Real-frequency interpolation with positive-real n ports

A procedure is described for generating passive lumped nports that interpolate to prescribed n×n `passive¿ matrices at designated points on the real-frequency j¿ axis. In those cases where the given matrices are `lossless¿, the resulting n ports can be constructed with no more than 2qn reactive elements (q is the number of frequencies), whereas, in the general case, 4qn elements are used.