ERROR ANALYSIS OF FRESNEL-RING FOCUSING.

A general end-fire array design technique called Fresnel-ring focusing for direct extrapolation of far-field data from near-field data has been analyzed with regard to systematic and random errors. Criteria are developed for sufficiency of the Fresnel approximation with arbitrary array design, array element gain, and the restrictions of mutual coupling that demonstrate feasibility of the technique for a practical problem. Consideration is given to focusing processes and types of optimization synthesis. Array optimization is achieved by design variation to minimize random errors. The end-fire array designs attained have super-gain properties that make the technique impractical. Author