Power Distribution in Microwave Couplers

Analytical treatment is presented for lossy uniform and for tapered and chirped nonuniform couplers. Emphasis is placed on the coupling matrix and the transfer matrix of the coherency and Stokes vectors, which record the evolution of the power flow within the coupler. The interrelationships between these matrices are given and their eigenvalues and eigenvectors are evaluated. Criteria for power conservation, valid for codirectional as well as for contradirectional couplers are expressed in terms of system metrics.