Antenna factors of half-wavelength dipole antennas with roberts balun


  • Ki-Chai Kim,

    1. Yeungnam University, Kyungsan, Korea
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    • Ki-Chai Kim graduated from the Department of Electronic Engineering, Korea, in 1984 and received his M.S. degree from Keio University in 1986 and his Ph.D. degree from there in 1989. In 1989, he became a Senior Researcher at the Korea Standard Research Institute (KSRI). In 1993, he was an Associate Professor at Fukuoka Institute of Technology. Since 1995, he has been an Associate Professor of Electrical Engineering of Yeungnam University, Korea. He has been engaged in research on application and measurement of antennas and electromagnetic waves. He received a 1988 Young Engineer Award from I.E.I.C.E. and a Paper Presentation Award in 1994 from the Institute of Electrical Engineers of Japan. He is a member of the Institute of Television Engineering and of IEEE.

  • Shinobu Tokumaru

    1. Faculty of Science and Technology, Keio University, Yokohama, Japan 223
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    • Shinobu Tokumaru graduated from the Department of Electrical Engineering, Keio University, in 1963 and received his Ph.D. degree from Tohoku University in 1968. At present, he is a Professor of Electrical Engineering at Keio University. He has been engaged in research on antennas and electromagnetic wave theory. He received an Inada Award and an Achievement Award from I.E.I.C.E. He is the author of Basic Electromagnetic Waves and Is There any Danger in Electromagnetic Waves? He is a member of IEEE.


To use antenna factors most effectively in either EMI measurement or the reference antenna method, the antenna factor is more accurately derived than the conventionally obtained value when a half-wave resonant dipole antenna with Roberts balun (ANSI C63.5 Specification) is placed on the ground plane. In the calculation, the antenna is treated as the boundary value problem of Maxwell's equations and is analyzed by the Galerkin moment method. The balun is treated using circuit theory based on power transmission mismatch. To confirm the validity of these theoretical calculations, the computed value of the antenna factor in free space is compared with the measured results by the standard site method and the standard antenna method. It is confirmed that the tendency of the numerical results agrees well with that of the measured values.