SPHERICAL SUPER WIDEBAND (SWB) MONOPOLE ANTENNA WITH MICROMACHINED TAPERED FEEDING LINE
Cheolbok Kim, Kyoung Tae Kim, Yong-Kyu Yoon and Jong Kyu Kim
A spherical super wideband (SWB) monopole antenna is designed, fabricated and characterized. The low frequency cutoff is mainly determined by the diameter of the conductive sphere monopole antenna at its quarter wavelength, where the sphere serves as a main radiator. The upper cutoff is greatly enlarged by using the tapered feeding line between the coaxial and the sphere, which is fabricated using thick photopatternable polyurethane (D50, MacDerimid Inc.) and 3D multidirectional UV lithography. The implemented SWB antenna has a 10dB-bandwidth between 2.4 and 23.2 GHz (a ratio bandwidth of 9.7:1), and an omni-directional radiation pattern with a maximum gain of approximately 2.9 dBi at 10 GHz.
Keywords: 3D multidirectional UV lithography, antenna feeds, antenna radiation patterns, broadband antennas, micromachining, monopole antennas and ultraviolet lithography