Direction Matters: Including Substrate Anisotropy in Planar Circuit Design Flow

摘要

In the late 1970s, when one of the authors (Rautio) first got started in microwaves, one of his first tasks was to design filters on alumina for Landsat IV. The design was carefully performed using the commonly assumed substrate dielectric constant of 9.8. Even so, several design iterations were required. "Get used to it," he was told. "Multiple design iterations are a fact of microwave design life." Or so it was thought.