Pub Date : 1998-11-01DOI: 10.1109/APWC.1998.730664
S. Y. London, V. P. Leonov, P. Koert, L. Susman
A high power, wideband HF phased array is being constructed as part of the High Frequency Active Auroral Research Program (HAARP) in Galkona, Alaska. Extensive testing of a demonstration prototype (DP) version of the array discovered undesirable feed resonance effects at discrete frequencies and excessive tower currents under simulated scanned conditions. Analyses and subsequent measurements pointed to even mode excitations of the dipole as the cause of these difficulties. To solve this problem the feed system was modified with the goal of controlling both the even and odd mode excitations. A novel wideband high efficiency hybrid-balun and balanced AMU (antenna matching unit) was designed and tested confirming the superiority of the new feed arrangement. A low-band version is being incorporated into the DP testbed and extends the low-band performance by 20%, with lower loss and reduced tower currents. The feed design is further evaluated by calculating the average efficiency of the array system, which is within 0.25 to 1.5 dB of its theoretical maximum, depending on frequency.
{"title":"Improved feed system design for a wideband dipole array","authors":"S. Y. London, V. P. Leonov, P. Koert, L. Susman","doi":"10.1109/APWC.1998.730664","DOIUrl":"https://doi.org/10.1109/APWC.1998.730664","url":null,"abstract":"A high power, wideband HF phased array is being constructed as part of the High Frequency Active Auroral Research Program (HAARP) in Galkona, Alaska. Extensive testing of a demonstration prototype (DP) version of the array discovered undesirable feed resonance effects at discrete frequencies and excessive tower currents under simulated scanned conditions. Analyses and subsequent measurements pointed to even mode excitations of the dipole as the cause of these difficulties. To solve this problem the feed system was modified with the goal of controlling both the even and odd mode excitations. A novel wideband high efficiency hybrid-balun and balanced AMU (antenna matching unit) was designed and tested confirming the superiority of the new feed arrangement. A low-band version is being incorporated into the DP testbed and extends the low-band performance by 20%, with lower loss and reduced tower currents. The feed design is further evaluated by calculating the average efficiency of the array system, which is within 0.25 to 1.5 dB of its theoretical maximum, depending on frequency.","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":"117063508","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.1998.730684
N. Herscovici, Z. Sipus, D. Bonefačić
For more than 25 years the circularly polarized single-fed microstrip patch have been considered to be extremely narrow-band. The performances reported are almost exclusively related to single patches printed on a dielectric substrate, which partially explains the frequency characteristics. The antenna proposed is a variation of the 'almost-square' patch and exhibits a theoretical axial ratio of less than 2.5 dB over a 10% bandwidth. The antenna was designed for PCN and PCS applications.
{"title":"Circularly polarized single-fed microstrip patch for wireless communications","authors":"N. Herscovici, Z. Sipus, D. Bonefačić","doi":"10.1109/APWC.1998.730684","DOIUrl":"https://doi.org/10.1109/APWC.1998.730684","url":null,"abstract":"For more than 25 years the circularly polarized single-fed microstrip patch have been considered to be extremely narrow-band. The performances reported are almost exclusively related to single patches printed on a dielectric substrate, which partially explains the frequency characteristics. The antenna proposed is a variation of the 'almost-square' patch and exhibits a theoretical axial ratio of less than 2.5 dB over a 10% bandwidth. The antenna was designed for PCN and PCS applications.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"81 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":"126255165","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.1998.730686
H. Jung, C. Seo
We present an analysis of a microstrip elliptical patch fed by coaxial cable using the moment method. After finding the exact Green's function, the input impedance is calculated by employing the reaction integration method and the moment method in the spectral domain together and proving its validity compared with experimental values. The attachment mode is used to consider the singularity and the discontinuity of the currents occurring at the attachment point between the probe and the patch when fed by coaxial cable.
