None-radiative Method to Characterize Paper Substrates at mmWave

This paper used different lengths method to characterize paper substrate at mmWave. The contribution of dielectric loss, radiation loss, and ohmic loss are considered to obtain a precise loss tangent. Strip lines are used to reduce the radiation effect. The measurement results are verified by retro simulation. For demonstration, the 28 GHz band was considered. In experimental, the paper substrate presents a relative permittivity of ε r = 2.79 ± 0.14 from 26 GHz to 30 GHz. In this frequency band, the obtained loss tangent is tanδ = 0.093 ± 0.014 The relatively stable characteristics of paper substrate around 28 GHz demonstrate its potential applications in mmWave.