微波部件、毫米波部件

0619870一种大功率宽频带低损耗定向耦合器的设计与实现[刊,中]／田丰／／电子科技．-2006,(4)．-47-50(D)根据传输线变压器串并联同时耦合的原理,设计了一种13dB铁氧体定向耦合器,该定向耦合器是用漆包线绕在射频铁氧体磁芯上做成。具有尺寸小、结构简单和频带宽等优点,工作范围在100～400MHz。对其参数进行了理论计算和测量,满足设计要求。经过实际应用,验证了设计方法的可行性。参3     

平行耦合线定向耦合器的设计

阐述了平行耦合线定向耦合器的工作原理和设计过程.根据耦合微带线和耦合带状线的主要特征,分别设计了频率为2.5GHz的平行耦合微带线定向耦合器和平行耦合带状线定向耦合器.根据给定耦合器的技术指标,确定耦合器的类型、结构.利用ADS软件环境设计了平行耦合线定向耦合器的电路模型,并对定向耦合器的S参数进行仿真、优化,已达到预期的设计要求.由仿真结果可以看出,在频带范围内,耦合带状线定向耦合器的耦合性能优于耦合微带线定向耦合器.     

非对称定向耦合器设计

定向耦合器是微波通信领域必不可少的元件之一.平行耦合与分支线耦合是定向耦合器的两种基本形式.重点研究非对称多节定向平行耦合器的设计.根据设计的结构和尺寸,通过HFSS软件进行耦合器结构的仿真.仿真结果表明,设计的定向耦合器可以实现1～4 GHz宽频带下20 dB的耦合度.另外,仿真验证了节支长度对耦合度并不敏感.     

高功率三阶3dB介质定向耦合器的分析与设计

根据定向耦合器的工作原理及要求,利用HFSS软件分析并设计了一款以空气为介质的三阶3 dB定向耦合器.并在此基础上,使用具有高电压击穿特性的三氧化二铝陶瓷片作为耦合介质,分析并设计了一款高功率三阶3 dB介质定向耦合器.此介质耦合器在保证足够带宽的前提下,能够提高耦合器的耐压性能,实现了定向耦合器的高功率耦合,从而可以...     

利用复合左右手传输线实现的两种平行耦合线定向耦合器

采用紧凑的复合左右手传输线模型实现了两种新型平行耦合线定向耦合器.第一种定向耦合器为六端口双定向耦合器,形式为右手传输线/复合左右手传输线/右手传输线,通过调整传输线与传输线之间的距离,实现一分三等分功率分配器的功能;第二种定向耦合器是在普通定向耦合器中,用部分复合左右手传输线代替右手传输线,通过调整它们之间的比例,可以使得耦合端和输出端的输出相位相等.设计的两种定向耦合器,均已通过实测验证.     

非均匀传输线定向耦合器的研究

给出了非均匀传输线定向耦合器的通用计算公式。并指出这种定向耦合器有两种特殊的用途:小型定向耦合器和超宽带定向耦合器。对每一种情况都给出了设计实例.并与全波电磁场分析进行了比较,结果是吻合的。     

一种新型双层微带定向耦合器

提出了一种新型双层微带结构的3 dB定向耦合器.此耦合器由两层带有耦合缝隙和寄生单元的介质板背对背放置.通过增加耦合面积和引入寄生单元补偿电容起到了均衡奇、偶模相速提高了耦合度,实现了宽频的3 dB紧耦合.通过优化设计,在频带范围内,此双层微带定向耦合器的定向性优于普通的耦合微带线定向耦合器.设计结果在450～860 ...     

微波部件、毫米波部件

0205951一种高定向性宽频带微带定向耦合器的研究[刊]/凌天庆//微波学报.—2001,17(4).—84～91(L)常规微带耦合器的定向性比带状线耦合器的定向性差,有多种方法可以改善微带耦合器的定向性。本文在分析了1/4波长微带耦合器接补偿电容时的带宽和定向性的基础上,提出了一种高定向性、宽频带微带耦合器的设计方法。实验证明此方法达到了预期的效果。参8     

超宽带多节定向耦合器设计

介绍了一种简单易行的多节定向耦合器设计方法.采用平行耦合线的分析理论得到了多节定向耦合器的耦合度通用表达式,再通过耦合度带内波纹波动最小条件求解得到耦合器的设计参数.最后给出了一个设计实例,耦合器在工作带宽1～4 GHz内,插损小于0.4 dB,耦合度带内波动小于±0.25 dB,设计数据和实物测试数据具有很好的一致性.     

磁耦合定向耦合器仿真设计

在分析波导中场模式基础上,通过仿真计算和优化,得出影响定向耦合器磁耦合的主要因素,并在此基础上提出利用磁环耦合设计双耦合度定向耦合器和可变耦合度的定向耦合器的设想.通过仿真,所得结果和理论分析相吻合,证明了设计方案的可行性.     

