Dielectric Characterization of Adhesives for THz Packaging in WR6.5, WR3.4 and WR2.2 Bands

This study presents, for the first time to our knowl-edge, measurements of permittivity and loss tangent ranging from 110 GHz to 500 GHz for technical adhesives. Measurements were conducted using the material characterization kits by Swissto12. To ensure a high accuracy, the samples were carefully prepared to achieve optimal surface parallelism, since any deviation in thickness measurement directly affects the derived values of per-mittivity and loss tangent. For validation purposes, we measured reference materials and benchmarked our findings against in-dependent research, proving the precision of our measurements. Our observations showed nearly constant permittivity in the WR 6.5, WR 3.4, and WR 2.2 bands for all adhesives. Specifically, for UV adhesives NEA 121 and NEA 123M, as well as the single-component epoxy EP501, a permittivity of 3.0 was identified, while for the two-component epoxy Duralco 4460, an
^ε
r of 2.8 was determined.