Tunable Band-Gap for Metallic Packages and Cavities

The paper proposes a novel topology of metallic cavities and packages that is able to provide a tunable bandgap for inhibiting cavity resonances and thus for reducing the electromagnetic interference within the cavity. The cavity top lid needs to include metallic pins. The bandgap principle relies on the creation of an artificial Perfect Magnetic Conductor (PMC) surface at the pin bottom face; the PMC surface is generated within a well-defined range of frequency that depends on the pin geometry and other cavity dimensions. The bandgap tunability proposed herein is achieved by mechanically tuning the pin length. A sample is manufactured and experimental measurements are provided to demonstrate the reliability of the proposed technique. Analytical expressions previously developed are refined to predict more accurately the bandgap frequencies, and they are validated by both full-wave simulations and measured results.