Computationally-effective ultra-wideband worst-case model of electromagnetic wave diffraction by aperture in conducting screen

A worst-case model of the plane wave diffraction by the rectangular or circular aperture is proposed. The model is intended for EMC analysis in a frequency range from 1 Hz to 40 GHz, and it is based on combining the analytic solutions of the diffraction problem for low-frequency, resonance, and high-frequency ranges. The combining is carried out by the use of matching functions which define a contribution of each analytic solution. The correctness of the proposed model was checked by comparison with numerical solutions of the diffraction problem in a wide range of the parameters' values: ratio of the wavelength to the maximal dimension (diagonal or diameter) of the aperture is from 0.05 to 300; ratio of rectangular aperture sides is from 1 to 100; ratio of the distance (from the aperture center to the observation point located behind the screen at arbitrary position) to the maximal dimension of the aperture is from 0 to 1000.