Development of Ultra-Wideband Circularly Polarized Antenna Technology

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06431
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Communication/Network engineering
• Research Institution: Kumamoto University
• Principal Investigator: Fukusako Takeshi 熊本大学, 大学院先端科学研究部(工), 教授 (90295121)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: アンテナ / メタ表面 / 円偏波 / 広帯域特性

Outline of Final Research Achievements

In this research, we develop a meta-surface design technology for obtaining a circularly polarized antenna characteristics. In order to widen the band for generating circular polarization (CP), we considered a meta-surface wide band as a polariser to enhance the CP frequency range. The unit cell has a square shape, but each side of the meta surface has a rhombus structure that is inclined by 45° with respect to the unit cell, and irradiates linearly polarized light with an angle of 45° with respect to the x-axis. As a result, it was found that linearly polarized waves could be converted into circularly polarized waves over a wide band. It was also found to be effective to make the circumference circular. Finally, we also examined a cross-polarization polarization converter that applies the principle of a circularly polarized antenna.

Free Research Field

アンテナ工学

Academic Significance and Societal Importance of the Research Achievements

メタ表面が広帯域な諸特性を得るために，重要な知見を得ることができた．特に，メタ表面の設計段階においては，単位セルと周期境界条件で囲み，等価的に無限のアレーとした場合を仮定するのが通常だが，実際には有限のアレーとなる．この場合，端部の影響が深刻であるが，その影響を緩和する方法として，長方形の単位セルに有限周囲の辺が４５度となるひし形構造が有効であることが分かった．他，円形の周囲も有効であることも同時に確認できた．また，広帯域円偏波技術を応用したメタ表面偏波変換器も開発でき，今回の知見が応用できる．