Design of Electromagnetic Wave Absorption Sheet with Transparency and Flexibility in sub-THz Bands

This paper reports on improvements achieved in the development of an electromagnetic wave absorption sheet. Drastic improvements have been made to the flexibility, light transmittance and absorption of electromagnetic waves in millimeter-wave and sub-THz bands. The design parameter of the EM-wave absorption sheet has been adjusted to a set reflection decrement of −20 dB aim with the target frequency of 250 GHz by a two-dimensional simulation based on the reflective theory of EM-wave. Samples of this improved EM-wave absorption sheet have now been successfully manufactured. The transparency level of the EM-wave absorption sheet sample is 62.3%. After flexibility testing, microphotographs show no cracks in the surface of the resistive layer where the EM-wave absorption sheet sample was bent by diameter 0.5 mm. The EM-wave absorption performance results of both the 2D simulation and actual product sample were very similar.