Synthesis of Distributed Elliptic-Function Filters from Lumped-Constant Prototypes

Filters based on the elliptic-function or Cauer-parameter type of response give rapid cut-off compared with filter responses of Chebychev or Butterworth types which have no attenuation poles at finite frequencies. The response of a distributed band-stop filter consisting of commensurate lengths of transmission line, based on a two-pole lumped element prototype, is shown in Fig. 1 as an example of the type of response desired.