Smart Wi-Fi Antenna With Reconfigurable Omnidirectional and Unidirectional Patterns

A compact pattern-reconfigurable antenna based on the electromagnetic complementary Huygens principle is developed in this letter. The vertically polarized antenna comprises a slot-loading shorted patch printed on the lower substrate and a mushroom structure printed on the upper substrate. The shorted patch is considered to have the same operating characteristics as the half-mode substrate integrated waveguide, which is equivalent to a slot magnetic dipole. The zeroth-order resonance is excited for the mushroom structure, which is equivalent to an electric dipole. The slot-loaded ground is used to expand the bandwidth. The omnidirectional and end fire directional radiation patterns are obtained by controlling the states of the mushroom with two PIN diodes. The antenna with a compact size of 0.19λ
₀
× 0.45λ
₀
× 0.033λ
₀
(λ
₀
represents the free space wavelength at 2.45 GHz) is developed. The measured −10 dB impedance bandwidth is covered the 2.4 GHz WLAN band (2.40–2.48 GHz). The proposed antenna shows great application potential for intelligent Wi-Fi communication systems.