Polynomial attenuation window function for microwave propagation in evaporation ducts using the parabolic equation method

This paper employs the parabolic equation method to investigate the influence of upper boundary conditions on microwave propagation in evaporation ducts, with the aim of improving simulation accuracy for long-distance wireless power transfer. A novel window function termed Polynomial Attenuation (PA) is proposed, exhibiting an attenuation behavior distinct from that of conventional window functions. Unlike traditional approaches that require the window function to decay to nearly zero at the truncation boundary, the proposed function is shown to effectively suppress boundary reflections even when its value remains at ∼0.8. Numerical results demonstrate that under various simulation conditions, the PA window reduces the maximum relative error by at least 10 dB compared with conventional window functions, thereby improving simulation accuracy and indicating its applicability to a range of complex propagation scenarios.