A concept of pattern-reconfigurable singleelement antenna operating at 2.45 GHz is proposed in this paper. The antenna consists of two back-to-back half-mode substrate-integrated cavities with switchable shortings at both radiation apertures. One of the cavities is fed by an SMA probe while the other cavity is excited by the coupling through an aperture on the shared sidewall. This leads to the excitation of an even and an odd mode in the coupled cavities. Changing the states of the two switchable shortings leads to the switching between the even and odd coupled modes, which reconfigures the radiation pattern, and changes the main beam direction. The measured results on a fabricated prototype where the switches are mimicked by retractable screws validate the concept and illustrate that the main beam can be steered in the direction of either θ =12° or 36°.