The present invention provides an antenna for multiple bands employing a
single antenna element 10, capable of operating in multiple frequency
bands, and ideal for size reduction purposes. One end A of an antenna
element 10 is electrically connected to a feeding point 12 and
intermediate points B and C and the other end thereof is electrically
connected via switches SWb, SWc, and SWd to a ground conductor 14. The
electrical lengths of the antenna element 10 from the terminal to the
intermediate points B and C plus connection lines from these points via
the switches SWb and SWc to the ground conductor 14 and the electrical
length from the one end A to the other end D plus a connection line from
the other end via the switch SWd to the ground conductor 14 are set to be
capable of resonating different desired frequency bands. By closing one
of the switches SWb, SWc, and SWd, one of the desired frequencies can be
selected and the antenna can resonate with that frequency. Thus, the
antenna employing the single antenna element 10 can operate in multiple
frequency bands.