Front-end circuit, diversity circuit, and communication device

A front-end circuit comprising:

• a primary circuit configured to simultaneously transmit a first radio frequency signal in a first communication band and a second radio frequency signal in a second communication band, and configured to receive the first radio frequency signal and the second radio frequency signal;
• and
• a diversity circuit configured to receive a third radio frequency signal in the first communication band in response to reception of the first radio frequency signal in the primary circuit, and configured to receive a fourth radio frequency signal in the second communication band in response to reception of the second radio frequency signal in the primary circuit, wherein:
• the primary circuit comprises:
• a first input/output terminal, a first reception terminal, a second reception terminal, and a second transmission terminal;
• a first signal path connecting the first input/output terminal and the first reception terminal, and configured to pass the first radio frequency signal;
• and
• a second signal path connecting the first input/output terminal, the second reception terminal, and the second transmission terminal, and configured to pass the second radio frequency signal,
• in the second signal path, reception of the second radio frequency signal from the first input/output terminal to the second reception terminal, and transmission of the second radio frequency signal from the second transmission terminal to the first input/output terminal, are performed by time division duplexing,
• the diversity circuit comprises:
• a first input terminal, a third reception terminal and a fourth reception terminal,
• a first switch comprising a first selection terminal, a second selection terminal, and a first common terminal, the first common terminal being connected to the first input terminal, and the first switch being configured to selectively connect the first common terminal to the first selection terminal and to the second selection terminal,
• a first reception path connecting the first selection terminal and the third reception terminal, and configured to pass the third radio frequency signal from the first input terminal to the third reception terminal via the first selection terminal, and
• a second reception path connecting the second selection terminal and the fourth reception terminal, and configured to pass the fourth radio frequency signal from the first input terminal to the fourth reception terminal via the second selection terminal,
• when the first radio frequency signal in the first signal path is simultaneously received with reception of the second radio frequency signal in the second signal path, the first switch is configured to connect the first common terminal to the first selection terminal and to the second selection terminal, and
• when the first radio frequency signal in the first signal path is received simultaneously with transmission of the second radio frequency signal in the second signal path, the first switch is configured to connect the first common terminal to the first selection terminal and to the second selection terminal,
• wherein the first switch is not connected to the primary circuit.