Fang Dagang

Analysis of open microstrip structures by using diakoptic method of lines combined with periodic boundary conditions

This paper presents the analysis of open microstrip structures by using diakoptic method of lines (ML) combined with periodic boundary conditions (PBC). The parameters of microstrip patch are obtained from patch current excited by plane wave. Impedance matrix elements are computed by using fast Fourier transform(FFT), and reduced equation is solved by using diakoptic technique. Consequently, the computing time is reduced significantly. The convergence property of simulating open structure by using PBC and the comparison of the computer time between using PBC and usual absorbing boundary condition (ABC) show the validity of the method proposed in this paper. Finally, the resonant frequency of a microstrip patch is computed. The numerical results obtained are in good agreement with those published.

Accurate analysis of the coax-to-microstrip transition by using FDTD method

The FDTD method is used to analyze the coax-to-microstrip transition. S/sub 11/ parameters and near-field distributions are discussed when the width of the microstrip is smaller or larger than the diameter of the inner conductor of the coaxial line.

Wavelet algorithm for integral operator equation and its applications to electromagnetic problems

A brief summary of the basic theory of wavelet is proposed. The properties of wavelet function are discussed. The possible applications of wavelet to electromagnetics are given. Examples show that the wavelet method is feasible and effective for solving electromagnetic problems.

Miniaturization of C band LTCC channel receiver front-end SiP module

This paper presents a compact band RF receiver front-end Sip module. The miniaturization is based on the multilayer LTCC subtracts and the use of MMIC and embedded LTCC filters, and the efforts on the electromagnetic compatibility design. In addition, this module accommodates to the planner feeding of local oscillator by using mistrip feed network which is very important in the application of digital beam forming (DBF) system. The designs of low noise amplifier, embedded filters and relative circuits are given. The whole volume of module is 28.0 x 18.0 x 2.15 mm3, which is suitable for designing compact DBF system.

Frequency space-mapped neuromodeling technique exploiting S-B AFS for the design of microwave circuits

In this paper, we present a method of microwave circuits design combining frequency space-mapped neuromodeling (FSMN) approach with S-B adaptive frequency sampling technique. In neuromodeling, frequency space-mapping technique decreases the cost of training, improve generalization and reduce the complexity of NN topology. A Stoer-Bulirsch adaptive frequency sampling (S-B AFS) technique is used to decrease the cost for frequency sweeps in sampling. We use S-B AFS technique for FSMN implementation. The example of designing a microstrip parallel-coupled bandpass filter by means of electromagnetic bandgap (EBG) structure confirms the validity of this approach in both reducing the sampling time and increasing the accuracy of the neuromodeling.

Implementation of anisotropic PML for frequency domain FEM solution of discontinuity in dielectric waveguide

The anisotropic Perfectly Matched Layer(PML) absorbing boundary condition is implemented in a 2-D finite element formulation to solve dielectric waveguide discontinuity problems. The choice of parameters of anisotropic PML has been investigated. Using the boundary truncating technique, the solution process of Finite-Element Method (FEM) has been greatly simplified compared with other hybrid methods. The required computational resources have also significantly declined since the anisotropic PML interface can be placed much closer to the scatterer compared to other well known artificial boundary.

Algebraic multi-grid method in two-dimension electrically large problems

In this paper the algebraic multi-grid principle is applied to the multilevel moment method, which makes the new multilevel method easier to implement and more adaptive to structure. Moreover, the error spectrum is analyzed, and the reason why conjugate gradient iteration is not a good relaxation scheme for multi-grid algorithm is explored. The numerical results show that our algebraic block Gauss Seidel multi-grid algorithm is very effective.

The multi-grid block Gauss Seidel fast multipole method in electrically large problem

In this paper we applied fast multipole method (FMM) to Block Gauss iteration and used this new iteration algorithm as the relaxation scheme in the multi-grid scheme, which is termed as multi-grid block Gauss Seidel fast multipole method (MGBGSFMM). Numerical results show that this method is very effective.

Optimal approximation algorithm of feature coefficients and identification of target

On the basis of target transfer function with the early time and late time response together, a method for solving the feature coefficients of target is investigated by utilizing approximation theory and method. Then, the feature coefficients are classifled by the minimum distance criterion to identify targets automatically.