两节传输线阻抗变换器的分析与设计

阐述了一个两节理想传输线阻抗变换器的设计方法,该传输线阻抗变换器能以任意两个频率点对任意的纯电阻负载实现阻抗匹配。在给定的约束条件下,通过对该阻抗变换器方程进行解析,得到所有的设计参数,并对所设计的阻抗变换器进行仿真分析,结果显示了该设计方法的正确性。     

任意频率比双频率阻抗变换器

讨论了双频阻抗变换器的设计方法 ,该阻抗变换器能在两个任意的频率点对任意电阻性负载实现理想的阻抗匹配 ,通过对两节传输线匹配方程的严格解 ,得到了双频阻抗变换器的精确设计公式 ,对用该方法设计的阻抗变换器性能进行了仿真分析 ,仿真结果显示了该方法的有效性 ,其结果可用于实际的设计问题。     

宽带阻抗匹配变换器的设计

为解决宽带阻抗匹配变换器设计的复杂问题,克服频率展宽对阻抗变换器的影响,设计了一种两节λ/4宽带阻抗变换器,并分析了宽带阻抗变换器的频率特性。利用微波网络级联理论分析了两节宽带阻抗变换器的设计过程,推导了频率特性的数学模型,最后对模型进行仿真实验。结果表明可以找到最佳转换比(负载与特性阻抗之比)使得频率特性得到改善程度,适用于宽带阻抗匹配变换器的快速设计。     

传输线变压器相位补偿技术及其应用

传输线变压器是在短波和超短波频段使用广泛的重要器件,根据传输线变压器原理设计制造的器件具有结构紧凑、功率容量大、频带宽、损耗小等优点.该文研究了利用慢波线原理和相位补偿技术克服传输线变压器对于传输线电长度的限制,使其适用频率向s波段以上扩展的方法.文中给出了1:4阻抗变换器电路的传输损耗和高低端输入阻抗理论公式并对其进行了讨论.对所设计的S波段1:4阻抗变换器及功率合成器进行了仿真分析并设计制作了实物.仿真和实测结果表明,利用慢波线原理和相位补偿后的传输线变压器能够适用s波段及以上微波器件.     

一种高变比宽频带短传输线段阻抗变换器

分析了一种短传输线段阻抗变换器的原理、频带宽度、变换比和电长度,给出了设计实例.从而说明这种短传输线段阻抗变换器适用于高变比阻抗变换,与1/4波长传输线阻抗变换器相比,其频带宽,电尺寸小.     

计及特性阻抗不连续性的多频带多节变换器优化设计

 本文设计了计及特性阻抗不连续性的两频两节及三频三节变换器.基于理想传输线模型和微带传输线理论,建立了计及微带线"台阶"效应的设计方程,采用遗传算法实现优化设计,取得了在纯电阻源阻抗和负载阻抗以及随频率变化的源阻抗和负载阻抗两种情况下的两频两节及三频三节阻抗变换器设计参数.用ADS(Advanced Design System)商用软件对基于上述设计参数的微带电路进行电磁仿真的数值结果显示了该设计的有效性.     

超短波宽带阻抗变换器的设计与实现

基于传输线变压器原理的超短波超宽带阻抗变换器,在短波和超短波电路中具有十分重要的地位。这类器件 具有相对带宽宽、尺寸小、传输效率高的优异性能。本文采用铁氧体磁环设计了一款基于传输线变压器原理的宽带Ruthroff 型1：4 阻抗变换器和一款宽带四路功率分配器。从测量结果可以看出,两款器件在2 MHz 到500 MHz 的大部分频带范围内, 回波损耗均小于-14 dB,传输损耗均小于1 dB。研究成果对于正确理解传输线变压器器件工作原理、合理确定参数诸元、实现 预期频带特性等方面具有一定参考价值。     

级联传输线阻抗变换器的计算机综合设计

本文运用散射矩阵方程导出了两端口无耗匹配网络条件,推导了级联传输线阻抗变换器的设计公忒。给出了计算机综合设计程序框图。最后,给出了两个设计实例,且与1/4波长阻抗变换器进行了比较。     

非常规变比阻抗变换器的设计与实现

在常规1∶4变比平衡-不平衡传输线阻抗变换器的基础上,分别分析了1∶n(2≤n＜4)和1∶n(4＜n≤12)非常规变比宽频带阻抗变换器的设计思想,并给出了附加绕组长度的确定公式.同时明确了绕制非常规变比阻抗变换器的注意事项和对于补偿电路的确定方法.最后通过两个实例验证了文中设计思想的有效性.     

