Automated Diplexer Design With Key Performance Indicator-Based Objectives

Microwave diplexers are often designed iteratively via manual channel-by-channel or resonator-by-resonator local optimization procedures due to high dimensionality in design variables and the complexity of structures. A one-off automated diplexer optimization method is yet to be developed. To achieve this, other than improved optimizers, an effective objective function (OF) is critical to allow optimizers to find the desired designs. This letter realizes an automated diplexer design by proposing key performance indicator (KPI)-based objectives. The KPIs are extracted from
$S$
-parameter responses. An all-resonator diplexer with 22 variables and a Tee-junction diplexer with 23 variables are designed using the proposed method via one-off optimization, showing 100% and 80% success rates, respectively.