Computationally effective wideband combined worst-case model of monopole antenna coupling

A computationally effective wideband worst-case model of spurious coupling between monopoles placed at line of sight of each other is proposed. The model is constructed by combining analytic solutions of the problem for low-frequency and high-frequency bands by means of weight function determined empirically. The low-frequency solution is used at frequencies below the main resonance frequency of the longer monopole, and it is based on induced emf method. This solution takes into account the mismatch of antennas with a source and a load, and it is validated in three-decade frequency range. The high-frequency solution is based on the equation for free-space transmission of radio waves. The model can be used in the framework of express analysis of EMC to calculate mutual influence of monopoles installed on the fuselage of an aircraft. Validation of the proposed model and determination of its applicability region are performed by comparing results computed by the model with results of numerical modeling by the method of moments (MoM) for the following values of parameters: ratio of the fuselage diameter to the antenna length is varied from 1.75 to 12.5, ratio of a distance between the antennas to the antenna length is varied from 1.00 to 12.5. For additional validation, the comparison of results computed by the proposed model with results of numerical modeling by the finite element method (FEM) for two blade antennas AT-1076 installed at KC-135B airplane is performed.