Radio frequency circuit and mobile terminal

Abstract

The present invention provides a radio frequency circuit. In the circuit, a first directional coupler receives a second transmit signal, uses a part of the second transmit signal as a third transmit signal, directly sends the third transmit signal to a first port of a circulator, and obtains a first coupling signal from the second transmit signal; the circulator outputs the third transmit signal through a second port; an impedance tuner transmits the third transmit signal to an antenna port and transmits, to the second port of the circulator, a first input signal from the antenna port; the circulator inputs the first input signal to a second directional coupler through a third port; the second directional coupler obtains a second coupling signal from the first input signal; and a controller adjusts impedance of the impedance tuner according to the first coupling signal and the second coupling signal.

Description

technical field [0001] The present invention relates to the communication field, and more specifically, to a radio frequency circuit and a mobile terminal. Background technique [0002] In a frequency division duplex (Frequency Division Duplexing, FDD) system, the general duplex scheme can be as follows: Surface Acoustic Wave (SurfaceAcousticWave, SAW) / body The acoustic wave (BulkAcousticWave, BAW) process realizes the resonant filter. On the one hand, these two filters are used as the TX / RX bandpass filter of the radio frequency circuit, and on the other hand, they also provide TX-RX isolation. These two filters are at the antenna port Coupled together through an impedance matching circuit. However, the main disadvantage of the above-mentioned duplex scheme is that the TX / RX channel filtering and duplex functions are coupled together, and the operating frequency bands of the SAW / BAW resonant filter and the impedance matching circuit are both narrow-band, so the supported f...

AI Technical Summary

Problems solved by technology

However, the main disadvantage of the above-mentioned duplex scheme is that the TX/RX channel filtering and duplex functions are coupled together, and the operating frequency bands of the SAW/BAW resonant filter and the impedance matching circuit are both narrow-band, so the supported frequency range is small and the frequency band is fixed It cannot be tuned. If you need to support multi-mode and multi-frequency, you need multiple sets of the above-mentioned duplexers

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