Horizontally polarized omnidirectional antenna using open-ended cavity

In this paper, a horizontally polarized antenna is proposed for the omnidirectional coverage in the 2.4-GHz WLAN band. The azimuthal omnidirectional pattern is provided by an open-ended cavity with a probe feed. The proposed structure exhibits good imitation of the ideal magnetic current with similar isotropic radiation pattern, even though with asymmetrical structure. A series of numerical simulations are unitized to prove the design strategy. The proposed antenna has a compact volume of 88.5×42×6 mm³ (0.71λ0×0.34λ0×0.05λ0, λ0 is the free-space wavelength at 2.4 GHz) and the gain variation is less than 1.3 dB in the azimuthal plane within the desired bandwidth of 2.4–2.48 GHz, exhibiting good omnidirectional radiation pattern in a sabre-like structure which is different from previous design.