Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730683
S. Targonski, D. Pozar, R. Waterhouse
The design advantages provided by aperture-coupled microstrip patches can be very useful in wireless communications applications. A way to improve the front-to-back ratio is to place a microstrip antenna element behind the aperture as a reflector. Proximity coupling between the feed line and the reflecting element is negligible due to the thick foam substrate used, allowing use of the reciprocity method of analysis. Also, the directive patch elements are shielded from the reflector by the ground plane. Therefore, only interactions between the reflector and the aperture need to be modeled, resulting in a simple analysis. For aperture-coupled patch designs with a front-to-back ratio of 10 dB or greater, the introduction of a reflecting element has a negligible effect on the input impedance of the antenna. Therefore, a reflector element can readily be incorporated into existing designs.
{"title":"Aperture-coupled microstrip antennas using reflector elements for wireless communications","authors":"S. Targonski, D. Pozar, R. Waterhouse","doi":"10.1109/APWC.1998.730683","DOIUrl":"https://doi.org/10.1109/APWC.1998.730683","url":null,"abstract":"The design advantages provided by aperture-coupled microstrip patches can be very useful in wireless communications applications. A way to improve the front-to-back ratio is to place a microstrip antenna element behind the aperture as a reflector. Proximity coupling between the feed line and the reflecting element is negligible due to the thick foam substrate used, allowing use of the reciprocity method of analysis. Also, the directive patch elements are shielded from the reflector by the ground plane. Therefore, only interactions between the reflector and the aperture need to be modeled, resulting in a simple analysis. For aperture-coupled patch designs with a front-to-back ratio of 10 dB or greater, the introduction of a reflecting element has a negligible effect on the input impedance of the antenna. Therefore, a reflector element can readily be incorporated into existing designs.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"87 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":"126184704","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.1998.730631
E. Zentner, R. Zentner, J. Bartolić
Dipole antenna performance in a strong multipath environment due to multiple reflections is discussed. A method of computing the field distribution inside a room of arbitrary dimensions and electric characteristics of the walls is proposed. Measurements for different transmitter-receiver configurations and polarizations are presented. Based on computer simulation and measurement results some conclusions are made.
{"title":"An analysis of radio signal level variations in strong multipath indoor environment","authors":"E. Zentner, R. Zentner, J. Bartolić","doi":"10.1109/APWC.1998.730631","DOIUrl":"https://doi.org/10.1109/APWC.1998.730631","url":null,"abstract":"Dipole antenna performance in a strong multipath environment due to multiple reflections is discussed. A method of computing the field distribution inside a room of arbitrary dimensions and electric characteristics of the walls is proposed. Measurements for different transmitter-receiver configurations and polarizations are presented. Based on computer simulation and measurement results some conclusions are made.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"7 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":"124097768","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.1998.730628
A. Leros, A. Alexandridis, K. Dangakis, P. Kostarakis
Radio propagation models for field strength prediction are essential for designing and installing a mobile radio communications system. Typical backpropagation neural network (BPN) models with different input parameters are developed and used to evaluate and assess the relative importance of a set of radio propagation parameters for field strength prediction. The NN models are trained on data measurements of propagation loss with terrain information taken in an urban area (Athens region) in the 900 MHz band. The performance of all NN models is evaluated by comparing their prediction error statistics of average value, standard deviation, root mean square and the correlation between their predicted values and the true data measurements. The NN model with the best performance provides an indication of the most important set of parameters for field strength prediction.
{"title":"Evaluation of radio propagation parameters for field strength prediction using neural networks","authors":"A. Leros, A. Alexandridis, K. Dangakis, P. Kostarakis","doi":"10.1109/APWC.1998.730628","DOIUrl":"https://doi.org/10.1109/APWC.1998.730628","url":null,"abstract":"Radio propagation models for field strength prediction are essential for designing and installing a mobile radio communications system. Typical backpropagation neural network (BPN) models with different input parameters are developed and used to evaluate and assess the relative importance of a set of radio propagation parameters for field strength prediction. The NN models are trained on data measurements of propagation loss with terrain information taken in an urban area (Athens region) in the 900 MHz band. The performance of all NN models is evaluated by comparing their prediction error statistics of average value, standard deviation, root mean square and the correlation between their predicted values and the true data measurements. The NN model with the best performance provides an indication of the most important set of parameters for field strength prediction.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"26 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":"128090641","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.1998.730632
V. Kontorovitch, R. Linares y M., F. Ramos A.
Many models to predict the propagation losses, the signal strength, etc., have been developed, but the vertiginous development of radio networks has prompted an examination of the propagation characteristics along the coverage area. However, the diversity in the available methods make the appropriate selection, for any particular situation, a hard task. We introduce an identification algorithm for mapping the propagation loss models (a feature of great relevance in radio network design).
