RF front-end circuitry, which includes RF switching and duplexing circuitry, a first RF diplexer, and a second RF diplexer, is disclosed. The RF switching and duplexing circuitry operates in one of a group of RF transmit modes, such that the group of RF transmit modes includes at least one transmit uplink carrier aggregation mode. The RF switching and duplexing circuitry provides at least one RF transmit signal based on the one of the group of RF transmit modes. The first RF diplexer is coupled between the RF switching and duplexing circuitry and a primary RF antenna. The second RF diplexer is coupled between the RF switching and duplexing circuitry and an auxiliary RF antenna.