High- $Q$ Resonators and Filters Inside Advanced Low-Temperature Co-Fired Ceramic Substrates Using Fine-Scale Periodicity

Effective media are shown to be created by patterning a material to overcome inherent material losses. Two different types of effective media, i.e., the windowpane and stratified media formed by fine-scale periodicity, are investigated. The effect of different perforations in the material is demonstrated. In particular, a great reduction in dielectric loss is observed in the stratified medium, making high-Q resonators and filters possible out of relatively lossy materials. Low-temperature co-fired ceramic (LTCC) fabrication can form advanced metamaterial substrates by realizing these two layer-by-layer effective media. High-Q (unloaded quality factors up to 762) resonators are demonstrated using the stratified medium concept, which reduces the dielectric loss by roughly 50%. Two-pole filters at AT-band are measured to have insertions losses as low as 0.47 dB with 8.5% bandwidth. The demonstrated unloaded Q factor is much larger than that of a homogenous LTCC resonator, which is limited to an unloaded Q factor of approximately 400.