{"title":"Identification approach for mapping the propagation losses models","authors":"V. Kontorovitch, R. Linares y M., F. Ramos A.","doi":"10.1109/APWC.1998.730632","DOIUrl":"https://doi.org/10.1109/APWC.1998.730632","url":null,"abstract":"Many models to predict the propagation losses, the signal strength, etc., have been developed, but the vertiginous development of radio networks has prompted an examination of the propagation characteristics along the coverage area. However, the diversity in the available methods make the appropriate selection, for any particular situation, a hard task. We introduce an identification algorithm for mapping the propagation loss models (a feature of great relevance in radio network design).","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"44 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":"132490089","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.1998.730662
K. Ito, Y. Okano, A. Hase, I. Ida
In this paper, accurate measurements for the SAR of modeled human heads using the brain equivalent phantom are presented. First, SARs of cubic and spherical phantoms in the vicinity of a dipole antenna are measured and compared with calculation. Secondly, a monopole antenna in a metal box, which simulates a mobile phone, is used. The operating frequency is considered only at 900 MHz. To enhance the accuracy of the experiments, the ingredients for the head model were carefully conditioned complying with COST 244 (1994).
{"title":"A tissue-equivalent solid phantom for estimation of interaction between human head and handset antenna","authors":"K. Ito, Y. Okano, A. Hase, I. Ida","doi":"10.1109/APWC.1998.730662","DOIUrl":"https://doi.org/10.1109/APWC.1998.730662","url":null,"abstract":"In this paper, accurate measurements for the SAR of modeled human heads using the brain equivalent phantom are presented. First, SARs of cubic and spherical phantoms in the vicinity of a dipole antenna are measured and compared with calculation. Secondly, a monopole antenna in a metal box, which simulates a mobile phone, is used. The operating frequency is considered only at 900 MHz. To enhance the accuracy of the experiments, the ingredients for the head model were carefully conditioned complying with COST 244 (1994).","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"9 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":"132930999","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.1998.730675
M.E. Ermutlu
Quadrifilar helix antennas have gained attention recently as antennas for satellite telephone handsets. Here a modification procedure is introduced for decreasing the length of the quadrifilar helix antenna. Two modified and two non-modified, quadrifilar antennas are designed and measured. The measurement results are shown.
{"title":"Modified quadrifilar helix antennas for mobile satellite communication","authors":"M.E. Ermutlu","doi":"10.1109/APWC.1998.730675","DOIUrl":"https://doi.org/10.1109/APWC.1998.730675","url":null,"abstract":"Quadrifilar helix antennas have gained attention recently as antennas for satellite telephone handsets. Here a modification procedure is introduced for decreasing the length of the quadrifilar helix antenna. Two modified and two non-modified, quadrifilar antennas are designed and measured. The measurement results 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":"130108186","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.1998.730647
J. Bergmann, F. Hasselmann, L. Pereira, M.G. Castello Branco
New microwave communication services have raised interest in base station antennas capable of radiating an omnidirectional pattern in the azimuthal plane, as is the case for cellular communications. Those antennas usually comprise linear dipole or slot arrays and, at higher frequencies, printed antenna arrays. Although such arrays may produce adequate radiation patterns, the main disadvantages of their use rest on reduced bandwidths and increasing losses with frequency due to phase and power control circuits. Alternatively, at microwave or millimetric ranges, one may employ reflector antenna configurations for base stations, comprising reflector surfaces shaped in order to radiate uniformly in the horizontal plane while taking into account free-space attenuation via cosecant squared-like power patterns in vertical planes, with radiated energy concentrated below the horizon line for reduced interference. The main characteristics of two such configurations are reviewed.
