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.     

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.     

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.     

一种宽带全向圆极化天线简

 基于环天线-偶极子模型,本文提出一种宽带全向圆极化天线.天线包含四对围绕圆柱放置的倾斜振子和一个宽带馈电网络.每对振子包含一个主辐射振子和一个用以增加带宽的寄生振子.馈电网络包括四个宽带巴伦和一个阻抗匹配电路.实验结果表明,该天线15-dB回波损耗带宽和3-dB轴比带宽分别为31%（1.68-2.31GHz）和30%（1.7-2.3GHz）,水平面不圆度小于1dB.     

一种新型双频宽负载整流电路

提出一种新型双频宽负载整流电路,它能有效回收环境中的微波电磁能量.该整流电路主要由阻抗压缩匹配网络、肖特基二极管和低通滤波器构成.其中,阻抗压缩匹配网络由一个L型阻抗调节器和一个Ⅱ型阻抗匹配器组成,该网络能够在200 ～ 4000Ω的负载区间内减小输入阻抗的变化范围,从而提高整流电路的匹配性能.ADS 2017软件仿真...     

Broadband impedance matching via lossless unsymmetrical lattice networks

In this paper, a broadband impedance matching network (equalizer) design algorithm has been proposed. In the equalizer, a lossless unsymmetrical lattice network has been utilized. The branch impedances of the lattice network are considered as singly terminated lossless LC networks, since it is not desired to dissipate power in the equalizer. After giving the algorithm, its usage has been illustrated via an example.     

Non-Foster Impedance Matching of Electrically-Small Antennas

Electrically-small antennas present high-Q impedances characterized by large reactances and small radiation resistances. For such antennas, the effectiveness of passive matching is severely limited by gain-bandwidth theory, which predicts narrow bandwidths and/or poor gain. With receivers, the inability to resolve this impedance mismatch results in poor signal-to-noise (S/N) ratio, as compared to using a full-size antenna. With transmitters, the consequence is poor power efficiency. However, in many applications full-size antennas are impractical, and a means is required to effectively match their electrically-small counterparts. This paper presents the technique of non-Foster impedance matching, which employs active networks of negative inductors and capacitors to bypass the restrictions of gain-bandwidth theory. We first review the origins and development of non-Foster impedance matching, and then present experimental results for the non-Foster impedance matching of electrically-small dipoles and monopoles. For receivers, our best measurements on the antenna range demonstrate up to 20 dB improvement in S/N over 20–120 MHz; for transmitters, we show a power efficiency improvement which exceeds a factor of two over an 5% bandwidth about 20 MHz with an average signal power of 1 W to the radiation resistance.      

一种双波段可重构功率放大器仿真设计

可重构输入匹配采用一种基于L型的电路结构,通过一个单刀单掷开关电路使该结构接入一段微带线,实现不同工作频率下输入阻抗的自动补偿。输出匹配实现并发双频段工作,在早期三段式微带线的基础上重新进行公式推导,提出了更易实现的四段微带线串联结构。该功率放大器采用了可重构结构与并发双波段匹配网络结合的方式,因此只采用了一个开关。电路结构简单,且开关切换时对电路性能影响较小。仿真结果表明,该功率放大器的匹配状态和性能良好,为现有的可重构功率放大器设计提供了一种思路。     

使用无线局域网(ZigBee)的测量参数传输方法

针对外场设备测试环境的特殊性和实时性要求,对设备间的信号采集与传输,提出了一种结合无线传输技术和机敏传感网络技术的高精度多参数测量方法.重点阐述了无线传感嚣网络(ZigBee)拓扑结构协议设计思想,利用边界节点作为路由器起到簇与簇间的中继作用,实现簇间通信;以温度测量为例,给出了传感节点的设计方案,利用巴伦电路实现传感...     

Gain-Bandwidth Limitations of Microwave Transistor Amplifiers

Gain-bandwidth limitations of broad-band single-stage microwave transistor amplifiers are related to a simple transistor circuit model, to constraints on characteristic impedance in a distributed-element equalizer, and to the line lengths of this equalizer. The gain-bandwidth performance of commensurate distributed-element equalizers is compared with the performance of a lumped-element equalizer, and four distributed-element design examples are presented, including two commensurate equalizers and two computer-optimized networks.     

高速电路设计中信号完整性的反射分析

针对高速电路设计中信号完整性的问题,文中通过对高速电路中传输线等效电路的分析,从理论及计算角度给出了信号反射现象的形成原因。介绍了两类常用的抑制反射的端接方案, 阐述了6种阻抗端接匹配方法消除反射的原理。通过Cadence公司的SpecctraQuest仿真工具对点对点信号传输网络进行了反射仿真,给出了在不同阻抗匹配方式下的仿真测试结果。结果表明,适当的阻抗匹配方式可以改善信号传输的反射现象。     

Real frequency wide-band impedance matching with nonminimum reactance equalizers

This paper describes two modifications to the real frequency technique of broadband impedance matching. A fundamental limitation of all broadband matching techniques is that the real and imaginary parts of the equalizer impedance must be related by the Hilbert transform. It is shown that additional degrees of freedom in the Hilbert transform, and thus a better match, can be obtained by employing equalizer impedances with nonminimum reactance and by optimizing the equalizer resistance outside the stated bandwidth. Examples will be presented for a thin wire dipole antenna.     

