Coupler talk - take 2 [Microwave Bytes]

In this paper, it is necessary to invert the phase of one of the signals to obtain the desired 100% power addition in the output coupler. Only in the equal power split case ( i.e., 3-dB couplers) can the same effect be obtained more conveniently by the reverse connection of the two equal power outputs; this property is, of course, widely used to make balanced amplifiers