Radio frequency circuit and mobile terminal

A radio frequency circuit comprising:

• a controller;
• and
• at least one duplexer coupled to the controller,
• wherein the duplexer comprises an impedance tuner coupled to the controller and at least one transceiver coupled to the impedance tuner,
• wherein the transceiver comprises a circulator, at least one radio frequency transmit path, at least one radio frequency receive path, a first directional coupler, and a second directional coupler,
• wherein the circulator comprises a first port coupled to the radio frequency transmit path, a second port coupled to the impedance tuner, and a third port coupled to the radio frequency receive path,
• wherein the first port, the second port, and the third port are arranged in sequence in a circular direction of the circulator,
• wherein the radio frequency transmit path is configured to:
• receive a first transmit signal;
• filter on the first transmit signal;
• and
• amplify the first transmit signal to obtain a second transmit signal,
• wherein the first directional coupler is configured to:
• receive the second transmit signal;
• use a part of the second transmit signal as a third transmit signal;
• directly send the third transmit signal to the circulator;
• and
• obtain, a first coupling signal from the second transmit signal,
• wherein the circulator is configured to:
• receive the third transmit signal through the first port;
• and
• output the third transmit signal through the second port,
• wherein the impedance tuner is configured to:
• transmit, to an antenna port, the third transmit signal;
• and
• transmit, to the second port of the circulator, a first input signal from the antenna port,
• wherein the circulator is further configured to:
• receive the first input signal through the second port;
• and
• send first input signal to the second directional coupler through the third port,
• wherein the second directional coupler is configured to:
• use a part of the first input signal as a second input signal;
• directly send the second input signal to the radio frequency receive path;
• and
• obtain a second coupling signal from the first input signal,
• wherein the radio frequency receive path is configured to filter on the second input signal to obtain a third input signal,
• wherein the circulator allows the radio frequency transmit path and the radio frequency receive path to work in duplex mode, and
• wherein the controller is configured to adjust impedance of the impedance tuner according to the first coupling signal and the second coupling signal so that impedance matching is achieved on the second port of the circulator.