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This paper numerically investigates the radio wave scattering by the artificial acoustic disturbance in the atmospheric boundary layer. The numerical model is based on the finite-difference time-domain (FDTD) method for radio wave propagation and fluid simulation for atmospheric disturbance by acoustics waves. The characteristics of radio wave scattering propagation in the artificial acoustic perturbations are investigated by this numerical model. The numerical simulation results demonstrate that the radio wave propagation scattered by acoustic scatterer has the characteristic of forward tropospheric scatter. When the radio waves are scattered, they distribute in all directions; a majority of radio waves continues to propagate along the original direction, and only a small part of the energy is scattered. For the same acoustic scatterer, if we merely change the radio wave emission elevation, the horizontal spans of forward scattering radio wave packets centers gradually decrease with the increasing of emission elevations; and the energy of wave packets increases firstly and then decreases with launching elevation, reaching the maximum at a certain angle. If we merely change the wave emitting position, the horizontal spans decrease with the increasing of emission positions, and the energy of wave packets also increases firstly and then decreases with launch position, reaching the maximum at a certain position. This approach can be very promising for atmospheric scatter communications. [ABSTRACT FROM AUTHOR]

The temperature-drift effect of microstrip filters is analyzed by the proposed electromagnetic-thermal co-simulation method based on parallel high-order discontinuous Galerkin time domain (DGTD) and finite-element time-domain (FETD) algorithms with a memory reduction technique. The element matrices of DGTD method are factorized into the product of coefficient matrices and universal matrices. The coefficient matrices are different for each tetrahedral element and need to be stored for all the elements. While the universal matrices are the same for all the tetrahedral elements and only need to be stored for one element. Since the sizes of the coefficient matrices are much smaller than the element matrices of DGTD method, the proposed method avoids storing the large element matrices and greatly reduce the memory requirement of the DGTD method. Thus it reduces the memory requirement of the whole electromagnetic-thermal co-simulation which is dominated by the memory consumption of the DGTD method. Large-scale parallel technique is adopted to accelerate the process of electromagnetic-thermal co-simulation. The proposed method provides a very powerful tool for temperature-drift effect analysis of microstrip filters. [ABSTRACT FROM AUTHOR]

In this paper, we mainly investigate a (2+1)-dimensional coupled nonlinear partial differential equation with variable coefficients in an inhomogeneous medium. Based on the Hirota bilinear form and symbolic computation, the breather wave solutions and lump solutions are constructed by using the extended homoclinic breather technique and the generalized positive quadratic function method. Also, Hirota bilinear method is applied to considered equation for finding N-soliton wave solutions. When the coefficients of the equation are different, the corresponding improved results are obtained for some special equations. Furthermore, by plotting the images of different types of solutions, their dynamic behaviors are analyzed. • In this paper, we mainly investigate a (2+1)-dimensional coupled nonlinear partial differential equation with variable coefficients in an inhomogeneous medium. • Based on the Hirota bilinear form and symbolic computation, the breather wave solutions and lump solutions are constructed by using the extended homoclinic breather technique and the generalized positive quadratic function method. • In Section 5, we add the N-soliton solution of the studied equation, and analyze the dynamic propagation behavior of one-soliton solution and two-soliton solution of the equation. • When the coefficients of the equation are different, the corresponding improved results are obtained for some special equations. [ABSTRACT FROM AUTHOR]