Patent ID: 6122524
Filing Date: 2000-09-19
Classification: H04B

Abstract:
A user terminal for use in a communication system that includes a plurality of services provided on a plurality of frequencies, comprisinga common antenna through which the user terminal can selectively access each of said plurality of services, said common antenna being arranged to be matched at the frequency of at least one of said plurality of services;a selecting mechanism arranged to select between at least first and second operating modes, wherein, in said first operating mode said common antenna is operative as a matched antenna for at least one of said plurality of services, and in said second operating mode said common antenna is operative as an unmatched antenna for at least one other of said plurality of services;a tuning mechanism responsive to the selection of at least one other of said plurality of services, said tuning mechanism comprises an electrically controllable element for altering the frequency at which said common antenna is matched towards the frequency of said at least one other of said plurality of services; anda controller operative to monitor the amplitude of signals on said common antenna, said controller being operative to generate a control signal in response to the amplitude of the signals on said common antenna, said control signal being coupled as a controlling input to said electrically controllable element, and said electrically controllable element being responsive to said control signal to move the frequency at which said common antenna is matched towards the frequency of said at least one other of said plurality of services.