Solution to the approximation problem for a class of 2-variable resonant ladder networks

By using the results on explicit formulas for element values in 1-variable ladder networks dependent on one or two auxiliary parameters, and by using appropriate frequency transformations, certain generalisations may be made to 2-variable networks. For the solution to the approximation problem, which results in an elliptic function or Cheby¿shev response, nonreciprocal 2-variable networks result, but for the matched inverse-Cheby¿shev-response case, a simple 2-variable ladder network is obtained. This case is treated in detail, and typical responses for networks containing lumped and commensurate distributed elements are presented, with a specific example on a waveguide bandstop filter.