A mobile wireless communications device may include a portable housing that may include an electrically conductive continuous ring defining a perimeter of the portable housing. The electrically conductive continuous ring may be configured to function as an antenna. The mobile wireless communications device may further include a printed circuit board (PCB) carried by the portable housing and may include an electrically conductive layer defining a ground plane. The mobile wireless communications device may further include wireless transceiver circuitry carried by the PCB and coupled to the antenna. The mobile wireless communications device may also include an electrically conductive shorting member coupled between the electrically conductive continuous ring and the ground plane.