Controllable Reflection-Enhancement Metasurfaces via Amplification Excitation of Transistor Circuit

This study proposes a novel controllable reflection-enhancement metasurface (CREM) design method to amplify electromagnetic (EM) signals in a reflective manner. In contrast to previous passive structures, a field-effect transistor (FET) amplification circuit is integrated into the unit cell of a reflective metasurface. The FET circuit amplification shows that the metasurface can magnify the reflected wave intensity. A CREM composed of FET-connected dual-patch unit cells is designed for the specific implementation of the proposed method. The simulation and experimental results indicate that an apparent gain can be achieved in the operating band. Moreover, the reflection coefficient can be edited as required by the amplification level of the FET circuit. The tunable range of the reflection amplitude is approximately 10 dB. Different from the traditional signal amplifier, signal amplification is achieved herein in a reflective manner, which simplifies the amplification process and provides a new method of controlling EM waves. Our work provides an effective route to reflection enhancement and enables the design of devices and systems for real-world applications on demand.