Flexible Metasurface Lens for Vital Sign at 5.8 GHz Self-Injection Locked Radar

This paper presents a flexible transmitarray focusing electromagnetic waves beam in the far-field for healthcare radar. The flexible polyimide transmitarrray has a dielectric substrate of epsilon(r) = 3.5, tangent loss tan delta = 0.0027 and thickness = 152.4 mu m with transmission coefficient around 0.9. It comprises six dielectric substrates and four copper layers where the odd layers are printed with a circular and the even layers are printed with a cross. The proposed structure outperforms for remote detection in healthcare radar when evaluated with different focal lengths and bending conditions according to our knowledge of the most recent available publications.