Composite filter and communication device

A composite filter that performs at least one of a process of simultaneously inputting two signals having different frequencies within a first passband to a first terminal and a process of simultaneously inputting two signals having different frequencies within a second passband to a second terminal, the composite filter comprising:

• a common terminal;
• the first terminal;
• the second terminal;
• a first filter system connecting the common terminal and the first terminal to each other;
• a second filter system connecting the common terminal and the second terminal to each other;
• and
• a first 90° hybrid coupler connected to the common terminal that is shared by the first filter system and the second filter system, wherein the first 90° hybrid coupler comprises a first port that is connected to the common terminal, a second port, a third port electrically connected to the first port and the second port, and a fourth port electrically connected to the first port and the second port, the fourth port being a port to which a signal with a phase shifted by 90° relative to a phase of a signal distributed from the first port to the third port is distributed from the first port,
• wherein the first filter system comprises:
• a first filter connected to the third port and corresponding to the first passband;
• a second filter connected to the fourth port and corresponding to the first passband;
• and
• a second 90° hybrid coupler connecting the first filter and the second filter to the first terminal,
• wherein the second 90° hybrid coupler comprises:
• a fifth port,
• a sixth port,
• a seventh port electrically connected to the fifth port that is connected to the first filter and the sixth port that is connected to the second filter, and
• an eighth port electrically connected to the fifth port, the sixth port and the first terminal, the eighth port being a port to which a signal with a phase shifted by 90° relative to a phase of a signal distributed from the fifth port to the seventh port is distributed from the fifth port,
• wherein the second filter system electrically connects the third port and the fourth port to the second terminal and relatively shifts a phase of a signal flowing from the third port toward the second terminal by 90° relative to a phase of a signal flowing from the fourth port toward the second terminal to change a phase difference between the two signals by 90°
• wherein the second filter system comprises:
• a third filter connected to the third port and corresponding to the second passband,
• a fourth filter connected to the fourth port and corresponding to the second passband, and
• a third 90° hybrid coupler connecting the third filter and the fourth filter to the second terminal,
• wherein third 90° hybrid coupler comprises:
• a ninth port that is connected to the third filter,
• a tenth port that is connected to the fourth filter,
• an eleventh port electrically connected to the ninth port and the tenth port, and
• a twelfth port electrically connected to the ninth port, the tenth port and the second terminal, the twelfth port being a port to which a signal with a phase shifted by 90° relative to a phase of a signal distributed from the ninth port to the eleventh port is distributed from the ninth port.