  The use of automotive radars is gaining popularity as a means to enhance a
vehicle's sensing capabilities. However, these radars can suffer from
interference caused by transmissions from other radars mounted on nearby
vehicles. To address this issue, we investigate the use of an onboard
intelligent reflective surface (IRS) to artificially increase a vehicle's
effective radar cross section (RCS), or its "electromagnetic visibility." Our
proposed method utilizes the IRS's ability to form a coherent reflection of the
incident radar waveform back towards the source radar, thereby improving radar
performance under interference. We evaluated both passive and active IRS
options. Passive IRS, which does not support reflection amplification, was
found to be counter-productive and actually decreased the vehicle's effective
RCS instead of enhancing it. In contrast, active IRS, which can amplify the
reflection power of individual elements, effectively combats all types of
automotive radar interference when the reflective elements are configured with
a 15-35 dB reflection gain.
