A Slim Horizontally Polarized Omnidirectional Antenna Based on Turnstile Slot Dipole

Abstract—A novel horizontally polarized (HP) antenna with omnidirectional pattern is presented in this paper. The proposed antenna applies the concept of rotating electric field method to conventional slot dipoles. Two CPW-fed slot dipoles are placed in a perpendicularly conjugate form. By properly arranging the magnitude and phase of input signals, the omnidirectional pattern can be synthesized at broadside. A prototype is developed at the 2.6GHz band, which offers a horizontally polarized omnidirectional radiation pattern with gain of 2.5–3.4 dBi, and the measured antenna efficiency is greater than 73% through the operating band (2.4–2.8 GHz). Furthermore, a 20-dB polarization purity is achieved in this design. The overall volume of the proposed antenna is 22 × 22 × 90mm3 (0.19λ0×0.19λ0×0.78λ0). Distinct from the other proposed HP antennas provided with planar geometry, this antenna is slim in shape, and it can be readily integrated with vertical dipoles to form a polarization diversity system in current wireless router and AP applications.