Study on calculation and verification of radiowave propagation using parabolic equation for the antenna near the ground

In this paper, with planar layered media as physical model, wire antennas installed near the ground are strictly analyzed using discrete complex image method (DCIM) firstly. Then a new method that uses antenna current to set initial field of parabolic equation methods are proposed, which solved the problem that the aperture cannot support the initial field in low mounted height of antenna conditions through traditional methods. A direct connection is built between initial field and antenna current distribution. Using the new method, propagation factors of two pairs of LPDA under different conditions are calculated, and the results show the new method's feasibility and effectiveness, which is superior to image method and reflection coefficient methods. With the benefit of the new initial field setting method we can unify the initial radiation sources of the ray model, UTD model and PE model, which provides premise to use UTD and ray model to test the accuracy of PE method. Firstly the staircase terrain and piecewise linear terrain model of PE method for electromagnetic wave propagation via troposphere over irregular terrains are addressed. Then the loss factors of electromagnetic wave propagation over a knife-edge and a wedge terrain are calculated using the UTD, Ray and PE algorithms. Comparing the results, PE method has well consistent with UTD, which shows the accuracy of PE for radiowave propagation analysis. The comparison also shows the accuracy of piecewise linear terrain model is better than the staircase terrain model.