Discussions on microwave measurement of permittivity anisotropy in the plane of dielectric laminate substrates

This paper proposes a method to measure permittivity anisotropy in the plane of dielectric laminate substrates by utilizing orthogonality of TE₁₁₁ mode in a circular cavity resonator. For cyclo-olefin polymer (COP), liquid crystal polymer (LCP) and glass cloth PTFE substrates, the permittivity anisotropy in the plane is measured by this method. As a result, usefulness of this method is verified by the measured results of these three samples.