A dual-band unidirectional antenna using a hemispherical monopole with circular reflector

This paper presents a unidirectional antenna using a hemispherical monopole with circular reflector for dual-band wireless communication applications. It consists of a hemispherical monopole with a sheet of stub. The stub is placed over a hemispherical monopole for low frequency band operation. The radiation patterns are controlled by circular reflector together with circular ring and rectangular ring. At 2.4 GHz, the antenna radiates by a sheet of stub and a hemispherical monopole with rectangular ring. At 5.8 GHz, it radiates by a hemispherical monopole with circular ring. The proposed antenna is designed to operate between 2.4-2.5 GHz and 5.15-5.85 GHz with |S₁₁| <; -10 dB. The antenna has high gain and the radiation pattern at both bands are unidirectional beam. The simulated and measured results are presented.