{"title":"Analysis of elliptical microstrip patch antenna by considering attachment mode of current","authors":"H. Jung, C. Seo","doi":"10.1109/APWC.1998.730686","DOIUrl":"https://doi.org/10.1109/APWC.1998.730686","url":null,"abstract":"We present an analysis of a microstrip elliptical patch fed by coaxial cable using the moment method. After finding the exact Green's function, the input impedance is calculated by employing the reaction integration method and the moment method in the spectral domain together and proving its validity compared with experimental values. The attachment mode is used to consider the singularity and the discontinuity of the currents occurring at the attachment point between the probe and the patch when fed by coaxial cable.","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":"126989349","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.1998.730674
C.H. Ho, D. Huang, B. Wu
This paper presents a new GPS slot antenna consisting of six quarter-wavelength resonant slots. Each of the six resonant slots is rolled a half-turn around the cylindrical laminate and maintains constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. The printed cylindrical slot antenna presented is useful in applications where low-profile installation is required on a highly dynamic aircraft. This new printed GPS antenna provides compact size, low cost, ease of mass production, near-hemispherical radiation coverage and circular polarization properties. Experimental results show that the new hexafilar antennas have a 3 dB beamwidth of more than 120/spl deg/ and a front-back ratio of more than 15 dB.
{"title":"A new GPS hexafilar slot antenna","authors":"C.H. Ho, D. Huang, B. Wu","doi":"10.1109/APWC.1998.730674","DOIUrl":"https://doi.org/10.1109/APWC.1998.730674","url":null,"abstract":"This paper presents a new GPS slot antenna consisting of six quarter-wavelength resonant slots. Each of the six resonant slots is rolled a half-turn around the cylindrical laminate and maintains constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. The printed cylindrical slot antenna presented is useful in applications where low-profile installation is required on a highly dynamic aircraft. This new printed GPS antenna provides compact size, low cost, ease of mass production, near-hemispherical radiation coverage and circular polarization properties. Experimental results show that the new hexafilar antennas have a 3 dB beamwidth of more than 120/spl deg/ and a front-back ratio of more than 15 dB.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"42 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":"127459488","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.1998.730673
C.H. Ho, D. Huang, B. Wu
This paper presents a new GPS quadrifilar slot antenna consisting of four quarter-wavelength crank slots. The four resonant crank slots are equally placed around the circumference of a cylindrical laminate and they maintain a constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. This new resonant helical slot antenna has a beamwidth of more than 120 degrees and a null at the back, which means an excellent capability for receiving low-elevation satellite signals and rejecting multipath interference.
{"title":"A novel crank quadrifilar slot antenna for GPS hand-held receivers","authors":"C.H. Ho, D. Huang, B. Wu","doi":"10.1109/APWC.1998.730673","DOIUrl":"https://doi.org/10.1109/APWC.1998.730673","url":null,"abstract":"This paper presents a new GPS quadrifilar slot antenna consisting of four quarter-wavelength crank slots. The four resonant crank slots are equally placed around the circumference of a cylindrical laminate and they maintain a constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. This new resonant helical slot antenna has a beamwidth of more than 120 degrees and a null at the back, which means an excellent capability for receiving low-elevation satellite signals and rejecting multipath interference.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"52 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":"130650302","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.1998.730681
N. Fayyaz, S. Safavi-Naeini, E. Shin
A novel design for increasing the bandwidth of a rectangular patch antenna is introduced and implemented. The design concept involves terminating a suitable point of the patch with an appropriately designed stub. This stub simultaneously acts as a short circuit and impedance thereby creating two close resonances. This new design is very useful since it improves the bandwidth of a traditional rectangular patch antenna by a factor of three.
{"title":"A new wideband rectangular patch antenna","authors":"N. Fayyaz, S. Safavi-Naeini, E. Shin","doi":"10.1109/APWC.1998.730681","DOIUrl":"https://doi.org/10.1109/APWC.1998.730681","url":null,"abstract":"A novel design for increasing the bandwidth of a rectangular patch antenna is introduced and implemented. The design concept involves terminating a suitable point of the patch with an appropriately designed stub. This stub simultaneously acts as a short circuit and impedance thereby creating two close resonances. This new design is very useful since it improves the bandwidth of a traditional rectangular patch antenna by a factor of three.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"51 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":"116518969","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.1998.730627
Honggang Zhang, T. Yoshina, S. Ito, Y. Nagasawa
A UTD-based technique for solving multiple diffraction problems of buildings in mobile cellular situations is derived. For microwave propagation over building rooftop or along building surface at grazing incidence, the slope diffraction term plays an important role in calculating the double-edge diffraction coefficient and should be combined with the modified multiplication factor further. Good agreements indicate that this prediction model may be a helpful tool for cellular mobile system planning.
