We present results for a rapid, precise, and wide field-of-view scanning antenna for use at millimeter and submillimeter wavelengths, based on the photo-injected Fresnel-zone plate antenna (piFZPA) method. In this paper, we demonstrate the potential of this technology as a viable solution for a range of applications demanding real-time imagery or high flexibility and beam fidelity at these frequencies. We present proof-of-principle experiments at 94 GHz that incorporate a commercial display technology operating at visible wavelengths. The 100-mm-diameter piFZPA achieves 37-dBi directivity, excellent beam symmetry, beam steering in two dimensions over a ±20-deg field of view, and precise beam control and repeatability. Preliminary results of a piFZPA-based, short-range, 94-GHz, three-dimensional imaging radar are also presented.