A multi-mode radio module (22) comprises a terminal (11) for connection to
an antenna (10). A transmitting branch (DCS/PCS) and a branching circuit
are coupled to the terminal (11). The branching circuit comprises at
least a first and a second branch for receiving signals in first and
second frequency bands (DCS, PCS), respectively. Each of the first and
second branches comprise, respectively, a phase shifting circuit (PS1,
PS2), a BAW or SAW band pass filter (RXF2, RXF3) coupled to the phase
shifting circuit, the bandwidth of the filter being selected to pass a
wanted signal in one of the first and second frequency bands but reject
an unwanted signal in the other of the second and first frequency bands,
and a low noise amplifier (LNA2, LNA3) coupled to an output of the band
pass filter. The response of each of the band pass filters (RXF2, RXF3)
is phase shifted to present an open circuit at the wanted frequency in
the other branch. Each of the phase shifting circuits (PS1, PS2) is
impedance transforming so that higher impedance filters can be used.