An enhanced optimization technique for design of tune-free diplexers

An approach is proposed that allows computationally efficient optimization of tune-free diplexers. Following the proposed technique the diplexer channels are virtually decoupled making their joint electromagnetic optimization unnecessary. In practice this is realized by using especially constructed resonance-type boundary that allows one to replace any chosen channel during EM optimization. Since the latter is computationally expensive part of the diplexer design, one achieves considerable improvement of the efficiency due to reduced size of the computational domain. To demonstrate the accuracy and high practical value of the approach, a diplexer in E-plane technology is designed, fabricated and experimentally verified. Although the discussion in this work is limited by diplexers only, the proposed technique can be extended to design of tune-free multiplexers.