介绍一种阻抗变换器的简单计算方法

阻抗变换器是传输线阻抗匹配的常用方法,但宽波段匹配需进行较复杂计算。本文所介绍的一种阻抗变换器的简单计算法中,首先简要地叙述了在直角坐标系上对传输线作宽频段阻抗匹配的计算原理。通过保角变换方法推导出在史密斯阻抗圆图上进行匹配的一般表示式,绘出一套在史密斯阻抗圆图上的阻抗匹配图,并举出一些例子以说明其使用方法。     

30～512MHz,100W线性功率放大器极间匹配设计

设计了一种独特的极间匹配网络,使驱动放大器的输出阻抗直接匹配到末级放大器的输入阻抗,而不通过极间50Ω匹配转换。应用这种极间匹配网络,提高了30～512 MHz,100 W功率放大器的线性输出功率和效率,同时简化了匹配网络,减少了匹配元件,缩小了功率放大器的体积。这种极间匹配网络是通过集中L、C匹配网络与宽带同轴传输线变压器相结合实现的。应用ADS软件模拟以及计算集中L、C元件的值和同轴电缆的长度,使设计的极间匹配网络在近十个倍频程的频带内获得最佳性能。     

Engineering Design Method of Energy Coupler and Impedance Transformer for Millimeter Wave Tubes

The engineering design method of heliz-waveguide and rectangular coupled cavitiy-waveguide energy coupler employed in millimeter wave tubes is described. Experiments show that, the former has broadband matching character )VSWR is less than 2 at 26 - 40GHz). And the later has small reflection (VSWR is less than 1.5 at 34-37.5 GHz). Optimum design method of multi-section and linear taper waveguide impedance transformer is also given in this paper. These impedance transformers can operate at wide frequency range in microwave and millimeter wave band. The design method and examples of couplers and impedance transformers can be referred for tube designers.     

Basic RF Characteristics of the Microstrip Line Employing Periodically Perforated Ground Metal and Its Application to Highly Miniaturized On-Chip Passive Components on GaAs MMIC

In this study, highly miniaturized on-chip impedance transformers employing periodically perforated ground metal (PPGM) were developed for application to broadband low-impedance matching. In order to realize a broadband operation by using an equal ripple transfer characteristic over a passband, a three-section transformer was designed by mapping its reflection coefficient to the Chebyshev function. The three-section transformer showed a good RF performance over a broadband (1.5–13 GHz) including ultra-wideband. The size of the three-section transformer was 0.129$hboxmm^2$, which is 2.3% of the size of the transformer fabricated by a conventional microstrip line. Using the PPGM structure, a highly miniaturized on-chip Wilkinson power divider with a low port impedance of 13$Omega $was also developed, and its size is 0.11$hboxmm^2$, which is 6% of the size of the one fabricated by the conventional microstrip line. In addition, in this study, the PPGM structure was theoretically characterized using a conventional capacitive loaded periodic structure. Using the theoretical analysis, basic characteristics of the transmission line with PPGM were also investigated in order to evaluate its suitability for application to a development of miniaturized on-chip passive components. According to the results, it was found that the PPGM structure is a promising candidate for application to a development of miniaturized on-chip components on monolithic microwave integrated circuits.     

Mixed lumped and distributed network applied to superconductingthin-film broadband impedance transforming

In this paper, a detailed analysis of the properties of mixed lumped and distributed (MLD) lossless elements is first carried out. It is found that such networks can be used as extreme impedance transformers between source and load impedances without large variations in wave impedance values. Then, the lossy transformation technique (LTT) is extended to the design of MLD lossy networks. Finally, to exhibit the practical use of the new method, three examples are given for transforming extremely low input impedance of a superconducting device to a 50 Ω microwave system with the MLD networks. The outstanding advantage using this method is that transformers can be made considerably shorter than by common methods and still physically realizable. The length of the building element is reduced from λ/4 to λ/16     

