|Efficient Design of Contiguous-Band Elliptic-Response Manifold Output Multiplexers with Single-Terminated Filters
|Year of Publication
|Montejo-Garai, J. R., J. A. Ruiz-Cruz, and J. M. Rebollar
|H-plane, mode matching, transmission zero
|A procedure for the synthesis and design of contiguous-band manifold output multiplexers based on singly terminated filters with an elliptic response is presented. An extension of the Cauer ladder development using the zero-shifting technique leads to the synthesis of a driving-point impedance, including transmission zeros at finite real frequencies. The synthesized canonical forms have different topologies, number of reactive constant elements, and reactive part of the driving impedance, which have been compared to find the most suitable combination in the multiplexing process to match the channels to the manifold. The study proposed here is very important for improving the design process, and it is illustrated with four different multiplexer configurations and implemented with different pole-extraction orders in the ladder singly terminated filters. The multiplexer design has been divided into tasks with low computational effort extensively using the circuit model. Thus, the final full-wave optimization is significantly reduced, since the starting point is closer to the required specification. Finally, a Ku-band four-channel elliptic-response multiplexer has been designed in the H-plane rectangular waveguide, manufactured and measured in order to show the proposed approach.