A closed-form low-frequency statistical model for field-to-wire coupling in twisted-wire pairs with non-ideal twisting

A statistical model is developed to predict the noise induced in the terminal loads of a TWP running above ground and illuminated by a plane-wave electromagnetic field. The model accounts for random variations of the pitch of the bifilar helix formed by wires, and is derived under the assumption that the TWP is electrically-short at the frequency of interest. The obtained closed-form formulation makes the proposed model computationally efficient and suitable to perform extensive parametric simulations, aimed at unveiling the impact played by the geometrical features of non-uniform twisting on the statistical estimates of the induced noise.