RF front end circuitry includes a first antenna node, a second antenna node, a diplexer, a first band filter, a second band filter, and switching circuitry. The diplexer may be used to separate signals for carrier aggregation, providing signals within a first RF frequency band to the first band filter and signals within a second RF frequency band to the second band filter. Further, by strategically arranging the switching circuitry, the diplexer may also be used as a multiple-input-multiple-output filter, such that additional filters are not required to support one or more MIMO modes of the RF front end circuitry.