A mobile wireless communications device may include a housing having an upper portion and a lower portion, a dielectric substrate carried by the housing, circuitry carried by the dielectric substrate, and an audio output transducer carried by the upper portion of the housing and connected to the circuitry. The device may further include a user input interface carried by the housing and connected to the circuitry, and at least one auxiliary input/output device carried by the upper portion of the housing and connected to the circuitry. An antenna may also be carried within the lower portion of the housing comprising a pattern of conductive traces on the dielectric substrate.