HISAMATSU NAKANO

Recent Progress in Circularly Polarized Metamaterial Antennas

Circularly polarized (CP) antennas have been receiving considerable attention in response to recent developments in modern wireless communication systems. This keynote speech presents recent progress in four CP metamaterial antennas (metaantennas), comparing them with the corresponding natural CP antennas: (1) metaline antenna, (2) metaloop antenna, (3) metaspiral antenna, and (4) metacurl antenna. Investigation reveals that metaline antenna (1) exhibits a CP beam-scanning characteristic with change in frequency. Analysis of metaloop antenna (2) finds that it possesses a counter CP dual band characteristic, i.e., left-handed CP radiation across a specific frequency band and right-handed CP radiation across a different frequency band. Discussion of metaspiral antenna (3) is directed toward CP beam-scanning capability in both the azimuth and elevation planes. Exploration of metacurl antenna (4) finds that the antenna can be made to radiate a left-handed CP wave and a right-handed CP wave, where both have the same maximum gain.

Hisamatsu NAKANO has been with Hosei University since 1973, where he is currently a Professor Emeritus and a Special-appointment Researcher with the Electromagnetic Wave Engineering Research Institute attached to the graduate school. He has published over 340 articles in peer-reviewed journals and 11 books/book chapters. His significant contributions are the development of five integral equations for line antennas, the invention of an L-shaped wire/strip antenna feeding method, and the realization of numerous wideband antennas. He received the H. A. Wheeler Award (1994), the Chen-To Tai Distinguished Educator Award (2006), and the Distinguished Achievement Award (2016), all from the IEEE Antennas and Propagation Society. He was also a recipient of The Prize for Science and Technology from Japan's Minister of Education, Culture, Sports, Science and Technology (2010). Most recently, he was selected as a recipient of the Antenna Award of the European Association on Antennas and Propagation, EurAAP, (2020).