Transmit-and-receive module and communication device

A transmit-and-receive module comprising:

• a multiplexer comprising a common terminal, a transmit terminal, a receive terminal, at least one transmit filter, and at least one receive filter, wherein:
• the multiplexer is configured to receive an amplified radio-frequency transmit signal at the transmit terminal and output the amplified radio-frequency transmit signal from the common terminal, and to receive a radio-frequency receive signal at the common terminal and output the radio-frequency receive signal from the receive terminal,
• a pass band of the transmit filter is a transmit band of the transmit signal and a pass band of the receive filter is a receive band of the receive signal, and
• the transmit filter is connected between the common terminal and the transmit terminal, and the receive filter is connected between the common terminal and the receive terminal;
• a power amplifier configured to amplify the radio-frequency transmit signal and to output the amplified radio-frequency transmit signal to the transmit terminal;
• and
• a low-noise amplifier configured to amplify the radio-frequency receive signal received from the receive terminal, wherein:
• the power amplifier and the low-noise amplifier are integrated with each other,
• as graphed on a Smith chart, an impedance in the receive band of the receive filter as seen from the receive terminal intersects a line connecting a center point of noise figure circles and a center point of gain circles, the center point of the noise figure circles representing the impedance at which a noise figure of the low-noise amplifier is minimized and the center point of the gain circles representing the impedance at which gain of the low-noise amplifier is maximized,
• the multiplexer further comprises a second transmit terminal, a second receive terminal, a second transmit filter, and a second receive filter, the second transmit filter being connected between the second transmit terminal and the common terminal and the second receive filter being connected between the second receive terminal and the common terminal, and
• the transmit-and-receive module further comprises a transmit switch configured to selectively connect the transmit terminal or the second transmit terminal to the power amplifier, and a receive switch configured to selectively connect the receive terminal or the second receive terminal to the low-noise amplifier.