Patent ID: 8902021

Claim:
A Radio Frequency (RF) duplexer using Bulk Acoustic Wave Resonators (BAWRs), the RF duplexer comprising: a port converter configured to receive a signal from an antenna via a single-input port, to convert the received signal into a balance signal, and to output the balance signal via a dual-output port; and a BAWR receiving filter unit comprising an input end comprising a dual-input port to receive the balance signal from the dual-output port, and an output end comprising a dual-output port for dual output, wherein the BAWR receiving filter unit further comprises a ladder and a bridge, the bridge comprising: a first BAWR configured in series between a first input port of the dual-input port of the BAWR receiving filter unit and a first output port of the dual-output port of the BAWR receiving filter unit; a second BAWR configured in series between a second input port of the dual-input port of the BAWR receiving filter unit and a second output port of the dual-output port of the BAWR receiving filter unit; a third BAWR; a fourth BAWR; a first capacitor comprising a first end directly connected to an input end of the first BAWR, and a second end directly connected to a first end of the third BAWR; and a second capacitor comprising a first end directly connected to an output end of the first BAWR, and a second end directly connected to a first end of the fourth BAWR, wherein a second end of the third BAWR is directly connected to an output end of the second BAWR, and a second end of the fourth BAWR is directly connected to an input end of the second BAWR.