Mobile device with tri-band antennas incorporated into a metal back side

A device comprising:

• a back side comprising a face;
• a first end, and a second end opposite the first end;
• an edge extending from the face, the edge encircling the face and having (i) respective opposing end surfaces at the first end and the second end, and (ii) opposing side surfaces joined between the end surfaces by corner portions of the edge;
• a conducting central portion located externally on the face;
• a first antenna located externally at the first end and electrically separated from the conducting central portion by a first gap extending across the face between the side surfaces of the edge;
• a second antenna located externally at the second end and electrically separated from the conducting central portion by a second gap extending across the face between the side surfaces of the edge, and each of the first antenna and the second antenna comprising:
• a first respective radiating arm having:
• a face portion covering an area of the face bounded by the respective gap, the end surface at a respective end, and the side surfaces;
• and
• at least two edge portions wrapping from the face portion around to the side surfaces of the edge and to the corner portions of the edge, and
• at least two further respective radiating arms extending from respective edge portions of the first respective radiating arm towards each other along the respective end surface, the first respective radiating arm and the at least two further respective radiating arms configured to resonate in at least three frequency ranges;
• one or more antenna feeds connected to each of the first antenna and the second antenna, and electrically separated from the conducting central portion;
• and,
• a switch configured to select one or more of the first antenna and the second antenna for operation.