Joint Detections of Frequency and Direction of Arrival in Wideband Based on a Programmable Metasurface

Abstract

We propose a novel approach for achieving joint detections of frequency and direction of arrival (DoA) in wideband using a single sensor based on an active metasurface with programmable transmission states of pass and stop. By integrating two p-i-n diodes with the opposite directions into the proposed single-layer and ultrathin meta-atom, the transmission performance with 10 dB difference between the pass and stop states is realized in the bandwidth from 5.9 to 8.8 GHz using field-circuit cosimulations. Accordingly, random receiving patterns are generated by controlling the programmable metasurface composed of switchable meta-atoms. Afterward, the frequency and direction information of sources located in the far field is detected using the modified algorithm of estimating signal parameters via rotational invariance techniques (ESPRITs) and the compressive sensing method, respectively. A sample of the programmable metasurface is fabricated, and the voltage control system is built up correspondingly. To verify the proposed method’s validity, we conduct three typical categories of experiments: a single source, double sources with different frequencies, and double sources with the same frequency. In all cases, the source information of frequency and direction has been detected previously in measurements within the frequency band from 6.2 to 8.8 GHz.