1-Bit Terahertz Time-Space-Coding Metasurfaces with Refined Wavefront Modulation for Harmonic Beam Scanning Enhancement

Considering state of the art, coding-metasurface-based terahertz beam steering confronts issues of narrow angular range and low precision limited by nonideal space-encoded methodology. The emerging time-space coding metasurfaces open a new dimension to improve electromagnetic wave modulation accuracy and range under time-varying signal manipulation. Herein, based on the high electron mobility transistors (HEMTs), we propose a terahertz time-space coding metasurfaces (TTSCM) with refined wavefront modulation for harmonic beam scanning enhancement. Combining cyclic time modulations on the bias feeding signal and HEMT-switched phase coding, the TTSCM compensates the 1-bit quantization error with the joint coding for refined wavefront modulations. Numerical prediction verifies that the symmetrical ±1st harmonic beam scanning within ±80° angular range and a scanning accuracy of 1° has a larger field of view and higher precision. The proposed terahertz time-space-coding metasurfaces offers a feasible approach for various scenarios, such as super-resolution imaging and wireless communications.