An apparatus for controlling electric field distribution is provided, where the apparatus includes at least one portion of a portable electronic device, the portable electronic device includes a plurality of wireless communication functions respectively corresponding to different communication standards, and the plurality of wireless communication functions includes a mobile phone function and at least one other wireless communication function. The apparatus includes: a main antenna, connected to a first side of a PCB of the portable electronic device, for performing the mobile phone function; and a plurality of short trace structures, positioned at the first side of the PCB and connected to the PCB, wherein at least one of the plurality of short trace structures is selectively utilized as at least one short trace or utilized as at least one secondary antenna corresponding to the at least one other wireless communication function.