Application of local plane wave decomposition for determination of radiation field of secondary aperture

Localization of plane wave expansion using the method of quasisolution searching

“…where w is the width of the window. The system of non-intersecting rectangular windows with centers on the grid xi = iw, i ∊ (-∞,∞) is orthogonal, the window is specified on the finite support and the transition from local to global representation is implemented as simply as possible by summation [5]. In this case, the formed system of local spectra of plane waves     , i i U    determines the initial global spectrum of plane waves U(κ) by its sum…”

“…However, for some problems the disadvantage of the plane wave expansion is its globality, since it is determined by the field spatial distribution along the full real axis [3,4]. On the other hand, the efficiency of this approach can be increased by going over to obtaining a spectral representation of the radiation field for a limited fragment of the aperture [5]. The localization of the expansion should allow extracting a set of dominant directions of wave propagation for each specific limited fragment of the field distribution under consideration.…”

“…The problem of globality manifests itself especially clearly in the numerical implementation of the plane wave expansion for processing experimental data [4]. In this case, the plane wave spectrum (PWS) can be numerically obtained using a discrete Fourier transform (DFT), which involves the use of discrete samples of the field distribution, specified on a finite support [5]. The size of the used interval is determined by the degree of divergence of the wave beam under consideration and the distance to the plane in which the transverse distribution of the field is supposed to be restored [4].…”