  Conventional multistatic radar systems using microwave and millimeter-wave
(mm-wave) frequencies seek to reconstruct the target in the imaging domain,
employing many transmitting and receiving antenna elements. These systems are
suboptimal, in that they do not take into consideration the large mutual
information existing between the measurements. This work reports a new mm-wave
radar system for high sensing capacity applications. The system is composed of
a Compressive Reflector Antenna (CRA), whose surface is specially tailored by
digitized Metamaterial Absorbers (MMAs). The MMA elements are designed to have
a highly frequency-dispersive response in the operating band of the radar. This
enables the CRA to create highly uncorrelated spatial and spectral codes in the
imaging region. A semi-analytic method based on Drude-Lorentz model is used to
approximate the reflection response of the MMAs. The performance of the
developed radar system is evaluated in active mm-wave sensing systems by
imaging PEC scatterers and an extended human-size model in the near-field of
the radar. A computational method based on physical optics is established for
solving the numerical examples. For reconstructing the image using compressive
sensing techniques, a norm-1 regularized iterative algorithm based on the
Alternating Direction Method of Multipliers (ADMM) and a Nesterov-based
algorithm (NESTA) were applied.
