Compact Dual-band Horizontally Polarized Omnidirectional Antenna

A compact horizontally polarized (HP) omnidirectional antenna with dual-band characteristic is presented in this article. The antenna is composed of a 3D radiation slot for omnidirectional pattern and a folded metal patch for coupling feed. Owing to the offset of the feed patch, the proposed HP omnidirectional antenna has a wide operating band in high frequency. The entire structure of the antenna is completely composed of metal and contains no medium, so the antenna has high efficiency. The antenna volume is 30mm×25mm×10mm ( 0.24λ 0 ×0.2λ 0 ×0.08λ 0 , λ 0 is the wavelength of corresponding lowest operating frequency). Simulated results show that this antenna has two 10dB return loss operating bandwidth of 5.6% (2.41–2.55 GHz) and 22.6% (4.75-5.96GHz). In addition, the antenna exhibits good omnidirectional characteristics, with gain variation in horizontal plane being less than 2.4 dB among 2.41-2.55 GHz and less than 4.9 dB among 4.75-5.96GHz.