A mobile communication device, preferably in the form of a dual-band cellular
phone,
includes two communications systems supporting different frequency bands, such
as DCS in the 1.8 GHz band and GSM in the 900 MHz band. The mobile communication
device includes an antenna, a high-frequency composite unit, DCS and GSM transmitters,
and DCS and GSM receivers. The high-frequency composite unit contains a diplexer,
DCS and GSM high-frequency switches, DCS and GSM high-frequency filters or notch
filters, and a directional coupler.
