Time-varying Polarization-converting Programmable Metasurface and Its Application in Wireless Communication System

We propose a general scheme to manipulate fundamental and harmonic frequencies simultaneously in a nonlinear fashion based on time-varying polarization-converting programmable metasurface. Co-polarization and cross-polarization reflection can be switched dynamically at an operating frequency of 2.4 GHz by loading metasurface with PIN (p-i-n) diodes. As a result, by adjusting a duty cycle and frequency of square-wave-type time-varying signals used for time-varying modulation, energy distribution and frequency shift in the frequency domain can be manipulated. To verify this, we fabricated a sample and conducted experiments, and the results agreed well with the theoretical prediction, confirming the design principle. Furthermore, we propose a wireless communication system based on binary amplitude-shift keying as an example of its practical application. The proposed one eliminates the need for complex device components on the emitter because the information is directly modulated onto the metasurface, greatly simplifying the traditional system. The proposed system can achieve a maximum transmission data rate of up to 625 kbps in experiments. The proposed metasurface paves a new way for time-varying manipulation of microwave and can have potential in real-world applications, such as next-generation communication and high-resolution imaging.