A radio frequency, RF, system , comprising an RF transceiver , an RF processing circuit coupled with the RF transceiver , a transfer switch module , a first antenna , a second antenna , a third antenna , and a fourth antenna , wherein the RF processing circuit comprises a first transmit, TX, module , a second TX module , a first receive, RX, module , a second RX module , a first duplexer , a second duplexer , and a filtering module ; the first TX module is coupled with the transfer switch module through the first duplexer , the second TX module is coupled with the transfer switch module , the first RX module has a first RX port coupled with the transfer switch module through the first duplexer , the first RX module has a second RX port coupled with the transfer switch module through the second duplexer and the second TX module , the first RX module has a third RX port coupled with the transfer switch module through the second TX module , the second RX module has a first RX port coupled with the transfer switch module , the second RX module has a second RX port coupled with the third antenna through the transfer switch module or through the filtering module ; the first antenna and the second antenna are coupled with the transfer switch module , the third antenna is coupled with the transfer switch module or the filtering module , and the fourth antenna is coupled with the transfer switch module or the filtering module , wherein antenna efficiency of the first antenna and the second antenna is higher than that of the third antenna and the fourth antenna ; and the first antenna is used for transmission in a first low-band, LB, and primary reception in the first LB, the second antenna is used for transmission in a second LB and primary reception in the second LB, the third antenna is used for diversity reception in the second LB, the fourth antenna is used for diversity reception in the first LB, and the filtering module is configured to filter out bands other than the first LB, when the RF system works in a non-standalone, NSA, mode. the RF processing circuit comprises a first transmit, TX, module , a second TX module , a first receive, RX, module , a second RX module , a first duplexer , a second duplexer , and a filtering module ; the first TX module is coupled with the transfer switch module through the first duplexer , the second TX module is coupled with the transfer switch module , the first RX module has a first RX port coupled with the transfer switch module through the first duplexer , the first RX module has a second RX port coupled with the transfer switch module through the second duplexer and the second TX module , the first RX module has a third RX port coupled with the transfer switch module through the second TX module , the second RX module has a first RX port coupled with the transfer switch module , the second RX module has a second RX port coupled with the third antenna through the transfer switch module or through the filtering module ; the first antenna and the second antenna are coupled with the transfer switch module , the third antenna is coupled with the transfer switch module or the filtering module , and the fourth antenna is coupled with the transfer switch module or the filtering module , wherein antenna efficiency of the first antenna and the second antenna is higher than that of the third antenna and the fourth antenna ; and the first antenna is used for transmission in a first low-band, LB, and primary reception in the first LB, the second antenna is used for transmission in a second LB and primary reception in the second LB, the third antenna is used for diversity reception in the second LB, the fourth antenna is used for diversity reception in the first LB, and the filtering module is configured to filter out bands other than the first LB, when the RF system works in a non-standalone, NSA, mode. <EOS>