Wideband Radiation-Type Programmable Metasurface-Enabled High-Precision Beam Modulating for IoT Applications

Programmable metasurfaces promise a great potential to construct low-cost phased array systems due to their capability of elaborate control over electromagnetic waves for Internet of Things (IoT) applications. However, they are usually in either reflective or transmissive scheme, and possess a relatively high profile as a result of the external feed source. Besides, the phase resolution is insufficient comparing with conventional phased array antennas. In this article, we propose a low-profile wideband radiation-type programmable metasurface and further present the high-precision beam modulating for IoT applications. It could avoid the external space-feed source required by its traditional counterpart, thus achieving a significant reduction of profile height through integration of a high-efficiency microwave excitation network and metasurface radiators. Furthermore, high-precision amplitude-phase weight algorithm was then synchronously carried out for low side-lobe beam scanning through time-coding sequences modulation strategy. Experimental results illustrate that our programmable metasurface could obtain a peak gain of 20.6 dBi at 5.5 GHz with reduced sidelobe level of lower than -23 dB.