An object of the invention is to provide a communication terminal capable
of keeping the reception sensitivity good if the communication terminal
is placed on a metal plate with the communication terminal laid on its
side without the need for changing the size or the design of the main
body of the communication terminal. A board (125) to which an antenna
(107) is connected is provided inside a lower casing (105). The board
(125) is provided with a GND plane to which a radiating element (121) is
connected. An auxiliary bottom board (123) is joined to the radiating
element (121) in a roughly perpendicular direction thereto. The radiating
element (121) and the auxiliary bottom board (123) are conductors. A
high-frequency current (131) flows into the board (125). Since a
high-frequency current (133) of an opposite phase flows through a metal
plate (141) because of the mirror image effect in a state in which the
communication terminal is placed on the metal plate (141), the
high-frequency current (131) is canceled and the radiation of the antenna
(107) is weakened. However, the components perpendicular to the metal
plate (141) do not cancel each other because of the mirror image effect
and thus the radiating element (121) forms a dipole antenna symmetrically
with the metal plate (141).