RF/microwave power divider will split an input signal into two equal and identical (i.e. in-phase) signals. It can also be used as a power combiner, where the common port is the output and the two equal power ports are used as the inputs. Important specifications when used as a power divider include the insertion loss, amplitude and phase balance between the arms, and return losses. For power combining of uncorrelated signals, the most important specification is the isolation, which is the insertion loss from one equal power port to the other.