{"title":"A UTD-based approach to predicting diffraction by buildings for cellular mobile communication","authors":"Honggang Zhang, T. Yoshina, S. Ito, Y. Nagasawa","doi":"10.1109/APWC.1998.730627","DOIUrl":"https://doi.org/10.1109/APWC.1998.730627","url":null,"abstract":"A UTD-based technique for solving multiple diffraction problems of buildings in mobile cellular situations is derived. For microwave propagation over building rooftop or along building surface at grazing incidence, the slope diffraction term plays an important role in calculating the double-edge diffraction coefficient and should be combined with the modified multiplication factor further. Good agreements indicate that this prediction model may be a helpful tool for cellular mobile system planning.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"106 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":"123444477","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.1998.730672
J. P. Casey, C.T. Fessenden, R. Bansal
Compared with the center-fed dipole, an asymmetrically fed linear radiator is shown to offer improved low-angle, satellite communications antenna performance by greatly reducing the severity of the multipath signals near the horizon. Numerical analysis (NEC) and measured data show that the improvement is achieved by increasing the upper/lower half-space energy ratio, particularly in the region near the horizon.
{"title":"Asymmetrically fed linear antenna for low-angle VHF/UHF satellite communications","authors":"J. P. Casey, C.T. Fessenden, R. Bansal","doi":"10.1109/APWC.1998.730672","DOIUrl":"https://doi.org/10.1109/APWC.1998.730672","url":null,"abstract":"Compared with the center-fed dipole, an asymmetrically fed linear radiator is shown to offer improved low-angle, satellite communications antenna performance by greatly reducing the severity of the multipath signals near the horizon. Numerical analysis (NEC) and measured data show that the improvement is achieved by increasing the upper/lower half-space energy ratio, particularly in the region near the horizon.","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":"115429789","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.1998.730630
F. Aryanfar, S. Safavi-Naeini
For new service deployment and expansion and improvement of existing systems accurate path loss prediction in urban micro- and pico-cellular environments is an important design verification step.
{"title":"Electromagnetic modeling of radio wave propagation in micro- and pico-cellular environments","authors":"F. Aryanfar, S. Safavi-Naeini","doi":"10.1109/APWC.1998.730630","DOIUrl":"https://doi.org/10.1109/APWC.1998.730630","url":null,"abstract":"For new service deployment and expansion and improvement of existing systems accurate path loss prediction in urban micro- and pico-cellular environments is an important design verification step.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"368 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":"115784254","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.1998.730650
M. Stuchly, M. Okoniewski, M. Rahman, K. Caputa
Many wireless communication devices are used with their antennas in close proximity to the human head. This results in changes in the antenna characteristics that affect the communications performance and in the deposition of microwave energy in the user's head. The amount of power deposited in the human body is limited to a given maximum value, according to current USA (FCC) and other regulation. We show here the feasibility and effectiveness of the FDTD method for complete evaluation of the human interaction with the performance of antennas for hand-held devices. A dual-frequency antenna and single-band monopole antennas are evaluated. Additionally, an accurate algorithm for computations of the power deposited in 1 g of tissue is introduced.
{"title":"Modeling of human interaction with antennas using the finite difference time domain technique","authors":"M. Stuchly, M. Okoniewski, M. Rahman, K. Caputa","doi":"10.1109/APWC.1998.730650","DOIUrl":"https://doi.org/10.1109/APWC.1998.730650","url":null,"abstract":"Many wireless communication devices are used with their antennas in close proximity to the human head. This results in changes in the antenna characteristics that affect the communications performance and in the deposition of microwave energy in the user's head. The amount of power deposited in the human body is limited to a given maximum value, according to current USA (FCC) and other regulation. We show here the feasibility and effectiveness of the FDTD method for complete evaluation of the human interaction with the performance of antennas for hand-held devices. A dual-frequency antenna and single-band monopole antennas are evaluated. Additionally, an accurate algorithm for computations of the power deposited in 1 g of tissue is introduced.","PeriodicalId":246376,"journal":{"name":"1998 IEEE-APS Conference on Antennas and Propagation for Wireless Communications (Cat. No.98EX184)","volume":"09 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":"130156978","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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