Some new methods of analysis and synthesis of near-zone fields

In this paper, the following new methods of analysis and synthesis of near-zone, including Fresnel-region, fields will be presented: 1) A principle of subdivision and methods of near-zone field analysis. This principle makes possible the use of far-field techniques in near-zone field analyses. 2) A near-zone field synthesis method based upon the principle of subdivision. This method bears a close resemblance to the Woodward method of far-field synthesis. 3) A focusing theorem and a second near-zone field synthesis method. This method transforms a near-zone synthesis problem into a far-field problem, therefore any synthesis method applicable in the far-field can also be applied here. 4) Fresnel-region field analysis of a circular aperture. The results are expressed in terms of a class of new functions which are closely related to the Lommel's functions of two variables. Simple method of evaluating such functions will also be given. 5) A second focusing theorem and Fresnel-region field synthesis. The synthesis is also based upon far-field methods. Examples of both near-zone synthesis methods are included. Merits of each method are also discussed.