{"title":"Reflector antenna configurations for radio base stations in cellular communications","authors":"J. Bergmann, F. Hasselmann, L. Pereira, M.G. Castello Branco","doi":"10.1109/APWC.1998.730647","DOIUrl":"https://doi.org/10.1109/APWC.1998.730647","url":null,"abstract":"New microwave communication services have raised interest in base station antennas capable of radiating an omnidirectional pattern in the azimuthal plane, as is the case for cellular communications. Those antennas usually comprise linear dipole or slot arrays and, at higher frequencies, printed antenna arrays. Although such arrays may produce adequate radiation patterns, the main disadvantages of their use rest on reduced bandwidths and increasing losses with frequency due to phase and power control circuits. Alternatively, at microwave or millimetric ranges, one may employ reflector antenna configurations for base stations, comprising reflector surfaces shaped in order to radiate uniformly in the horizontal plane while taking into account free-space attenuation via cosecant squared-like power patterns in vertical planes, with radiated energy concentrated below the horizon line for reduced interference. The main characteristics of two such configurations are reviewed.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"44 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":"132896894","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.1998.730625
R. King
Communication between the shore and a ship and between ships makes use of frequencies from 1 to 30 MHz. The analysis presented provides new simple formulas for the ground wave along the surface of the sea. These include not only the range in which the surface of the sea is well-approximated by a plane but also the range where accurate account must be taken of the curvature of the spherical Earth. Of practical significance is the fact that when f/spl ges/10 MHz, the amplitude of an outgoing wave decreases much more rapidly than when f<10 MHz. This is true in the planar region when /spl rho//sub i//spl rho//sub c/.
{"title":"Electromagnetic ground-wave field of vertical antennas","authors":"R. King","doi":"10.1109/APWC.1998.730625","DOIUrl":"https://doi.org/10.1109/APWC.1998.730625","url":null,"abstract":"Communication between the shore and a ship and between ships makes use of frequencies from 1 to 30 MHz. The analysis presented provides new simple formulas for the ground wave along the surface of the sea. These include not only the range in which the surface of the sea is well-approximated by a plane but also the range where accurate account must be taken of the curvature of the spherical Earth. Of practical significance is the fact that when f/spl ges/10 MHz, the amplitude of an outgoing wave decreases much more rapidly than when f<10 MHz. This is true in the planar region when /spl rho//sub i/</spl rho/</spl rho//sub c/, and throughout the spherical region /spl rho//sub s/>/spl rho//sub c/.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"38 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":"117139694","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.1998.730640
Y. Kamiya, Y. Karasawa
It is expected that mobile communication systems will be able to overcome a multipath fading environment by using adaptive arrays. Particularly, in CDMA mobile communication systems, interferers which usually can not be extracted by the receiver filter and delayed signals arrive simultaneously with more than the degree of freedom of the array antenna. We propose a beamspace configuration for an adaptive array based on subband signal processing in order to avoid being caught in local minima and to lead adaptive algorithms to a better solution. Second, a novel beam selection method for the reduction of computational load is proposed. The performance of the proposed method is examined through computer simulations. Finally, it is concluded that the proposed method is more effective under a multipath fading environment than an element space one, and its computational load can be reasonably reduced.
{"title":"Beam space adaptive array based on subband signal processing","authors":"Y. Kamiya, Y. Karasawa","doi":"10.1109/APWC.1998.730640","DOIUrl":"https://doi.org/10.1109/APWC.1998.730640","url":null,"abstract":"It is expected that mobile communication systems will be able to overcome a multipath fading environment by using adaptive arrays. Particularly, in CDMA mobile communication systems, interferers which usually can not be extracted by the receiver filter and delayed signals arrive simultaneously with more than the degree of freedom of the array antenna. We propose a beamspace configuration for an adaptive array based on subband signal processing in order to avoid being caught in local minima and to lead adaptive algorithms to a better solution. Second, a novel beam selection method for the reduction of computational load is proposed. The performance of the proposed method is examined through computer simulations. Finally, it is concluded that the proposed method is more effective under a multipath fading environment than an element space one, and its computational load can be reasonably reduced.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"145 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":"124401341","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.1998.730668
W.C. Lee, Y. Song, J. Nam
Considering wireless CDMA communication system over a multipath fading channel, spatiotemporal processing at the receiver seems quite beneficial because as it can alleviate fading effects and suppress interference over the space and time domains simultaneously. This paper discusses efficient techniques for obtaining the beamformer weights in a recursive manner while maximizing SINR (signal to interferences plus noise). To show the superiority of the proposed composite processing for the spatiotemporal combiner, the BER and the SINR curves will be shown under the various environments.
{"title":"A spatiotemporal combiner for CDMA receiver using antenna arrays","authors":"W.C. Lee, Y. Song, J. Nam","doi":"10.1109/APWC.1998.730668","DOIUrl":"https://doi.org/10.1109/APWC.1998.730668","url":null,"abstract":"Considering wireless CDMA communication system over a multipath fading channel, spatiotemporal processing at the receiver seems quite beneficial because as it can alleviate fading effects and suppress interference over the space and time domains simultaneously. This paper discusses efficient techniques for obtaining the beamformer weights in a recursive manner while maximizing SINR (signal to interferences plus noise). To show the superiority of the proposed composite processing for the spatiotemporal combiner, the BER and the SINR curves will be shown under the various environments.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"2014 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":"125688657","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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