Duplexer with improved transmission/receiving band separation

The invention relates to a duplexer for a wireless communication system with a transmission band and a receiving band. According to the invention, a split surface wave filter consisting of at least two partial filters which cover adjacent partial frequency ranges of the corresponding band and which together form an entire band, is provided as an input and/or output filter. At least two pairs of partial filters are provided, each pair comprising a filter in the input and output filter respectively. A switch is used to switch between the at least two pairs. If the duplexer interval remains the same, a greater band interval is created between the transmission and receiving bands or between the corresponding partial frequency ranges, said band interval being produced with surface wave filters.