Transmission-Reflection-Integrated Programmable Metasurface for Simultaneous and Independent Control of Bidirectional Incident Waves

Abstract

The flexible control of electromagnetic (EM) waves across the entire spatial domain is a long-standing aspiration in metasurface research, driven by its potential to enhance signal coverage and channel capacity. However, most existing full-space metasurfaces are restricted to manipulating incidence within one specific half-space, failing to exploit the EM potential across the entire space. This paper introduces a novel bidirectional transmission-reflection-integrated metasurface (BTRIM) for simultaneous and independent control of full-space incident waves. By dynamically adjusting diode states, the BTRIM can switch among simultaneous and independent forward/backward reflection, forward transmission-reflection (TR), and backward TR functions, each with an independent 1-bit phase response. The core innovation lies in integrating transmission and reflection within a single structure, enabling the metasurface to function at the same frequency and polarization within a compact design. Simulations and experimental validation are conducted to demonstrate BTRIM's ability to implement various wave functions and enhance signal intensity for users in both indoor and outdoor environments. The agreement between simulation and experimental results validates the BTRIM's capacity to simultaneously and independently regulate EM waves from all spatial directions, offering new insights into full-space wave manipulation. This breakthrough creates opportunities for applications in EM sensing, channel enhancement, and next-generation communication systems.