Patent ID: 6249687
Filing Date: 2001-06-19
Classification: H01P,H04B

Abstract:
A mobile phone (1) for at least two frequency bands (5, 10), said mobile phone comprising an antenna (20) coupled to a multiplex type filter (25),wherein the multiplex type filter (25) comprises at least two disparate bandpass filters (30, 35) for either separate reception or separate transmission frequency bands (5, 10), said at least two disparate bandpass filters (30, 35) including a first bandpass filter (30) having as a passband a first frequency band (5) and a second bandpass filter (35) having as a passband a second frequency band (10), an input impedance of the first bandpass filter (30) in the second frequency band (10) is higher than an input impedance of the second bandpass filter (35) in the second frequency band (10) and an input impedance of the second bandpass filter (35) in the first frequency band (5) is higher than an input impedance of the first bandpass filter (30) in the first frequency band (5);whereby coupling of signal power at frequencies in the first frequency band (5) to the second bandpass filter (35) and coupling of signal power at frequencies in the second frequency band (10) to the first bandpass filter (30) is substantially reduced.