MINIATURIZED ANTENNA DUPLEXER USING SAW FILTER

摘要

The invention disclosed is an antenna duplexer comprising a local oscillation filter, a reception filter, a transmission filter and an antenna. The reception filter is formed in two parts one of which is coupled with the local filter and the other of which is coupled with the transmission filter. The antenna is coupled to the junction of the reception filter and the transmission filter. The duplexer is unique in that the local filter and the one part of the reception filter are together formed as a surface acoustic wave (SAW) filter. The invention permits the use of SAW filters which can greatly reduce the overall size of the device while at the same time preventing burning which is a recognized problem with SAW filters.