Design of Practical Matching Networks With Lumped Elements Via Modeling

It is a common practice to utilize commercially available software tools to design matching networks for wireless communication systems. Most of these tools require a properly selected matching network topology with good initial element values. Therefore, in this paper, a practical method is presented to generate matching networks with initial element values. In the implementation process of the proposed method first, the driving point immitance data for the matching network is obtained in a straight forward manner without optimization. Then, it is modeled as a realizable bounded-real input reflection coefficient which in turn yields the desired matching network with reasonable element values. Eventually, the initial design is improved by optimizing the performance of the matched system employing the commercially available computer-aided design (CAD) packages. An example is given to illustrate the utilization of the proposed method. It is shown that new method provides excellent results as a front-end when utilized together with CAD tools.     

Modeling based real frequency technique

Usually commercially available software tools are used, to design matching networks for wireless communication systems. But a properly selected matching network topology with good initial element values must be supplied to these tools. Therefore, in this paper a modeling-based real frequency technique (M-RFT) is presented, to generate matching networks with initial element values. In the proposed method, output impedance data of the matching network are obtained in terms of ABCD-parameters of the load model. Then, they are modeled which in turn yields the desired matching network with initial element values. It is not needed to select a circuit topology for the matching network, which is the natural consequence of the matching processes. Also, there is no need to select the desired transducer power gain level; the proposed technique naturally provides a gain curve fluctuating around a flat level. Eventually, the initial design is improved by optimizing the performance of the matched system employing the commercially available computer aided design (CAD) packages. An algorithm and example are given, to illustrate the utilization of the proposed technique.     

Design of broadband single matching networks

In general commercially available software tools are preferred, to design broadband matching networks for wireless communication systems. But they need a properly selected matching network topology with good initial element values. Therefore, in this paper a new real frequency technique is presented, to generate broadband single matching networks with suitable initial element values. In the proposed method, load impedance is written in terms of ABCD-parameters of the desired matching network and the source resistor. Then, free parameters are optimized which in turn yields the desired matching network with initial element values. It is not needed to select a circuit topology for the matching network, which is the natural consequence of the matching processes. Also, there is no need to select the desired transducer power gain level; the proposed technique naturally provides a gain curve fluctuating around the final available level. Eventually, the initial design is improved by optimizing the performance of the matched system employing the commercially available computer-aided design (CAD) packages. An algorithm and two examples are given, to illustrate the utilization of the proposed technique.     

A Computer-Aided Design Technique for Lossless Matching Networks with Mixed, Lumped and Distributed Elements

A computer-aided method for the design of lossless broadband matching networks with lumped elements and commensurate transmission lines is presented. The method is based on combining the simplifield real frequency technique with the algebraic network decomposition by Fettweis. To show the application of the Computer-Aided Design (CAD) approach, an UHF antenna matching problem is solved.     

基于遗传算法的宽带匹配网络的优化设计

本文采用遗传算法优化设计宽带匹配网络,通过适当的编码可同时对网络的拓扑结构和元件参数进行优化,并给出设计实例,通过与实频法相比较,表明遗传算法设计的匹配网络具有更优的匹配性能,说明遗传算法是一种设计匹配网络的有效方法。     

混合集总—分布参数微波功率分配器的机助设计

在本文中,将微波功率分配器看做用多个两端口网络构成的多端口匹配网络,用集总与分布参数元件混合组成的模块来综合这种网络,从而得到了一种新型的混合集中分布参数微波功率分配器及其机助设计方法。     

低通型阻抗匹配网络的计算机辅助设计

本文在推导阻抗匹配网络输入端反射系数极点解析式和分子多项式的基础上，编写了设计任意偶数阶具有Ｂｕｔｔｅｒｗｏｒｔｈ响应和Ｃｈｅｂｙｓｈｅｖ响应阻抗匹配网络的计算机程序，程序用Ｆｏｒｒａｎ语言编写，当输入匹配网络的阶数ｎ＝２ｍ和阻抗变换比ｒ＝Ｒ２／Ｒ１对Ｃｈｅｂｙｓｈｅｖ响应，通带容许的最大波纹αｄＢ，计算机程序输出匹配带宽和匹配网络归一化元件值。     

An Evolutionary Method for Synthesizing Low-Sensitivity Lossless Matching Networks

