Modeling of 3-D-Printed Helical-Microstrip Transmission Lines for RF Applications

This article presents a detailed analysis of the electrical performances of 3-D-printed helical-microstrip transmission lines. The transmission properties of these lines are studied theoretically. As a result, a model is proposed that consists of closed formulae for determining the characteristic impedance and the electrical length of the helical-microstrip transmission lines, as a function of electromagnetic parameters of the 3-D-printing base material and the geometry of the component. We also used the model to study the limits of compaction related to the helical geometry. The accuracy of the model is validated via finite-element method simulations and experimental results.