Abstract:
A design procedure for minimum-Q spherical wire antennas (SWAs) of arbitrarily small electrical size is derived. Special cases of circularly polarized and self-tuned desi...Show MoreMetadata
Abstract:
A design procedure for minimum-Q spherical wire antennas (SWAs) of arbitrarily small electrical size is derived. Special cases of circularly polarized and self-tuned designs are investigated, where the latter is elliptically polarized and provides the lowest \boldsymbol {Q} for any configuration of radiated spherical waves in the electrically small regime. The designs are tested in simulation to find that the polarizations agree with the theoretical predictions. The basis for these theoretical predictions—spherical wave expansion—also provides \boldsymbol {Q} estimates which are attained in the self-tuned (lowest \boldsymbol {Q} electrically small spherical wire) case over a range of electrical sizes for a large number of wires. For a more practical number of wires, a special case is synthesized with electrical size \boldsymbol {ka=0.25} to obtain a quality factor which is 1.03 times the lower bound on SWA \boldsymbol {Q} , the lowest \boldsymbol {Q} relative to this lower bound in the literature.
Published in: IEEE Transactions on Antennas and Propagation ( Volume: 73, Issue: 4, April 2025)
Funding Agency:
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada
Alexander B. Murray (Graduate Student Member, IEEE) received the B.Sc. degree (Hons.) in electrical engineering from the University of Alberta, Edmonton, AB, Canada, in 2022, where he is currently pursuing the Ph.D. degree in electrical engineering.
He has been an undergraduate student researcher in the areas of harmonic radar, infrared fiber amplifiers, nuclear magnetic resonance, and folded dipole antennas. His current r...Show More
Alexander B. Murray (Graduate Student Member, IEEE) received the B.Sc. degree (Hons.) in electrical engineering from the University of Alberta, Edmonton, AB, Canada, in 2022, where he is currently pursuing the Ph.D. degree in electrical engineering.
He has been an undergraduate student researcher in the areas of harmonic radar, infrared fiber amplifiers, nuclear magnetic resonance, and folded dipole antennas. His current r...View more
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada
Ashwin K. Iyer (Senior Member, IEEE) received the B.A.Sc. (Hons.), M.A.Sc., and Ph.D. degrees in electrical engineering from the University of Toronto, Toronto, ON, Canada, in 2001, 2003, and 2009, respectively, where he was involved in the discovery and development of the negative-refractive-index transmission-line approach to metamaterial design and the realization of metamaterial lenses for free-space microwave subdiff...Show More
Ashwin K. Iyer (Senior Member, IEEE) received the B.A.Sc. (Hons.), M.A.Sc., and Ph.D. degrees in electrical engineering from the University of Toronto, Toronto, ON, Canada, in 2001, 2003, and 2009, respectively, where he was involved in the discovery and development of the negative-refractive-index transmission-line approach to metamaterial design and the realization of metamaterial lenses for free-space microwave subdiff...View more
Contents Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada
Alexander B. Murray (Graduate Student Member, IEEE) received the B.Sc. degree (Hons.) in electrical engineering from the University of Alberta, Edmonton, AB, Canada, in 2022, where he is currently pursuing the Ph.D. degree in electrical engineering.
He has been an undergraduate student researcher in the areas of harmonic radar, infrared fiber amplifiers, nuclear magnetic resonance, and folded dipole antennas. His current research interests include theoretical limitations of electrically small antennas, and their design as informed by these limitations—both of these with an emphasis on analyses utilizing antenna quality factor.
Mr. Murray has been a member of the IEEE Antennas and Propagation Society since 2022. He was a recipient of the Natural Sciences and Engineering Research Council of Canada (NSERC) Graduate Scholarship (Master’s Level) in 2022, was a recipient of the IEEE AP-S Eugene F. Knott Memorial Pre-Doctoral Research Grant and the IEEE AP-S Fellowship, in 2023, and received the NSERC Postgraduate Scholarship (Doctoral Level) and Alberta Innovates Graduate Student Scholarship (Doctoral Level), in 2024. He was a member of a finalist student group in the 2022 AP-S/URSI Symposium Student Design Contest, Denver, CO, USA, which featured designs on the topic of miniaturized antennas for the Internet of Things (IoT) applications. He is the student author of a paper presented at the 2024 AP-S/URSI Symposium in Florence, Italy, on the subject of antenna quality factor which received an honorable mention in the Symposium’s Student Paper Competition.
Alexander B. Murray (Graduate Student Member, IEEE) received the B.Sc. degree (Hons.) in electrical engineering from the University of Alberta, Edmonton, AB, Canada, in 2022, where he is currently pursuing the Ph.D. degree in electrical engineering.
He has been an undergraduate student researcher in the areas of harmonic radar, infrared fiber amplifiers, nuclear magnetic resonance, and folded dipole antennas. His current research interests include theoretical limitations of electrically small antennas, and their design as informed by these limitations—both of these with an emphasis on analyses utilizing antenna quality factor.
