Application of the three-dimensional finite-difference time-domainmethod to the analysis of planar microstrip circuits

A direct three-dimensional finite-difference time-domain (FDTD) method is applied to the full-wave analysis of various microstrip structures. The method is shown to be an efficient tool for modeling complicated microstrip circuit components and microstrip antennas. From the time-domain results the input impedance of a line-fed rectangular patch antenna and the frequency-dependent scattering parameters of a low-pass filter and a branch-line coupler are calculated. These circuits were fabricated and the measurements made on them are compared with the FDTD results and shown to be in good agreement     

Harmonical characterization of a microstrip bend via the finitedifference time domain method

A 90° microstrip bend is characterized using a time-frequency method based on the finite-difference-time-domain (FDTD) method. Time evolution of the currents generated by FDTD are Fourier transformed to lead to S-parameters and the radiated powers characteristic of the microstrip bend. The method for calculating both radiation and surface wave losses is developed for microstrip structures. The results of the 90° microstrip bend are compared with the results of the mitered microstrip bend     

Accurate analysis of H-shaped antenna coupled to microstripfeed-line

An accurate investigation of a microstrip H-shaped antenna is presented, coupled by means of an aperture or via-hole to a microstrip feed-line. The EM analysis is performed by means of the hybrid transmission line matrix-integral equation method. The calculated S-parameters are compared to measured results and to those obtained by the generalised transverse resonance-diffraction method     

Corner Function Analysis of Microstrip Transmission Lines

A new method of analysis of microstrip transmission lines using corner functions (eigenfunctions) is presented. Assuming the TEM mode propagation for the shielded microstrip line structure, solutions are set up in a series of corner functions, which isolates the singularity at the edge of the strip. The boundary conditions are satisfied by using a method of successive integration of boundary errors. Numerical results are obtained for the charge distribution from which the microstrip line characteristic impedance is determined. Excellent agreement with published theoretical results and experimental data is obtained. The numerical results clearly bring out the power of the method.     

Full-wave analysis of the annular-ring loaded spherical-circularmicrostrip antenna

In this paper, an annular-ring loaded (ARL) spherical-circular microstrip antenna is studied theoretically. The antenna is excited by a coaxial probe. The theoretical formulation is based on full-wave analysis in the spectral domain by using the vector Legendre transform and Galerkin's moment method is used for numerical calculation. Numerical results of the resonance frequencies, input impedance, voltage standing wave ratio (VSWR), and radiation characteristics are presented. It is shown that the impedance bandwidth of the spherical-circular microstrip antenna can be broadened by adding an annular-ring parasitic patch. By comparing to the single circular-patch case the spherical-circular microstrip antenna with an annular-ring parasitic patch has larger minor lobes and larger cross-polarization radiation     

Investigation of the dispersion characteristics of strip lines in centimeter and millimeter wave bands

The dispersion characteristics of delay and losses in microstrip, suspended microstrip, and singlestrip lines are analyzed numerically in a wide frequency band for different parameter combinations. The analysis is based on the finite-element method. The results of electrodynamic simulation and physical experiment are compared.     

基于FFT-BCG的微带天线研究

将全波分析与快速傅里叶变换及双共轭梯度相结合,对微带天线进行分析计算,结果表明,计算结果同实测结果吻合较好,说明了该分析方法的正确性和有效性.同时,该方法提高了计算速度,为微带天线的快速分析和计算提供了良好的借鉴.     

Analysis of Microstrip Resonators

An accurate and efficient method was developed for computing the resonant frequencies of microstrip resonators. The formulation of the problem was carried out rigorously using the full-wave analysis rather than the quasi-static approximation. The characteristic equation was derived using Galerkin's method applied in the Fourier transform domain. The accuracy of the method has been proven by comparing the numerical results with the experimental data. Numerical data have been provided for the microstrip resonators with different structural parameters. Finally, the results for microstrip resonators have been used for predicting the end effect at the open end of microstrip structures.     

Analysis of aperture-coupled microstrip-Antenna and circuitstructures using the transmission-line-matrix method

The transmission-line-matrix method is a numerical technique for solving Maxwell's equations in the presence of complex environments. A general-purpose simulation program, based on the three-dimensional symmetrical-condensed TLM model, is presented. Previous applications of the simulation program include the analysis of half-space and remote-sensing problems, and calculation of the radar cross section of finite-sized conducting materials and objects. The simulation program is applied to the characterization of aperture-coupled microstrip structures. Numerical results, pertaining to the analysis of aperture-coupled microstrip lines, offset-aperture-coupled microstrip lines, and aperture-coupled microstrip-patch antennas, indicate the accuracy and utility of the program for analyzing aperture-coupled microstrip configurations. A discussion of the accuracy and efficiency of the approach is included, with limitations and possible improvements     

任意形状单元有限微带阵列的电磁散射分析

提出一种有限微带阵列电磁散射特性分析的有效方法。该法采用有限阵格林函数与矩量法相结合的方法，有效地解决了矩量法在大型阵列电磁特性分析中的计算效率问题；通过选取RWG基函数，使该法适用于任何单元形状的微带阵列。文中计算了矩形、十字形及圆形单元微带阵列的雷达截面，并与常规矩量法和参考文献的计算结果进行了比对，验证了该方法的有效性。     

