Comments on “Design and Analysis of Swapped Port Coupler and Its Application in a Miniaturized Butler Matrix”

Supplementary solutions are provided for the swapped port coupler proposed by Jeong and Kim in the above paper. It is shown that the solution given in the above paper using uncoupled line section is not the only one for the coupler operation and a more generalized solution is presented through the extended analysis. The newly proposed solutions make it possible to design the swapped port coupler based on coupled lines with variable coupling coefficients or adjustable values of the lumped capacitor.