  We propose to achieve joint detections of frequency and direction of arrival
in wideband using single sensor based on an active metasurface with
programmable transmission states of pass and stop. By integrating two PIN
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 GHz to 8.8 GHz
using field-circuit co-simulations. Accordingly, random receiving patterns are
generated by controlling the programmable metasurface composed of the
switchable meta-atoms. Afterwards, the frequency and direction information of
sources located in the far field are detected using the modified algorithm of
estimating signal parameters via rotational invariance techniques (ESPRIT) and
the compressive sensing method, respectively. A sample of the programmable
metasurface is fabricated and the voltage control system is built up
correspondingly. To entirely verify the validity of the proposed method, we
conduct three kinds of experiments with one single source, double sources with
different frequencies, and double sources with the same frequency,
respectively. In all cases, the source information of frequency and direction
has been detected preciously in measurements in the frequency band from 6.2 GHz
to 8.8 GHz.
