射频阻抗测量夹具建模技术的研究及应用

分析了阻抗测量夹具中由于阻抗不连续以及信号传输结构变换引起信号的反射,建立PCB板微带传输线、同轴传输线至微带线的转接的模型,最后介绍从测量结果中消除夹具影响的方法.使用自制夹具测量0603封装的贴片器件, 并利用文中介绍的方法进行建模和去嵌入处理,最终获得贴片器件的射频特性;同时可以得到微带线的特性,实际验证了该方法的正确性.     

A planar-lumped model for coupled microstrip lines anddiscontinuities

A convenient model for analyzing coupled microstrip line discontinuities is presented. A planar-lumped model similar to the planar waveguide model for single microstrip lines is developed for coupled microstrip lines. Fields underneath the two strips and those fringing at the outer edge are modeled by two equivalent planar waveguides. Electric and magnetic field coupling in the gap region is modeled by a lumped network. The lumped network parameters are evaluated such that [C] and [L] matrices for the model are identical with those for coupled lines. The model is verified by comparing coupler characteristics with those obtained by the conventional coupled line analysis. Just as the planar model of a single microstrip has been used for characterizing microstrip discontinuities, the planar-lumped model developed is used for coupled line discontinuities. Examples given include coupled microstrip sections with chamfered bends located at right angles to single microstrip lines, for which the results are in good agreement with experimental values     

A generalized method for distinguishing between radiation andsurface-wave losses in microstrip discontinuities

A generalized method for calculating both radiation and surface-wave losses is developed for microstrip discontinuities. The losses are determined by a rigorous Poynting vector analysis where the current distribution over the microstrip discontinuities is a result of a full-wave moment method solution. The power loss mechanism of such microstrip discontinuities as open-end, right-angle-bend, gap and stub lines, EMC lines, and rectangular patches are investigated. A self-consistency check of the result based on power conservation is performed to confirm the numerical results. It is found that, above a certain frequency, the surface-wave loss becomes more important than the radiation loss     

时域有限差分法分析微带不连续性

本文采用时域有限差分（TD－FD）法分析微带不连续性问题，在研究分析方法的同时，着重分析了微带双分路线，同时还对微带阶梯，微带间隙和微带终端开路进行了分析，准确地求出了它们的散射参数，显示了TD－FD方法在解决微波电路问题上具有广泛的应用前景。     

Computer-Aided Design of Microstrip Filters Considering Dispersion, Loss, and Discontinuity Effects

A computer-aided design procedure of microstrip filters involving junctions and discontinuities is investigated. The analysis of microstrip filters is described in detail considering disperion, loss, and the frequency dependent properties of the microstrip discontinuities. It is found that the described analysis procedure leads to an accurate fast numerical computation of the microstrip filter properties. The theoretical results for some filter structures are compared with measurements, and theory and experiment are found to correspond closely.     

Transient analysis of dielectric step discontinuity of microstrip lines containing a nonlinear layer

Tansient signal propagation characteristics through step discontinuities on microstrip lines with nonlinear substrate are presented. In the proposed model structure, the transient electromagnetic wave propagates from microstrip line with linear substrate to one with nonlinear substrate or vice versa, where two structures are connected to create abrupt discontinuities. The distortions of transient signal through this two abrupt discontinuity structures are numerically simulated by three dimensional FD-TD method. Results show that the distortions of transient signal are evidently influenced by the density of electric field propagating along the microstrip line with nonlinear substrate.     

Calculation method for microstrip discontinuities and T junctions

A method for calculating microstrip discontinuities and T junctions is described, and a waveguide model for the microstrip line is defined. With the help of this model and the use of an orthogonal series expansion, a solution of the above problems is found. Numerical results for the scattering matrices of both the discontinuities and the junctions are given.     

Surface wave excitation from open microstrip discontinuities

Radiation properties of open microstrip discontinuities are investigated using a full-wave integral equation technique. Formulas are presented to characterize power loss from open microstrip discontinuities. The technique utilizes microstrip current distributions obtained with the method of moments. The formulas allow the separation of total loss into the individual contributions of space wave and surface wave radiation and indicate the direction in which surface wave power is propagating within the substrate. Patterns depicting the power propagating in the substrate have been computed and verified experimentally     

Fast location of high-order modes for boxed microstrip with finite strip thickness

Many analyses of boxed microstrip discontinuities require the location of large numbers of high-order modes. Using Sturm-Liouville theory, this letter derives a relationship between microstrip modes and slab-loaded guide modes, leading to an efficient mode location algorithm for microstrip, including microstrip with finite strip thickness.<>     

Comparison between theoretical and measured microstrip gapparameters involving anisotropic substrates

In this paper, experimental results are presented for microstrip symmetrical-gap discontinuities. The experimental technique is based on the measurement of the resonant frequencies of several gap-coupled rectangular microstrip resonators. In particular, gap discontinuities on anisotropic dielectric and two-layer composite substrates have been investigated. Reasonably good agreement has been found in most cases between theoretical data [obtained by means of the excess charge technique in the spectral domain (EC-SDA)] and experimental data, even though the theoretical results have been obtained by using a quasi-static approach     

