Loss Evaluation of Microstrip Line Using Low-Loss Olefin-Based Resin Build-Up Film in 160-GHz Band

A new film material, MW300, that is both compatible with build-up processes and capable of maintaining low dielectric loss, has been developed. Measurements of the dielectric properties of MW300 in the subterahertz band exhibited a loss tangent, tan $\delta $ of 0.0022 at 160 GHz, demonstrating lower loss compared to conventional build-up compatible organic materials. Analysis of the transmission loss in microstrip lines (MSLs) indicated that dielectric loss is more dominant than conductor loss in the subterahertz region, suggesting that using low-dielectric-loss materials is effective in reducing transmission loss. MSLs were fabricated on build-up substrates using both conventional materials and MW300. Measurements of the transmission loss confirmed the analytical predictions. The MSL using MW300 achieved a low-loss measurement result of 0.10 dB/mm in the 160-GHz band.