Dynamically Continuous Tunable Metasurface With Switchable Transmission and Absorption Modes

The control of electromagnetic (EM) waves, especially over transmission, reflection, and absorption, is a cornerstone for advanced EM systems such as smart radomes and adaptive camouflage. However, achieving continuous control over these three responses within the same frequency band remains a significant challenge for active metasurfaces. Existing designs often suffer from discrete switching, narrow bandwidth, high insertion loss, and operating in separate bands. Therefore, this article proposes a novel active metasurface capable of dynamically and continuously regulating transmission and absorption responses in the same operational band. The metasurface comprises two key modules: an active frequency-selective layer and an active absorption layer. By biasing p-i-n diodes in their nonlinear region, the equivalent impedance of the absorption layer can be adjusted, enabling precise control over both the transmission loss and the ohmic loss. In the transmission-continuous-modulation mode, the EM response transitions from near-unity transmission to high reflection; in the absorption-continuous-modulation mode, transmission is suppressed, and reflection is tuned from perfect reflection to near-total absorption. Both simulations and measurements validate the metasurface’s performance, showing a wide −1dB transmission band and a broad −10 dB absorption band, with continuous tunability under bias voltage control. The proposed strategy offers a unified, low-profile, and versatile solution for developing next-generation adaptive EM systems.