A millimeter wave beam shaping phased antenna array proposed for imaging reflectometry

Summary form only given, as follows. A millimeter wave phased antenna array has been proposed for use in plasma imaging reflectometric diagnostics and is currently under design and fabrication. To account for the rapid changes of the cutoff layer with plasma density variation, a true time delay controlled phased antenna array (PAA) is being developed as an artificial lens with controllable, focal length,for launching the illumination beam of the microwave imaging reflectometry (MIR) system. The beam shaping concept illustrates that programming the PAA generates concave (focusing/beam narrow) or convex (defocusing/beam broaden) wavefronts by properly arranging the time delay (or phase shift), therefore, the PAA functions like a real optical lens. The focal properties can be easily changed by different time delay arrangement at high speed so that real time control is possible on time scales significantly faster than plasma changes.