DUPLEXER, MODULE INCLUDING A DUPLEXER AND COMMUNICATION APPARATUS

• US 20100148886A1
• Filed: 02/24/2010
• Published: 06/17/2010
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Original Assignee: Fujitsu Limited
• Inventors: Tsutsumi, Jun, Inoue, Shogo
• Granted Patent: US 8,022,787 B2
• Time in Patent Office: Days
• US Class Current: 333/132
• CPC Class Codes: H01P 1/213 combining or separating two or more different frequencies H01P1/215 takes precedence
• CPC Class Codes: H01P 5/227 90° branch line couplers
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence
• CPC Class Codes: H03H 7/463 Duplexers
• CPC Class Codes: H03H 7/48 Networks for connecting several sources or loads, working on the same frequency or frequency band, to a common load or source phase shifters providing two or more output signals H03H7/21
• CPC Class Codes: H03H 9/0028 using surface acoustic wave devices
• CPC Class Codes: H03H 9/6483 Ladder SAW filters
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

A duplexer includes a common terminal, receiving filters, a transmitting filter, and a hybrid having four terminals (terminals 1 to 4). A first terminal (terminal 1), which is one of the four terminals of the hybrid is connected to the common terminal, the receiving filters are connected to a second terminal and a third terminal to which a signal is transmitted if it is input from the first terminal, and a transmitting filter is connected to a fourth terminal (terminal 4) of the hybrid. Thus, it is possible to improve the isolation of the duplexer, while avoiding an increase in the number of parts as well as greater complexity.

Claims

1. A duplexer comprising:

a receiving filter or receiving filters that let(s) a reception signal in a receiving band pass;

a transmission signal terminal into which a transmission signal in a transmitting band that is different from the receiving band can be input;

a common terminal with which input of the reception signal in the receiving band and output of the transmission signal in the transmitting band can be performed;

a hybrid that has a plurality of first terminals and a plurality of second terminals, and that splits a signal that is input from one of the first terminals with a phase difference and outputs the split signals to the second terminals;

wherein the common terminal and the transmission signal terminal are respectively connected to the first terminals; and

wherein the receiving filter(s) is/are connected to the second terminals.

2. The duplexer according to claim 1,

wherein the hybrid outputs split signals that is input from one of the first terminals and is split with a phase difference of 90°

to the second terminals, and

wherein the duplexer further comprises a phase shifter that shifts the phase of at least one of the reception signals that is input from the common terminal to the hybrid and is output with a phase difference of 90°

from the second terminals, setting said phase difference to 180°

.

3. The duplexer according to claim 1,

further comprising a second hybrid having a plurality of first terminals and a plurality of second terminals, splitting a signal that is input from one of the first terminals with a phase difference and outputting the split signals to the second terminals;

wherein the second terminals of said hybrid and the first terminals of the second hybrid are connected to each other via said receiving filter(s), and one of the remaining second terminals of the second hybrid is connected to a termination resistor;

the termination resistor is connected to the second terminal of the second hybrid to which transmission signals that are input from the transmission signal terminal into one of the first terminals of said hybrid and are respectively output with a phase difference from the second terminals of said hybrid, pass through the receiving filter, and respectively enter the first terminals of the second hybrid are transmitted with the same phase.

4. The duplexer according to claim 1,

wherein the hybrid is constituted by integrated passive devices;

and

these integrated passive devices, the receiving filter(s) and a transmitting filter are mounted on the same substrate.

5. A module comprising the duplexer according to claim 1.

6. A communication device comprising the duplexer according to claim 1.