基于GaN HEMT 多倍频程高效率功率放大器设计

使用GaN HEMT 功率器件,设计了一款多倍频程高效率功率放大器。利用负载牵引技术分析输入功率、偏置电压、工作频率对功率器件输出阻抗的影响,从而寻找出满足宽带性能的最优阻抗区域;输入、输出匹配网络采用了切比雪夫多节阻抗变换器的综合设计方法,很好地拓展了匹配网络的带宽性能,从而实现了0. 8 ~4. 0 GHz(相对带宽133%)多倍频程高效率功率放大器电路。连续波大信号测试结果表明:在0. 8 ~ 4. 0 GHz 的频率范围内输出功率为39. 5 ~42. 9 dBm,漏极效率为54. 20% ~73. 73%,增益为9. 4 ~12. 0 dB。在中心频率2. 4 GHz 未利用线性化技术的情况下使用5 MHz WCDMA 调制信号测试得到邻近信道泄漏比(ACLR)为-27. 2 dBc。设计的工作频率能够覆盖目前主要的无线通信系统GSM900M、WCDMA、DCS1800 LTE、PCS1900 LTE、3. 5GHz WiMAX 以及下一代移动通信系统(5G)等。     

Computer Optimization of Inhomogeneous Waveguide Transformers

The problem of designing broadband multisection stepped rectangular waveguide impedance transformers, when the input and output guides have different cutoff frequencies but propagate the same mode, is formulated in general terms for direct optimization by digital computer. The formulation is sufficiently flexible to allow nonideal junction discontinuity effects and mismatched terminations to be taken into account during optimization. Constraints placed on the width, height, or length of any section need be dictated only by considerations for dominant mode propagation and the requirement of small (but not necessarily negligible) junction discontinuities. The objective of the present formulation is a minimax equal-ripple response over a predetermined frequency band satisfying the constraints selected for the particular problem. The ripple search strategy to locate the maximum reflection coefficient within the band and the razor search strategy to minimize it, as described by Bandler and Macdonald in another paper, were employed. Constrained optimum equal-ripple solutions to examples previously published by Young, Matthaei et al. and Riblet are presented. They demonstrate the considerable improvements made possible by the present formulation with regard to performance, reduction in number of sections, and physical size. The approach used in this paper should also find application in the design of broadband microwave matching or equalizing networks consisting of noncommensurate components and for which exact synthesis techniques may be unavailable.     

Design of impedance transformers by the method of least squares

The method of least squares is applied to the theory of small reflections of transmission lines to develop numerical algorithms for the design of stepline and tapered line impedance transformers to match two impedances over a frequency band. The transformer characteristic impedance function is expanded by polynomials, pulse functions, approximate operators, and piecewise linear functions to construct an error function for the input reflection coefficient which, after minimization, gives the line impedance and length. The computer programs could be used to design a transformer under the specified conditions and then to optimize the design under the constraints of a problem     

Design of a compact broadband microstrip patch antenna with probe feeding for wireless applications

In this paper the design and development of a compact broadband probe-fed Microstrip patch antenna for bandwidth improvement and antenna size reduction in a single design is proposed. The well-known technique of effective substrate thickness increment is performed to improve the impedance bandwidth, whereas for size reduction the electrical length of the conducting patch has been increased. A compact probe-fed inverted U-shaped microstrip patch antenna with a W-shaped ground plane has been designed and the experimental results are presented.     

Small Elliptic-Function Low-Pass Filters and Other Applications of Microwave C Sections

A type of elliptic-function low-pass filter that is easy to design and construct, has low passband loss, and is very compact is described. With simple scaling and a limited number of standard parts, a broad range of cutoff frequencies can be obtained. Experimental results are presented for three filters with cutoff frequencies of 0.75, 1.0, and 1.5 GHz. Each filter occupies a volume of about 0.5 in/sup 3/. A physical interpretation of the conventional scaling transformation S =S'/ /spl Omega//sub c/' is given for networks containing unit elements. Use of this transformation is shown to yield scaled networks containing microwave C sections rather than unit elements. Applications to broad-band impedance transformers are given and other possible applications are suggested.     

A minaturized broad-band MMIC frequency doubler

A miniaturized broadband balanced MMIC (monolithic microwave integrated circuit) frequency double, composed of a common-gate FET and a common-source FET directly connected to each drain electrode, has been proposed and demonstrated. The doubler is designed and fabricated as a miniaturized function module using a conventional two-gate FET configuration, active trapping, and active impedance matching. The doubler design has been performed through phase error estimation, gate width optimization, and gate-source voltage optimization. The phase error estimation in a nonlinear condition has eliminated phase error compensation circuits. The fabricated chip size is only 0.5 mm×0.5 mm, which is about 1/10 the area of previously reported doublers. A conversion loss of 8-10 dB, a fundamental frequency suppression better than 17 dB, and an input return loss better than 8 dB are obtained in the output frequency range from 6 to 16 GHz. The broadband doubler as a miniaturized MMIC function module can be applicable to small-size oscillator MMICs and multifunction MMICs