Effective Conductivity of Additive-Manufactured Metals for Microwave Feed Components

This paper characterizes the effective conductivity of lossy metal materials fabricated with additive manufacturing processes at microwave frequencies using a resonant cavity approach. Specifically addressed is the powder bed fusion additive manufacturing process utilizing AlSi10Mg material at Ku-band. The details of the procedure for converting device parameters that characterize the resonant cavity to material properties are given. Trade-offs between the precision of the conductivity and the quality factor of the cavity are discussed relevant to the design of the cavity. A best-fit matching procedure is made between the measured response of the manufactured cavities and the simulated results. The conductivity with statistical deviation for various fabricated cavities from different vendors is reported. Examples of various designs of fabricated prototype waveguide feed components are presented. The predicted and measured performance of each component is compared, validating the process.