We present a sparse synthetic aperture system at W-Band (75 – 110 GHz) using sub-harmonic mixer modules. The active system consists of a scanned transmitter module, a fixed receiver module and a vector network analyzer as the back end. For this scanned synthetic aperture system we construct a complete analytical forward model and solve the inverse problem to reconstruct the scene using least squares technique. We demonstrate standoff diffraction limited imaging of 2D and 3D targets and achieve a cross range resolution of 3 mm and a depth range resolution of 4 mm respectively. Furthermore, we also show that the positions of the transmitter can be further optimized using finely gridded scattered electric field information from a specific target. This optimization technique helps to reduce the number of measurements significantly by using measurements above a certain threshold SNR for the scene reconstruction.
© 2015 Optical Society of AmericaPDF Article