This disclosure relates generally to radio frequency (RF) front-end circuitry for different types of carrier aggregation, along with methods of operating the same. In one embodiment, the RF front-end circuitry includes a first diplexer, a second diplexer, first antenna selection circuitry, and second antenna selection circuitry. In order to maintain adequate isolation between high bands and low bands but provide carrier aggregation, the first antenna selection circuitry is configured to selectively couple each of a first plurality of RF ports to any one of a first low band port in the first diplexer and a second low band port in the second diplexer, while the second antenna selection circuitry is configured to selectively couple each of the second plurality of RF ports to any one of a first high band port in the first diplexer and a second high band port in the second diplexer.