Mr. Murray has been a member of the IEEE Antennas and Propagation Society since 2022. He was a recipient of the Natural Sciences and Engineering Research Council of Canada (NSERC) Graduate Scholarship (Master’s Level) in 2022, was a recipient of the IEEE AP-S Eugene F. Knott Memorial Pre-Doctoral Research Grant and the IEEE AP-S Fellowship, in 2023, and received the NSERC Postgraduate Scholarship (Doctoral Level) and Alberta Innovates Graduate Student Scholarship (Doctoral Level), in 2024. He was a member of a finalist student group in the 2022 AP-S/URSI Symposium Student Design Contest, Denver, CO, USA, which featured designs on the topic of miniaturized antennas for the Internet of Things (IoT) applications. He is the student author of a paper presented at the 2024 AP-S/URSI Symposium in Florence, Italy, on the subject of antenna quality factor which received an honorable mention in the Symposium’s Student Paper Competition.View more
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada
Ashwin K. Iyer (Senior Member, IEEE) received the B.A.Sc. (Hons.), M.A.Sc., and Ph.D. degrees in electrical engineering from the University of Toronto, Toronto, ON, Canada, in 2001, 2003, and 2009, respectively, where he was involved in the discovery and development of the negative-refractive-index transmission-line approach to metamaterial design and the realization of metamaterial lenses for free-space microwave subdiffraction imaging.
He is currently a Professor with the Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada, where he serves as the Director of the Microwave, Millimeter-Wave, and MetaDevices (M3) Laboratory and the Co-Director of the Hub for Applied Research in Defence and Dual-use Technologies (HARDD-Tech). He has co-authored a number of highly cited articles and four book chapters on the subject of metamaterials. His research interests include novel RF/microwave circuits and techniques, fundamental electromagnetic theory, antennas, sensors, and engineered metamaterials, with an emphasis on their applications to microwave and optical devices, defense technologies, and biomedicine.
Dr. Iyer is a member of several IEEE AP-S Committees including its Education Committee and Membership and Benefits Committee, and he served on its Administrative Committee from 2021 to 2024. He was a recipient of the IEEE AP-S R. W. P. King Award in 2008, the IEEE AP-S Donald G. Dudley Jr. Undergraduate Teaching Award in 2015, the University of Alberta Provost’s Award for Early Achievement of Excellence in Undergraduate Teaching in 2014, and the University of Alberta Rutherford Award for Excellence in Undergraduate Teaching in 2018. His students are the recipients of several major national and international awards for their research. He serves/served as a Technical Program Committee Co-Chair for the 2025, 2020, 2016, and 2015 AP-S/URSI International Symposia. He was the founding Co-Chair of the IEEE Northern Canada Section’s Award-Winning Joint Chapter of the AP-S and MTT-S from 2012 to 2024. From 2012 to 2018, he was an Associate Editor of IEEE Transactions on Antennas and Propagation. He has been serving as a Track Editor since 2019. He was a Guest Editor of IEEE Transactions on Antennas and Propagation Special Issue on Recent Advances in Metamaterials and Metasurfaces. He is a Registered Member of the Association of Professional Engineers and Geoscientists of Alberta.
Ashwin K. Iyer (Senior Member, IEEE) received the B.A.Sc. (Hons.), M.A.Sc., and Ph.D. degrees in electrical engineering from the University of Toronto, Toronto, ON, Canada, in 2001, 2003, and 2009, respectively, where he was involved in the discovery and development of the negative-refractive-index transmission-line approach to metamaterial design and the realization of metamaterial lenses for free-space microwave subdiffraction imaging.
He is currently a Professor with the Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada, where he serves as the Director of the Microwave, Millimeter-Wave, and MetaDevices (M3) Laboratory and the Co-Director of the Hub for Applied Research in Defence and Dual-use Technologies (HARDD-Tech). He has co-authored a number of highly cited articles and four book chapters on the subject of metamaterials. His research interests include novel RF/microwave circuits and techniques, fundamental electromagnetic theory, antennas, sensors, and engineered metamaterials, with an emphasis on their applications to microwave and optical devices, defense technologies, and biomedicine.
Dr. Iyer is a member of several IEEE AP-S Committees including its Education Committee and Membership and Benefits Committee, and he served on its Administrative Committee from 2021 to 2024. He was a recipient of the IEEE AP-S R. W. P. King Award in 2008, the IEEE AP-S Donald G. Dudley Jr. Undergraduate Teaching Award in 2015, the University of Alberta Provost’s Award for Early Achievement of Excellence in Undergraduate Teaching in 2014, and the University of Alberta Rutherford Award for Excellence in Undergraduate Teaching in 2018. His students are the recipients of several major national and international awards for their research. He serves/served as a Technical Program Committee Co-Chair for the 2025, 2020, 2016, and 2015 AP-S/URSI International Symposia. He was the founding Co-Chair of the IEEE Northern Canada Section’s Award-Winning Joint Chapter of the AP-S and MTT-S from 2012 to 2024. From 2012 to 2018, he was an Associate Editor of IEEE Transactions on Antennas and Propagation. He has been serving as a Track Editor since 2019. He was a Guest Editor of IEEE Transactions on Antennas and Propagation Special Issue on Recent Advances in Metamaterials and Metasurfaces. He is a Registered Member of the Association of Professional Engineers and Geoscientists of Alberta.View more