Effect of the Alumina Particle Filler Structure and Particle Size on the Dielectric Constant and Dielectric Loss in the Millimeter-Wave Band.

The sixth-generation communication system (6G) is the next-generation communication system and is expected to be operational in 2030. The following areas will use 6G: the frequency band employed in 6G is expected to be 100 GHz or higher, necessitating additional reduction of the dielectric constant and dielectric loss in the substrate material. In this study, we examined the effects of compounding various phases of alumina with different shapes and crystal phases on the dielectric constant and dielectric loss of cyclo-olefin polymer (COP) compounds. It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. The dielectric loss decreased from 1.6 × 10 -3 of COP to 1.2 × 10 -3 when the smallest filler was added at 30 wt %.