A small multi-mode antenna in which a single feeding point can be used
commonly for multiple frequencies and an RF module using such antenna for
use in less-costly and small multimedia wireless apparatus is provided.
The antenna is configured such that a single feeding point 4 which is
common for multiple frequencies is set up at one end of a radiating
conductor 1, a first one-port resonant circuit 2 is connected to the one
end thereof, and a second one-port resonant circuit 3 is connected to the
other end of the radiating conductor 1. With a conductance component of
admittance in view from the feeding point 4 toward free space equaling
the characteristic admittance in the RF circuit, a susceptance component
of the admittance is canceled out by the resonant circuit 2 connected to
the feeding point 4 for multiple frequencies.