LAUSR

A tri-band differentially fed dual-polarized slot (DFDPS) antenna is developed for indoor WiFi/5G wireless communications. The triband antenna is made up of two crossed slots with four pairs of L-shaped slots. The lower and higher bands are generated by the crossed slots, and the middle band is attributed to the L-shaped slots. Eight shorting pins are introduced for improving the impedance matching for all the three bands. A substrate-integrated waveguide (SIW) cavity is employed to back the antenna for unidirectional radiation. Two orthogonal feedlines are applied to differentially feed the antenna for dual polarization. The antenna has a low-profile of about $0.054~\lambda _{\mathbf {2.4}}$ , where $\lambda _{\mathbf {2.4}}$ is the wavelength at the lowest frequency of 2.4 GHz in free space. It is shown that the triband antenna can operate in three bands of 2.4–2.51, 3.29–3.6, and 4.8–5.05 GHz with good unidirectional patterns.