Analysis of the variable-ratio microwave power divider (Correspondence)

It has been shown experimentally that a variable-ratio microwave power divider is easily assembled from two identical 3-db directional couplers and a phase changer. The scattering matrix of this structure is readily obtained from the flow graph showing the interconnections between the couplers. The following shows that the whole structure is still a directional coupler, derives the conditions to optimize the power transfer, and finally, gives the phase angles of the scattering coefficients.