| Research Abstract |
Although there is a tendency to miniaturize the devices and circuits for mobile communications, the related an tennas have a difficulty in miniaturizing their structures due to their wavelength dependence. Actually, research and development for size reduction of the antennas such as microstrip antennas and F-shaped antennas have been promoted by many institutes, companies and laboratories.
The purpose of this research is placed on the development of a new type of small sized antennas based on the wavelength reduction effect of the high permittivity materials. By using the materials with the permittivity of 90, the planar antenna having the dimensions of 2cm X 1cm in area has been developed successfully at 300MHz band. This antenna has some interesting properties such as circular polarization, high efficiency, and size reduction.
Moreover, novel antenna, which is based on the self-complimentary structure and the traveling wave radiation nature, has been devised and developed at UHF band. It is obvious that this antenna has great advantages of ul tra-wide band operation from VHF to deep UHF as well as small sized structure.
The new types of small sized antennas for mobile communication systems such as wireless LAN, 3G PDC, blue-tooth, and so forth, have been developed successfully by using them.
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