Adaptive ionic liquid polymer microwave modulation surface with reprogrammable dielectric properties

Abstract Adaptive microwave surfaces can dynamically tune their electromagnetic response to meet specific demands, offering significant value for the efficient integration and flexible application of electromagnetic devices in reconfigurable communication systems. In this work, we utilize temperature induced break and reconstruction of hydrogen bonds to drive the orientational motion and charge mobility of the ionic liquid [EtA⁺][NO₃⁻] in the PHEA, resulting significant and systematic modulation of dielectric properties at microwave frequencies. Based on this mechanism, we employed machine learning algorithms to design a reprogrammable dielectric microwave modulation surface. For example, the 2 mm-thick switchable microwave absorbing surfaces fabricated here can operate in two distinct modes, namely “off-to-on” and “on-to-off”. The corresponding tunable effective absorption bandwidths and reflection loss values reach 5.69 GHz, − 6.04 dB to − 46.21 dB, and 5.34 GHz, − 50.48 dB to − 6.47 dB, respectively. Using the developed active surface, we also demonstrate various 3D-printed device architectures, including pixelated surfaces, metasurfaces, and self-sensing functionalities, which provide valuable guidance for the development of next-generation intelligent electromagnetic devices.