field patterns of a half-wave antenna with the anatomical head are compared with those of the spherical head. We show that the results obtained with the spherical head can provide useful estimates for various antenna design purposes. Finally, we present engineering design data obtained with a six-layered spherical head. We mainly focus on 900 MHz results.
{"title":"EM interactions between handheld antennas and human: anatomical head vs. multi-layered spherical head","authors":"K.W. Kim, Y. Rahmat-Samii","doi":"10.1109/APWC.1998.730649","DOIUrl":"https://doi.org/10.1109/APWC.1998.730649","url":null,"abstract":"It has been widely acknowledged that comprehensive understanding of EM interactions between human and personal communications antennas is essential for modern handheld antenna design. Results using the FDTD method for the spherical head are compared with those using the eigenfunction expansion method. Also, the near- and far-field patterns of a half-wave antenna with the anatomical head are compared with those of the spherical head. We show that the results obtained with the spherical head can provide useful estimates for various antenna design purposes. Finally, we present engineering design data obtained with a six-layered spherical head. We mainly focus on 900 MHz results.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126937725","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730663
C. Trueman, S. Kubina, J. E. Roy, W.R. Lauber
This paper compares the principal plane radiation patterns of a portable radio handset at 850 MHz computed with the finite difference time domain method with measured radiation patterns. The agreement for the handset in isolation is excellent. The computed patterns of the handset operating near a box model of the head are compared with measured patterns with very good agreement. Finally the computed patterns of the handset operating near a sphere model of the head are compared with measured patterns, with very good agreement, but not quite as good as for the box. The paper demonstrate the effect of simple head models on the radiation patterns of a vertical handset, and provides a validation of the FDTD computations.
{"title":"Validation of FDTD handset and head patterns by measurement","authors":"C. Trueman, S. Kubina, J. E. Roy, W.R. Lauber","doi":"10.1109/APWC.1998.730663","DOIUrl":"https://doi.org/10.1109/APWC.1998.730663","url":null,"abstract":"This paper compares the principal plane radiation patterns of a portable radio handset at 850 MHz computed with the finite difference time domain method with measured radiation patterns. The agreement for the handset in isolation is excellent. The computed patterns of the handset operating near a box model of the head are compared with measured patterns with very good agreement. Finally the computed patterns of the handset operating near a sphere model of the head are compared with measured patterns, with very good agreement, but not quite as good as for the box. The paper demonstrate the effect of simple head models on the radiation patterns of a vertical handset, and provides a validation of the FDTD computations.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116023356","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730645
A.H. El Zooghby, C. Christodoulou, M. Georgiopoulos
A smart antenna based on a neural network implementation of the optimum Wiener solution for the problem of adaptive interference nulling using circular arrays is presented. Modem cellular satellite mobile communications systems and GPS systems suffer from different sources of interference which limit system capacity. This paper develops a fast tracking system to constantly track the mobile users, and then adapt the radiation pattern of the antenna to direct multiple narrow beams to desired users and nulls to sources of interference. The computation of the optimum weights is viewed as a mapping problem which can be modeled using a three-layer radial basis function neural network (RBFNN) trained with input/output pairs. The results obtained from this network are in excellent agreement with the Wiener solution. It is found that networks implementing these functions are successful in tracking mobile users as they move across the antenna's field of view.
{"title":"Radial basis function neural network algorithm for adaptive beamforming in cellular communication systems","authors":"A.H. El Zooghby, C. Christodoulou, M. Georgiopoulos","doi":"10.1109/APWC.1998.730645","DOIUrl":"https://doi.org/10.1109/APWC.1998.730645","url":null,"abstract":"A smart antenna based on a neural network implementation of the optimum Wiener solution for the problem of adaptive interference nulling using circular arrays is presented. Modem cellular satellite mobile communications systems and GPS systems suffer from different sources of interference which limit system capacity. This paper develops a fast tracking system to constantly track the mobile users, and then adapt the radiation pattern of the antenna to direct multiple narrow beams to desired users and nulls to sources of interference. The computation of the optimum weights is viewed as a mapping problem which can be modeled using a three-layer radial basis function neural network (RBFNN) trained with input/output pairs. The results obtained from this network are in excellent agreement with the Wiener solution. It is found that networks implementing these functions are successful in tracking mobile users as they move across the antenna's field of view.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115455056","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}
Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730643
T. Ihara, R. Yamaguchi
The next generation of land mobile communication systems must offer high bit data rates for multimedia and high-quality services. Adaptive arrays are considered to be a key technology to satisfy these demands, and applying them to land mobile radio has been investigated extensively. However, those reports mainly focus on structures of adaptive receivers or adaptive algorithms, few reports consider antenna arrays, especially the effect of the pattern of the antenna elements of the array antenna on adaptive array performance. The effects of the antenna element pattern on performance have been reported, but the investigation was of adaptive array characteristics for a TDMA cellular system. Recently, W-CDMA has been investigated extensively as an access technology for the third-generation mobile radio, IMT-2000. Interference environments are so different between the TDMA system and W-CDMA (DS-CDMA) system, that it is unknown whether their study can be applied to W-CDMA adaptive arrays or not. We examine the performance of an adaptive array receiver of a base station for a W-CDMA system by computer simulation from the viewpoint of the element pattern of the array antenna. We then discuss the relationship between 3 dB element beamwidth and service area in satisfying a bit error rate (BER) of <10/sup -3/.
{"title":"Effects of element pattern for adaptive array in W-CDMA mobile radio","authors":"T. Ihara, R. Yamaguchi","doi":"10.1109/APWC.1998.730643","DOIUrl":"https://doi.org/10.1109/APWC.1998.730643","url":null,"abstract":"The next generation of land mobile communication systems must offer high bit data rates for multimedia and high-quality services. Adaptive arrays are considered to be a key technology to satisfy these demands, and applying them to land mobile radio has been investigated extensively. However, those reports mainly focus on structures of adaptive receivers or adaptive algorithms, few reports consider antenna arrays, especially the effect of the pattern of the antenna elements of the array antenna on adaptive array performance. The effects of the antenna element pattern on performance have been reported, but the investigation was of adaptive array characteristics for a TDMA cellular system. Recently, W-CDMA has been investigated extensively as an access technology for the third-generation mobile radio, IMT-2000. Interference environments are so different between the TDMA system and W-CDMA (DS-CDMA) system, that it is unknown whether their study can be applied to W-CDMA adaptive arrays or not. We examine the performance of an adaptive array receiver of a base station for a W-CDMA system by computer simulation from the viewpoint of the element pattern of the array antenna. We then discuss the relationship between 3 dB element beamwidth and service area in satisfying a bit error rate (BER) of <10/sup -3/.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123291771","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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