Variation tolerant design methods for wideband low noise amplifiers

In this paper, we develop design techniques for reducing the impact of manufacturing variations on wideband low noise amplifiers (LNA). Utilizing an efficient modeling and circuit optimization method, we investigate the sensitivity of LNA performance metrics to process variations and determine that the input impedance matching is particularly sensitive to perturbations in component values. To mitigate the impact of process variations on the input impedance matching, we add additional circuit elements and tunable capacitors to dynamically compensate for manufacturing variations after fabrication. The results indicate that the proposed design techniques can increase manufacturing yield by up to one order of magnitude for input impedance matching with only a 14% increase in noise figure.     

LDMOS宽带功率放大器匹配电路设计

针对LDMOS宽带功率放大器匹配电路设计,提出了一种快速、有效的方法.采用多节并联导纳匹配法得出宽带匹配电路的初始值后,利用ADS软件对匹配网络的S参数进行优化.仿真结果为:在频率范围为1.3 GHz～2.3 GHz内,两端口的反射系数均小于-25 dB,匹配网路的传输系数接近0 dB.为实现更好的阻抗匹配,再用ADS...     

宽带圆极化整流天线的研究与设计

针对空间微弱射频能量收集,提出了一种宽带圆极化整流天线,其主要由射频能量接收天线和多频整流电路构成.为了获得宽频带特性,接收天线的辐射贴片采用对数周期交叉偶极子.同时,两对交叉偶极子均由环形的90°相位延迟线连接,且相互正交,从而实现天线的圆极化特性.多频整流电路由两个单阶电压倍压整流电路并联而成,为了提高整流电路的性能和效率,引入了具有两个枝节的新型阻抗匹配电路.仿真结果表明:接收天线的阻抗带宽和3 dB轴比带宽分别为1 100 MHz和350 MHz;多频整流电路的功率灵敏度达到-35 dBm,最大RF-DC整体转换效率可达76.5%.在辐射强度为6.02 μT,负载电阻为700 Ω时,测得整流天线负载端的输出电压约为139 mV,因此该整流天线适用于低功率射频能量收集应用.     

弹光调制器压电晶体阻抗匹配特性的研究

根据弹光调制干涉具的工作原理,利用等效电路的方法,对压电晶体的阻抗特性进行了分析与计算,推导出了压电晶体与信号源间的理想匹配条件,得出了匹配网络中电感、电容的理论关系.根据理论关系,在信号源与压电晶体间作相应的阻抗匹配,搭建系统并进行相关实验验证.实验结果表明,通过该阻抗匹配网络,可使弹光调制干涉具的振动性能达到最佳,提高了驱动控制器的电品质因数,进而将弹光调制干涉具调制光程差提高了40％,达到了提高弹光调制傅里叶变换光谱仪光谱分辨率的目的.     

Matching of an impedance to a feeder with the help of Γ sections consisting of reactive LC elements with finite Q factors

Relationships for calculation of the elements of ?? sections, which consist of reactive LC elements with finite Q factors and are used for matching of the load impedance to the resistance of a generator are derived. Recommendations on the choice of a particular type of the ?? section out of eight possible design versions for an arbitrary position of the point representing the load impedance on the Smith chart are given. It is shown that, in the case of a high level of the load standing-wave ratio (more than 100), the dissipative insertion loss of a matching ?? section with imperfect elements experiences substantial oscillations, which depend on the phase of the reflection coefficient and the relationships between the Q factors of reactive LC elements. As an example, the results on matching of small electric and magnetic monopoles with lengths of (0.2?C0.9)??/4 to a circuit with a characteristic impedance of 50 ?? are presented.     

单相高增益准Z源逆变器研究

文中提出了单相高增益准Z源逆变器拓扑结构,分析了该逆变器的电路拓扑、采用的控制方式和各工作状态,给出了主要电路参数的设计依据,得出了重要结论。在所提出逆变器电路拓扑结构中,高增益阻抗网路由传统准Z源逆变器的阻抗网络后附加级联额外的一级形成。1kW 100VDC/220V50HzAC单相高增益准Z源逆变器样机实验结果表明,所提出逆变器具有电路结构简单、升压能力强、开关管电压应力小、输出波形质量好等优势,在新能源发电领域具有更广泛的应用前景。     

Microwave Power GaAs FET Amplifiers

The development of broad-band microwave amplifiers using state-of-the-art GaAs power FET's covering the 6-12-GHz frequency band is presented. A unique circuit topology incorporating an edge-coupled transmission line section for both impedance matching and input/output dc blocking is described. The microstrip circuit design of an X-band 1-W 22-dB-gain GaAs FET amplifier is also discussed. Microwave performance characteristics such as intermodulation, AM-to-PM conversion, and noise figure are included.