Millimeter-Wave Absorbers with Printed Resistive Metasurface on Polymeric Substrate

In this paper, millimeter-wave absorbers are proposed for the WiGig communication frequency band (55–68 GHz) and a part of the 5G FR2 frequency band (22–44 GHz). Both proposed absorbers are designed to exhibit absorption performances greater than -10 dB at normal incidence and -8 dB at 45° oblique incidence within the frequency bands of interest. The absorbers feature a laminated structure composed of metasurfaces and polymeric substrates. The metasurfaces are fabricated by printing a conventional square-loop periodic pattern on polyimide film with resistive carbon ink using a screen-printing technique. The square-loop pattern is designed by accounting for the effect of the circuit linewidth of the printed square-loop pattern on the effective sheet resistance of its constituent circuit line. The absorbers are fabricated by attaching the metasurface print onto a polymer substrate and using copper film as a ground to the bottom. The performance of the fabricated millimeter-wave absorbers was verified using free-space measurement equipment, with the results confirming the achievement of the required absorption performance under normal and oblique incidences.