A wireless communications circuit includes: a transceiver; a power amplifier module including a plurality of power amplifiers coupled to the transceiver; a filter module, including a plurality of filters coupled to the power amplifier module; an antenna switching module coupled between the filter module and an antenna; a tunable matching network coupled between the antenna and the antenna switching module; and a baseband circuit coupled to the tunable matching network. The baseband circuit is used for generating a control signal to the tunable matching network to adjust an impedance of the tunable matching network, wherein the impedance of the tunable matching network is adjusted to be different values under different operating conditions of the wireless communications circuit.