Analysis of the annular-ring-loaded circular-disk microstripantenna

A rigorous analysis of the natural resonance frequencies and input impedance characteristics of an annular-ring-loaded (ARL) circular-disk microstrip antenna is presented. Using vector Hankel transforms, the problem is formulated in terms of vector dual-integral equations. Galerkin's method is then used to solve the equations to obtain the resonance frequencies and the current distribution on the conductive patches arising from a probe excitation. Due to the singular nature of the current distribution, the singularity subtraction method has been used to accelerate the convergence of basis function expansions. Experiments for determining resonance frequencies and input impedance characteristics of an ARL circular-disk microstrip antenna with various substrate thicknesses have been made. The theoretical results are in good agreement with the experimental data even when the thickness of the substrate is 0.1 substrate wavelength. It is shown that this theory can be used to analyze some microstrip antennas with an electrically thick substrate, including the analysis of mutual coupling between conductive patches or between the path and the feed of a microstrip antenna     

基于FDTD的相控微带天线阵设计与分析

针对相控微带天线阵设计、分析过程的复杂性,提出了用时域有限差分法(FDTD)对微带天线阵进行建模,用仿真软件Emp ire获取数据,结合直线阵理论和传输线理论导出相应的公式,用M atlab进行数据处理的设计、分析方法。用该方法设计了一个七单元相控微带天线直线阵。优化设计后,分析了动态反射系数、方向图等。通过实例将该方法分析结果与仿真曲线进行了对比,其吻合程度验证了该方法的准确性。研究表明,这种方法有利于相控微带天线阵的快速设计。     

Computer analysis method for arbitrarily shaped microstrip antenna with multiterminals

An analysis method is presented for an arbitrarily shaped microstrip antenna with multiterminals. The method is based on the variational method and the modal-expansion technique. Eigenvalues and eigenfunctions are determined using the Rayleigh-Ritz method. Input impedance and other antenna parameters are derived at nonresonance. Furthermore, the network model, useful for the network analysis of a microstrip antenna with multiterminals, is presented by introducing an ideal transformer. Finally, numerical examples are compared with experimental results. The agreement is quite good, and the validity of the present method is confirmed.     

Analysis of a wide radiating slot in the ground plane of amicrostrip line

An analysis of a wide rectangular radiating slot excited by a microstrip line is described. Coupled integral equations are formulated to find the electric current distribution on the feed line and the electric field in the aperture. The solution is based on the method of moments and using the space domain Sommerfeld-type Green's function. The information about the input impedance or reflection coefficient is extracted from the electric current distribution on the microstrip line utilizing the matrix pencil technique. The theoretical analysis is described and data are presented and compared with other theoretical and experimental results     

Computation of microstrip S-parameters using a CG-FFT scheme

Several open microstrip structures have been analyzed by using the conjugate gradient fast Fourier transform (CGFFT) method to solve the electric field integral equation (EFIE). The analysis of the microstrip structure provides equivalent electric currents on the conducting patches. Extensive computation is performed in the spectral domain. Windowing techniques are used to improve the accuracy of the method. New models for the microstrip feed and load have been developed in combination with the CGFFT method. Results for the S-parameters are compared with the results of other methods and with measurements. The method appears to be accurate and computationally efficient     

Broad-band cavity-backed and capacitively probe-fed microstrippatch arrays

A hybrid full wave method for the analysis of probe-fed infinite phased arrays of single and stacked microstrip patches, backed by metallic cavities, is applied to investigate the combined utilization of the capacitive probe-feeding technique and the cavity enclosure of microstrip patches. The goal is to obtain broad-band microstrip antennas on thick substrates without the limitations due to the generation of surface waves of the conventional microstrip antennas on infinite substrates. A design procedure for the capacitive coupling is investigated and theoretical results for the active input impedance and radiation characteristics of different wide-band antenna designs are presented     

基于复合基底微机械微带特性研究

研究了一种复合基底微机械微带,通过理论推导得出微机械微带的特性计算表达式。首先用计算机模拟该微机械微带的性能,再用表面微细加工工艺加工了该微机械微带模型,最后用安捷伦矢量网络分析仪器测试模型,得出该微带在100GHz内无色散,最大损耗小于2dB。该微机械微带利于集成、尺度微小,可应用在微波、毫米波通信系统(器件)中,克服了常规微带在高频工作时色散严重、损耗大等缺点。     

Full-wave space-domain analysis of open microstrip discontinuitiesincluding the singular current-edge behavior

A full-wave space-domain analysis is presented for the high-frequency characterization of microstrip discontinuities. This approach solves the electric field integral equation (EFIE) for the surface current density on the microstrip using the method of moments. The current expansion functions incorporate the singular edge behavior of the surface current, yielding a very accurate current modeling. Special attention is devoted to the analytical treatment of the singular terms in the electric field Green's dyadic. The numerical results focus on the S-parameters of some simple microstrip discontinuities and the comparison with results obtained with other techniques and from measurements     

Analysis and synthesis of tapered microstrip transmission lines

The input voltage reflection coefficient on a tapered microstrip transmission line is analyzed and a new Fourier transform pair is derived which introduces echo time and frequency as variables. Calculations of the input reflection coefficient take into account the frequency dispersion-characteristics of the effective permittivity. An efficient method is proposed for analysis and synthesis of microstrip tapers and numerical results are presented for microstrip exponential tapers and microstrip Chebyshev tapers     

采用PML吸收边界条件的FDTD法在分析平面微带结构中的应用

本文将理想匹配层(PML)吸收边界条件用于平面微带结构的时域有限差分法(FDTD)分析中,给出平面微带结构的PML吸收边界条件,并编制程序,进行数值计算。结果表明,与传统的Mur吸收边界条件相比,采用PML吸收边界条件只需采用最简单的馈源模型就可明显地减小计算网格空间和加快收敛速度,并且可用于分析任意复杂结构的微带电路。本文方法对微带电路及微带天线的CAD设计将具有实际意义。