An adjustable matching network is provided for a wireless communications device
transmitting and receiving signals in multiple frequency bands via an antenna.
The adjustable matching network selectively connecting the antenna to a select
power amplifier corresponding to a selected transmit frequency band and automatically
matching the impedance of the antenna to the select power amplifier. The adjustable
matching network also selectively connecting the antenna to a select bandpass filter
corresponding to a selected receive frequency band and automatically matching the
impedance of the antenna to the select bandpass filter.