Real-Time Near-Field mmWave Measurements Using Screen-Printed Metasurfaces and IR Camera

This article elaborates on a technique for rapid real-time imaging of millimeter-wave (mmWave) power density over surfaces of several wavelengths in size. The approach involves using a screen-printed metasurface equipped with elements designed for absorption of mmWaves, along with an infrared (IR) camera to monitor temperature changes due to the absorption. By modulating the transmitted signal and applying the metasurface technique, which concentrates absorbed power onto specific regions, we successfully detected typical mmWave power levels. This method provides an efficient, noncontact means of rapidly evaluating and characterizing devices emitting in the mmWave spectrum. To illustrate the efficacy of the technique, we present two case studies at 28 GHz: fault detection on a 256-element square array antenna in the Ka-band, and mmWave power density imaging in the near-field of a mobile phone mockup over surfaces measuring 58 square centimeters (51 square wavelengths at 28 GHz). The results obtained can be analyzed in both the time and frequency domains, augmenting comprehension and assessment capabilities.