  As a widely used localization and sensing technique, radars will play an
important role in future wireless networks. However, the wireless channels
between the radar and the targets are passively adopted by traditional radars,
which limits the performance of target detection. To address this issue, we
propose to use the reconfigurable intelligent surface (RIS) to improve the
detection accuracy of radar systems due to its capability to customize channel
conditions by adjusting its phase shifts, which is referred to as MetaRadar. In
such a system, it is challenging to jointly optimize both radar waveforms and
RIS phase shifts in order to improve the multi-target detection performance. To
tackle this challenge, we design a waveform and phase shift optimization (WPSO)
algorithm to effectively solve the multi-target detection problem, and also
analyze the performance of the proposed MetaRadar scheme theoretically.
Simulation results show that the detection performance of the MetaRadar scheme
is significantly better than that of the traditional radar schemes.