Whereas the present practice of designing matching networks for antennas is limited to conventional topologies, requiring a significant amount of domain knowledge, evolutionary algorithms can be used for automatically identifying unconventional designs that are more effective than would otherwise be developed. In this work, an automatic method to design lossless matching networks driven by an evolutionary algorithm (EA) that considers the sensitivities of the network parameters during the synthesis process is presented. To this end, a closed-form expression for the transducer power gain (TPG) sensitivity with respect to the component values is employed in such a way that the effects of the components tolerance on the matching network performance can easily be quantified. A 3D data structure based on the adjacency matrix is conveniently used to represent any type of network topologies. The proposed EA employs a novel set of topology variation operators, tailored for changing the circuit topology, and an association step, with the aim of reducing the number of nodes of the matching circuit. The efficiency of the proposed EA is tested in the synthesis of an impedance matching network for a VHF monopole whip antenna. This study’s results indicate a matching bandwidth improvement, a more uniformly distributed TPG along the operation frequency band and a more stable TPG regarding the components tolerance compared to the results obtained by previous approaches.     

A design method for lumped broadband MMIC matching networks withsemiuniform frequency-dependent losses

A design method for broadband MMIC matching networks which consist of lumped inductors and capacitors is presented. Based on a fictitious transformation between the lossy network and the lossless one, the transducer power gain (TPG) of the lossy network is calculated using impedance matrix and transmission parameter matrix methods. Then, on the basis of the result of TPG optimization, the matching network can be synthesized. Since only the complexity of the matching network needs to be specified, the advantage of the real frequency technique of B.S. Yarman and H.J. Carlin (1982) is retained. In this design procedure the frequency-dependent losses of lumped elements can be considered. Thus the actual gain response tends to coincide with the desired performance more than when the element losses are neglected. An example is given to show the application of the method to broadband GaAs FET amplifier design     

Modeling techniques suitable for CAD-based design of internal matching networks of high-power RF/microwave transistors

A scalable and accurate simulation technique to be used for the computer-aided design (CAD) of matching networks employed within high-power RF transistors is presented. A novel measurement methodology is developed and utilized during the validation of the proposed analysis approach. Appropriate segmentation techniques were developed, which are consistent with the design approach of the high-power transistor, that take into account the overall complexity of the internal match of most modern RF high-power transistors, while preserving important electromagnetic interactions. By being able to properly decouple the linear portion of the overall packaged transistor model, an objective accuracy assessment via the comparison of measured versus simulated results of the internal matching network was accomplished. The level of accuracy obtained provides credence to the idea of a full CAD-driven design process of the internal match of high-power RF transistors.     

基于简化实频方法的宽带天线阻抗匹配网络设计

给出了一种便于工程应用的宽带天线阻抗匹配网络设计方法.在简化实频方法的基础上通过遍历不同网络阶数和零频传输零点阶数下的优化过程,避免了简化实频方法中丢失潜在优良解的问题.设计过程引入对网络的匹配性能和物理实现难易程度的权衡考虑,从所有优化结果中选择最终方案,具有较大的工程实用价值.针对一个实际小型短波宽频带天线的阻抗匹...     

Computer design of linear frequency selective networks

An efficient algorithm is proposed for the computer synthesis of linear networks of arbitrary configuration. Given a circuit approximately realizing a network function T(s), the element values are perturbed until T(s) is precisely realized. In the process, positive elements may be "grown" across nodes as required, or may be forced to desired values. Examples in the areas of passive and active filter design are given, and limitations of the procedure are discussed. Also, the method is shown to be related to the theory of equivalent networks.     

A Simple Method for Millimeter-Wave Finline Balanced Mixer Design Using Three-Dimensional Field Simulation Software

In this paper, a simple method for millimeter-wave finline balanced mixer design using three-dimensional field simulation software has been proposed. The method can be widely used to design the diode-based circuits, especially for the circuit structures with orthogonal field in some specific hybrid integrated circuits which are unavailable to be designed using the circuit simulator. In these circuits, the power directly at diodes is correlated to the input reflection coefficient. The diodes mounted on the finline circuits are defined as impedance boundary in the commercial computer-aided design (CAD) tool High Frequency Structure Simulator (HFSS) model, and hence simulation with the use of HFSS can be implemented to optimize the input matching network of the finline circuits for transferring maximum power to the diodes. Two finline balanced mixers at U-band using commercial GaAs Schottky diodes have been designed and fabricated to validate this method. Matching structures at the radio frequency (RF) port have been employed for a better return loss and a lower conversion loss. Experiment results are presented and show good agreement with simulation data. The proposed method has proven to be useful for the design of millimeter-wave mixers in finline technique.     

