Projector of the Sharpest Beam of Electric Waves

Historical Review of Research and Development of Linear Antennas in Tohoku University

“…The first report describing methods to obtain a sharp beam by using parasitic elements was published by Uda of Tohoku University, Japan in 1925 [1], and details of the geometry of the Yagi-Uda antenna were reported by Yagi and Uda in 1926 [2].…”

“…The invention and development of the Yagi-Uda antennas in 1925 [1], [2] and the self-complementary antennas in 1948 [3]- [5] were the highlights of antenna research in Japan which were invented both in Tohoku University. Yagi-Uda antennas were also used for the long-range radio wave communications between small islands and main land Japan.…”

Characteristics of High-Gain Wideband Ring Loop Antenna and its Application

“…Until now, YagiUda antenna of the linear polarization characteristics is mainly utilized in the transmitting and receiving antenna of the UHF band. However, the band property is narrow band on this Yagi-Uda antenna [7] [8]. Therefore, in recent years, band property is improved using the looped antenna element, and circularly polarized wave Yagi-Uda array antenna, which enabled the circularly polarized wave, are considered.…”

Electromagnetic Waves Radiation by a Vibrators System With Variable Surface Impedance

“…Systems of perfectly conducting vibrators are widely used both as antennas with directional axial radiation and as a multi-element antenna array in the meter and decimeter wave bands [1][2][3][4][5][6][7][8][9][10]. An additional parameter, which allows forming a required amplitude-phase distribution of vibrators currents, and thus, modifying and optimizing the electromagnetic characteristics of the system as a whole, can be distributed surface impedance (both constant and variable along the vibrator length) [11][12][13][14][15][16].…”