A Novel High-Resolution Imaging Method Based on Nonlinear Wavefront Modulation

Radar can effectively conduct remote sensing detection, but antenna aperture limits the radar system’s azimuth resolution. Generally, the azimuth resolution of radar is the 3-dB beamwidth. To improve the azimuth resolution without changing the antenna aperture, we propose a high-resolution imaging method based on nonlinear wavefront modulation. The differences between the echo signals of different azimuth targets can be increased by applying multiple nonlinear modulations to the electromagnetic (EM) waves in different spatial directions. Then, we present an implementation of the nonlinear wavefront modulator. By changing the plasma state, valuable reference information can be provided for target imaging. Finally, experiments demonstrate the effectiveness of the proposed method. This is the first time a high-resolution imaging method based on plasma wavefront modulation has been reported. The measurement results demonstrate that the proposed method images three targets within a 3-dB beamwidth at the same antenna aperture.