A practical de‐embedding technique based on the network theory for the filters in a 2‐channel multiplexer

Abstract

Abstract A novel approach to de‐embed the frequency response of filters connected to a 2‐channel multiplexer without the need for unplugging is proposed. The technique to manifold coupled multiplexers with arbitrary number of filters is also theoretically generalised. In multiplexer tuning, there are practically important circumstances in which it is advantageous to de‐embed the frequency response of filters in multiplexers without detaching them. The authors show that using a novel technique and reasonable approximations, all filters of a multiplexer can be modelled by simple microwave networks, and then, the equivalent rational function of the channel filters can be estimated appropriately by the rational H2 approximation; extraction of this model facilitates tuning of the filters using the coupling matrix method. The impact of mechanical tolerances on the accuracy of the proposed technique is also studied. Next, this method is examined on a 2‐channel multiplexer and its application in de‐embedding and tuning of its connected filters is verified. Provided that the mechanical tolerances of the structure are sufficiently small, this technique is a powerful engineering solution towards tuning of manifold‐coupled multiplexers.

Keywords

• frequency response
• gradient methods
• manifolds
• matrix algebra
• multiplexing equipment
• transfer functions