Duplexer using surface acoustic wave (SAW) band-pass filter chips e.g. for portable communication devices

摘要

The duplexer features a multilayer ceramic package (32) enclosing a number of chips (33a,33b) with passbands centred at different frequencies. A phase-matching circuit pattern (37a-37c) on the surface of the package comprises two meander-line conductors of e.g. Cu and a connection strip continuous with an antenna connection (36c). Earthing patterns (GND) are formed on the undersides of alternate layers (321,323). The intermediate layer (322) carries signal patterns connected to the chips by wire bonds (34), and the final layer (324) has connections (36a,36b) for reception and transmission respectively.