A radio frequency (RF) system is provided. The RF system includes an RF transceiver, an RF processing circuit, a transfer switch module, a first antenna, a second antenna, a third antenna, and a fourth antenna. The RF transceiver is coupled with the RF processing circuit. The RF processing circuit is coupled with the transfer switch module. The transfer switch module is coupled with the first antenna, the second antenna, the third antenna, and the fourth antenna. When the RF system operates in a non-standalone (NSA) mode, the first antenna is configured for transmission in a first low band (LB) and primary reception in the first LB, the second antenna is configured for transmission in a second LB and primary reception in the second LB, the third antenna is configured for diversity reception in the second LB, and the fourth antenna is configured for diversity reception in the first LB.