An extraction technique for small signal intrinsic parameters of HEMTs based on artificial neural networks

This paper presents a fast and accurate procedure for extraction of small signal intrinsic parameters of AlGaAs/GaAs high electron mobility transistors (HEMTs) using artificial neural network (ANN) techniques. The extraction procedure has been done in a wide range of frequencies and biases at various temperatures. Intrinsic parameters of HEMT are acquired using its values of common-source S-parameters. Two different ANN structures have been constructed in this work to extract the parameters, multi layer perceptron (MLP) and radial basis function (RBF) neural networks. These two kinds of ANNs are compared to each other in terms of accuracy, speed and memory usage. To validate the capability of the proposed method in small signal modeling of GaAs HEMTs, data and modeled values of S-parameters of a 200 μm gate width 0.25 μm GaAs HEMT are compared to each other and very good agreement between them is achieved up to 30 GHz. The effect of bias, temperature and frequency conditions on the extracted parameters of HEMT has been investigated, and the obtained results match the theoretical expectations. The proposed model can be inserted to computer-aided design (CAD) tools in order to have an accurate and fast design, simulation and optimization of microwave circuits including GaAs HEMTs.     

任意横截面形状非均匀介质波导传输特性的分析

用阶梯近似与边缘元和模匹配相结合的方法分析了一大类任意横截面形状非均匀介质波导的传输特性，将非均匀部分用一系列级联的台阶近似，各台阶用微波多模网络等效，用边缘元方法求得各本地波导的本征值问题后，用模匹配法算 出各微波网络的散射参数，最后通过级联的微波网络求得融洽上非均匀结构的传输特性，由于边缘元方法的通用性，此法可对各种不同横截面形状的非均匀介质波导进行分析。     

WDM光传送网计算机辅助设计软件开发

介绍了波分复用（WDM）光传送网计算机辅助设计（CAD）工具。分析了在开发光传送网CAD软件时遇到的关键问题,提出了光传送网CAD软件中网元器件的原子功能模型建模方法。     

Design of RFID tag antennas using an inductively coupled feed

An inductively coupled feed method is explored to design UHF radio frequency identification tag antennas. An analytical model for the proposed feed structure is derived and used to perform simple and wideband impedance match between an antenna and a tag chip without any additional matching networks. The proposed design methodology is verified by comparing the calculations and measurements, which show good agreement.     

CAD technique for designing microwave transistor active filters

A CAD method for designing microwave active filters, based on an extension of the simplified real frequency technique, is presented. This approach is analogous to the design of the matching networks in microwave amplifiers: the filter is developed by cascading active devices with passive two-ports which have a particular form of the transfer function. The potential of the method is illustrated by a computer simulated design of bandpass active filters.<>     

Performance of a meandered line as an electrically smalltransmitting antenna

For antennas to radiate at maximum efficiency, their dimensions must be on the same order as the radiated wavelength. At frequencies below 30 MHz, antennas with efficient radiation are often too large for mobile and portable applications. Smaller antennas can be made to radiate efficiently by use of matching networks. For installation convenience and ease of adjustment, these networks are usually placed between the transmitter and the antenna input; but it has been found that for best radiation efficiency, matching network elements should be placed at points on the antenna structure. Unfortunately, such matching networks must be tuned for each transmitting frequency and, when mounted on the antenna, they cannot easily be tuned. A meander element antenna was found to present some electrical and mechanical properties allowing convenient placement of tuning elements when configured as an electrically small transmitting antenna. Some simplified design guidelines were derived from experimental data     

匹配网络两种设计方法的对比研究

电小天线的阻抗特性非常恶劣,与传输线匹配相当困难,如果是宽带匹配更是难上加难,同时其效率非常低。因此,找到合适的匹配网络的设计方法就很重要了。为了找到较好的设计匹配网络的方法,以某电台的单极子鞭状天线匹配网络的设计为例,通过对匹配网络的两种常见得出方法——理论计算和软件仿真进行了研究,对比分析了误差出现的原因,为匹配网络的研究方法提供了思路。