A photonics-based radar for high-resolution 3D microwave imaging is proposed and demonstrated, in which high range resolution is achieved by employing a wideband linearly frequency modulated signal, and high cross-range resolution in both azimuth and elevation is realized by rotating the target around two orthogonal axes to compose a 2D inverse synthetic aperture. The proposed radar performs photonics-based in-phase/quadrature up-conversion and de-chirp processing in the transmitter and receiver, respectively, which features a compact structure with low-sampling-rate electronics in the receiver. An experiment is carried out. The established radar works in the K-band, with bandwidth as large as 8 GHz. Captured echo signals at different rotation angles of the target are processed to a 3D image, in which the voxel values are scattering intensities at different spatial positions.
