Embodiments described herein relate a mobile communication device and techniques to suppress deterioration of antenna characteristics. The mobile device includes metallic members that are disposed around, or in portions of a casing of the mobile device. The metallic member is grounded directly to a ground plane of the mobile device at a first predetermined position. The grounded metallic member forms a stub line that cancels a flow of electric current though the metallic member. Furthermore, the metallic member is also connected to the ground plane, at a second predetermined location, via a resonant circuit. The mobile device is capable of adjusting a phase of the antenna current flowing through the device, when the mobile device is being operated by a user, and thus suppresses deterioration of antenna characteristics in certain desired frequency bands.