Duplexer with phase shifter circuit
A duplexer comprising an improved matching circuit for matching between transmitting path and receiving path is specified. In this case, the matching circuit comprises a hybrid and matching elements.
1. A duplexer, comprising:
an antenna port for receiving an RF input signal, a transmitting port, a first receiving port and a second receiving port;
a hybrid; a transmitting filter in a transmission signal path between the hybrid and the transmitting port; and
a first receiving filter in a first reception signal path between the hybrid and the first receiving port,
a second receiving filter in a second receiving path between the hydrid and the second receiving port,
wherein a matching element is interconnected between the transmitting port and the hybrid or between the receiving ports and the hybrid;
wherein the hybrid comprises a first, second, third and fourth port,
wherein the third port is interconnected with the antenna port,
wherein the second port and the fourth port are interconnected with the receiving ports, and
wherein the first port is an input port which is interconnected with the transmitting port and a phase difference between output signals of the second and fourth ports is approximately 180°.
2. The duplexer according to claim 1 , wherein the reception signal path is provided for balancing the output signals.
3. The duplexer according to claim 1 , further comprising the matching element between the transmitting port and the transmitting filter or between the transmitting filter and the hybrid.
4. The duplexer according to claim 1 , further comprising the matching element between the hybrid and the receiving filter or between the receiving filter and the receiving port.
5. The duplexer according to claim 1 , wherein the matching element is selected from: a capacitive element, an inductive element, or a stripline.
6. The duplexer according to claim 1 , wherein the transmitting filter or the receiving filter operates with surface acoustic waves, with bulk acoustic waves or with guided bulk acoustic waves.
7. The duplexer according to claim 1 , wherein the hybrid comprises coupled transformers.
8. The duplexer according to claim 7 , wherein a turn ratio of the coupled transformers is 0.5.
9. The duplexer according to claim 1 , wherein the antenna port has an impedance of 100Ω, the transmitting port has an impedance of 25Ω and the receiving ports have an impedance of 100 Ω.
10. The duplexer according to claim 1 , wherein the duplexer is configured for use in a mobile communication device.