Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730671
W. Young, B. Belzer, R. Olsen
The design of a two-element field/polarization diversity antenna for portable phones is considered. The antenna consists of a dipole terminated with a parallel loop capacitor combination. The antenna has a single feed at a point on the loop opposite the junction, and does not require external combining circuitry. The capacitor creates a phase shift between the dipole and loop currents, thereby greatly reducing the probability of deep nulls when the antenna is deployed in the vicinity of a fixed reflector, where standing wave patterns occur. Theoretical and simulation studies based on multiple incident plane wave fields are used to quantify antenna diversity gain in the presence of a fixed reflector. Simulation results are presented for three antenna types: a dipole antenna, a loop-dipole antenna without a capacitor, and the loop-dipole antenna with capacitor. The simulation results are verified by field measurements on an automated outdoor test range, where the incidence angle and distance from the reflector are varied. Both the simulation and field test results show that the loop-dipole-capacitor design provides a substantial diversity gain over the standard dipole antenna and over the loop-dipole antenna without the capacitor.
{"title":"A field/polarization diversity antenna for portable phones","authors":"W. Young, B. Belzer, R. Olsen","doi":"10.1109/APWC.1998.730671","DOIUrl":"https://doi.org/10.1109/APWC.1998.730671","url":null,"abstract":"The design of a two-element field/polarization diversity antenna for portable phones is considered. The antenna consists of a dipole terminated with a parallel loop capacitor combination. The antenna has a single feed at a point on the loop opposite the junction, and does not require external combining circuitry. The capacitor creates a phase shift between the dipole and loop currents, thereby greatly reducing the probability of deep nulls when the antenna is deployed in the vicinity of a fixed reflector, where standing wave patterns occur. Theoretical and simulation studies based on multiple incident plane wave fields are used to quantify antenna diversity gain in the presence of a fixed reflector. Simulation results are presented for three antenna types: a dipole antenna, a loop-dipole antenna without a capacitor, and the loop-dipole antenna with capacitor. The simulation results are verified by field measurements on an automated outdoor test range, where the incidence angle and distance from the reflector are varied. Both the simulation and field test results show that the loop-dipole-capacitor design provides a substantial diversity gain over the standard dipole antenna and over the loop-dipole antenna without the capacitor.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"45 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":"127037570","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.1998.730626
J. Colburn, M. Jensen, Y. Rahmat-Samii
The frequency fading characterization of the indoor ISM (902-928 MHz) channel are presented. This includes plots of the frequency-dependence of the fading and calculations of the correlation bandwidth. Finally, the measured diversity performance of three novel dual antenna configurations proposed for an ISM band wireless transceiver handset are presented. The diversity performance of these antenna geometries is assessed by measuring the power correlation coefficient of the signal received over each of the two antennas located on the handset. To evaluate the functionality of the measuring apparatus used in these experiments, the correlations of the received signal from two dipole antennas with various separations are measured, for which theoretically computed and previously measured envelope correlation coefficient data is available. Considerable effort is also directed at extraction of the fast fading information from the observed signal level, and its effect is detailed.
{"title":"Indoor ISM band multipath fading: frequency and antenna diversity","authors":"J. Colburn, M. Jensen, Y. Rahmat-Samii","doi":"10.1109/APWC.1998.730626","DOIUrl":"https://doi.org/10.1109/APWC.1998.730626","url":null,"abstract":"The frequency fading characterization of the indoor ISM (902-928 MHz) channel are presented. This includes plots of the frequency-dependence of the fading and calculations of the correlation bandwidth. Finally, the measured diversity performance of three novel dual antenna configurations proposed for an ISM band wireless transceiver handset are presented. The diversity performance of these antenna geometries is assessed by measuring the power correlation coefficient of the signal received over each of the two antennas located on the handset. To evaluate the functionality of the measuring apparatus used in these experiments, the correlations of the received signal from two dipole antennas with various separations are measured, for which theoretically computed and previously measured envelope correlation coefficient data is available. Considerable effort is also directed at extraction of the fast fading information from the observed signal level, and its effect is detailed.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"16 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":"115008840","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.1998.730624
C. Tzaras, S. Saunders, B. Evans
The present work describes a time series propagation model which considers three-dimensional urban path profiles where the buildings can have unequal heights, widths and spacings. Based on the Fresnel-Kirchhoff theory, it is mainly applicable to mobile satellite propagation channels where the final building face, just before the mobile user, is the most dominant source of diffraction phenomena. Although the model is considered to adopt a deterministic type of process, the outcome of the proposed work is achieved by considering only statistical distributions for the building path profile.
{"title":"A physical-statistical time-series model for the mobile-satellite channel","authors":"C. Tzaras, S. Saunders, B. Evans","doi":"10.1109/APWC.1998.730624","DOIUrl":"https://doi.org/10.1109/APWC.1998.730624","url":null,"abstract":"The present work describes a time series propagation model which considers three-dimensional urban path profiles where the buildings can have unequal heights, widths and spacings. Based on the Fresnel-Kirchhoff theory, it is mainly applicable to mobile satellite propagation channels where the final building face, just before the mobile user, is the most dominant source of diffraction phenomena. Although the model is considered to adopt a deterministic type of process, the outcome of the proposed work is achieved by considering only statistical distributions for the building path profile.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"24 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":"133177146","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 : 1900-01-01DOI: 10.1109/APWC.1998.730638
R. Dybdal, S. J. Curry
Adaptive techniques are commonly used to protect receiving antennas from interference. However, adaptive techniques have not been applied to transmitting antennas. An example of adaptively controlling a transmitting antenna is described. This adaptive transmit antenna concept was motivated by requirements for future personal communication systems. These antennas require broad antenna coverage to avoid antenna pointing requirements. This broad-coverage antenna requirement unavoidably results in multipath susceptibility that degrades communication performance. Rake receivers provide adaptive equalization and adaptive antenna element combining are well-known techniques to reduce multipath degradation for receiving systems. However, the performance of the transmit antenna remains degraded by multipath signals. Since the receive and transmit frequencies are separated, the adaptive receive combinations differ from those needed in the transmit case. This new adaptive transmit antenna provides a means to reduce multipath interference in the transmit case. Multipath distortions on transmission reduce the isolation between multiple users in CDMA systems, which is a well-known limit on overall system capacity.
{"title":"Adaptive transmit antenna","authors":"R. Dybdal, S. J. Curry","doi":"10.1109/APWC.1998.730638","DOIUrl":"https://doi.org/10.1109/APWC.1998.730638","url":null,"abstract":"Adaptive techniques are commonly used to protect receiving antennas from interference. However, adaptive techniques have not been applied to transmitting antennas. An example of adaptively controlling a transmitting antenna is described. This adaptive transmit antenna concept was motivated by requirements for future personal communication systems. These antennas require broad antenna coverage to avoid antenna pointing requirements. This broad-coverage antenna requirement unavoidably results in multipath susceptibility that degrades communication performance. Rake receivers provide adaptive equalization and adaptive antenna element combining are well-known techniques to reduce multipath degradation for receiving systems. However, the performance of the transmit antenna remains degraded by multipath signals. Since the receive and transmit frequencies are separated, the adaptive receive combinations differ from those needed in the transmit case. This new adaptive transmit antenna provides a means to reduce multipath interference in the transmit case. Multipath distortions on transmission reduce the isolation between multiple users in CDMA systems, which is a well-known limit on overall system capacity.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122230866","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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