应用史密斯圆图提取慢波微带线特征阻抗方法

慢波微带线的多种不连续性和相邻慢波单元的耦合影响了特征阻抗的准确计算,因此在慢波微带线的设计阶段需要一种手段来提取其特征阻抗。提出一种利用史密斯圆图提取慢波微带线特征阻抗的方法,该方法通过观察慢波微带线的反射系数在史密斯圆图中的图像估计其特征阻抗的大小,并通过反射系数极值计算特征阻抗。以梳状慢波微带线为例检验该方法,特征阻抗的提取结果与利用S参数提取的结果十分接近,从而证明该方法是一种可行的慢波微带线特征阻抗提取方法。     

Effect of substrate dielectric anisotropy on the frequency behaviorof microstrip circuits

In this paper, we carry out a full-wave analysis of shielded two-port microstrip circuits, in which the metallizations are embedded in a multilayered substrate that may contain isotropic dielectrics and/or anisotropic dielectrics. The Galerkin's method in the spectral domain is applied for determining the current density on the metallizations of the circuits when their feeding lines are excited by means of delta-gap generators, and the matrix pencil technique is subsequently used for deembedding the scattering parameters from the computed current densities. Results are presented for the scattering parameters of some microstrip discontinuities and filters printed on both isotropic dielectric substrates and anisotropic dielectric substrates. These results show that when substrate dielectric anisotropy is ignored, errors arise when computing the scattering parameters of microstrip discontinuities and when predicting the operating frequency band of microstrip filters     

A Resonance Method for the Broad-Band Characterization of General Two-Port Microstrip Discontinuities

The paper describes an experimental procedure suitable for broad-band characterization of two-port microstrip discontinuities of any topology. The resonance frequencies of a transmission-type cavity embedding the discontinuity under test and of a set of reference fines are measured and computer processed to obtain the scattering parameters the discontinuity itself. This method features extreme ease of application thanks to the limited number and simple topology of the required microstrip samples, as well as highly accurate and repeatable results. Furthermore, the scattering matrices obtained from the measurement are automatically normalized with respect to the wave impedances of the qnasi-TEM modes in the outgoing microstrips. This makes possible an analysis and design approach not requiring the knowledge or calculation of microstrip characteristic impedances.     

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     

Characterization of radiation loss from microstrip discontinuitiesusing a multiport network modeling approach

A convenient method for evaluating radiation loss from microstrip discontinuities is presented. A planar multiport network model of the discontinuity configuration and the segmentation method are used to evaluate the voltage distribution around the edges of the discontinuity. This voltage distribution is expressed as an equivalent magnetic current line source distribution which is used to calculate the far-zone field (for radiation loss). As an example, the results show that for a 90° bend in a 50-Ω line on a 10-mil-thick substrate with ϵ_r =2.2, the radiation loss is 0.1 dB at 30 GHz. Typical power levels radiated by several other discontinuities are reported. The analysis model was verified experimentally by fabricating microstrip resonators with discontinuities incorporated therein and measuring the Q factors of these resonators     

A new CAD model for the full-wave characterization of microstrip line and its discontinuities

This work presents a new mathematical model for characterization of the microstrip and its discontinuities by the dynamic approach based on the exact Green's function for a grounded dielectric slab and the ameliorated Galerkin method. Some improvements are brought to the theoretical model of Jackson and Pozar (1985, IEEE Trans. Microwave Theory & Techniques, 33, 1036–42), which is our starting point. The present model has given very good results for the characterization of the microstrip line and its discontinuities of open end and gap, compared with previous theoretical and experimental results.     

Time-Domain Measurement of Loss and Dispersion (Short Papers)

Time-domain metrology (TDM) techniques are applied to determine loss and dispersion in microstrip and coaxial cable for possible future use in interconnections in the frequency range of 0.4-10 GHz. After a brief presentation of the method, results are given for microstrip, RG/U 58, and RG/U 188A coaxial cable. Good agreement is obtained between measured, computed, and published values. Major advantages of the technique are that unwanted multiple reflections can be excluded from the measurement time window, and errors from interface discontinuities can be evaluated and removed from the final result.     

A rigorous dispersive characterization of microstrip cross and Tjunctions

A full-wave spectral-domain analysis is applied to the characterization of multiport microstrip discontinuities. This method uses the moment method to find the currents in the microstrip circuits and subsequently the scattering parameters of the junctions. In this approach, all the physical effects are considered, including radiation and surface waves. The numerical results for a T- and a cross-junction are presented and agree well with the quasi-static values at low frequencies. The S-parameters of a T-junction are further compared with the measured results, with excellent agreement. The utilization of a shaped T-junction as a broadband equal-power divider is also discussed