Tunable characteristics of ferrite composite right/left handed coplanar waveguide coupled line coupler – Measurement and experimental verification

This paper presents the experimental verification of the tunable characteristics of a ferrite composite right/left handed coupled line coupler. The coupler is designed using two coupled CRLH-CRLH transmission lines. The coupler is designed to demonstrate equal through and backward coupling. The novel coupler has been designed and realized in coplanar waveguide configuration on a ferrite substrate. The tunable characteristics are achieved by changing the applied DC magnetic bias to the ferrite substrate. The measurement results reveal that the coupler’s fractional bandwidth can be tuned from 29% to 69% by varying the applied DC magnetic bias from 1000 Oe to 1750 Oe. Within the tunable bandwidth, the maximum backward coupling is −5 dB. The coupler has high forward coupling isolation, close to −30 dB at its centre operating frequency. In addition to its tuning capability, the coupler has the advantages of its compact size; it has the length of 11.5 mm and not-so-tight line separations of 2.5 mm. Furthermore the coupler only requires low DC magnetic bias.     

Wide-band rotary transformer—Unbalanced current analysis

Performance of a wide-band rotary transformer with approximately 1000:1 bandwidth (80 kHz-80 MHz) is described. A previous paper [1] gave theoretical analysis and experimental results based upon lossless balanced, transmission line theory. This paper extends the results to the case of a shielded transformer, and uses a combination of balanced and unbalanced line theory to account for losses and predict frequency response. Theoretical results are confirmed by data measured on a prototype coupler.     

Impedance formulas for planar magnetic structures with spiralwindings

It is well established that magnetic components may be reduced in size by operating at high frequency. Miniaturization of magnetic components is ideally suited to microelectronics technologies such as thick films, which lend them to planar geometries. This paper describes new analytical models, which predict inductance- and frequency-dependent eddy-current losses in magnetic substrates. Prototype devices were fabricated by a thick-film process with four layers of conductors on a single ferrite substrate and in a sandwich configuration, consisting of conductors between ferrite slabs. The prototype devices were tested in the frequency range 10 kHz-100 MHz. The measurements confirm the validity of the analytical models. Simulation with finite-element analysis was employed to identify different sources of losses: eddy current losses in ferrite substrates; proximity effect losses in conductors; and dielectric losses     

A novel rat race coupler design for dual-band applications

This letter presents a novel and compact rat-race coupler design that can operate at two widely separated frequency bands. It is accomplished by modifying the length and impedance of the branch lines in the conventional structure, and the insertion of two additional shunt stubs. The proposed circuit also features planar structure and low insertion loss. For verification, the measured performance of a microstrip coupler operating at 900/2000MHz are shown.     

Analysis and Design of a 3 dB Tunable Lumped-Element Directional Coupler

An analysis of a 3 dB lumped-element directional coupler(LEDC)based on arbitrary terminal impedance is described numerically.To solve the conflicted requirement for broad bandwidth and small size in LEDC,a new structure of coupler is introduced,which can significantly improve bandwidth and whose size is only 3 cm×4 cm on the conditions of the frequency domain of 410 MHz to 490 MHz.The measure results are in good agreement with simulations despite the unexpected resistor loss.     

铁氧体可变耦合器

本文介绍一种新型的微波可变耦合器，它由二端口３ｄＢ耦合反射器和内锁式铁氧体开关组成，该器件结构简单，性能可靠，可大大简化微波网络。     

基于铁氧体材料的小型螺旋天线的仿真设计

本文以法向模螺旋天线的耦合理论为基础,运用铁氧体作为磁芯,设计了一个频带范围在2-600MHz的小型宽带螺旋天线。为了得到此螺旋天线的最佳性能,对添加同轴不锈钢棒的模型进行仿真分析。研究结果显示,螺旋天线铁氧体磁芯及同轴不锈钢棒对于频带宽度及谐振点影响很大。     

Low-loss compact Butler matrix for a microstrip antenna

This paper presents the design and realization of a double four-port Butler matrix to feed a four-column array antenna with two orthogonally polarized signals (to obtain polarization diversity). The main goals of this study are the reduction of the size and the losses of the network. In order to meet those requirements, a bi-layer structure, the suspended stripline, has been adopted to support the circuit. Moreover, the complete network has been integrated in a single unit. The double four-port Butler matrix has been etched on both sides of the suspended substrate to solve the problem of the cross between the lines. The broadside suspended 3-dB directional coupler has been chosen for the design of the 3-dB hybrid coupler. In order to change the side of the suspended substrate, contactless transitions have been used. The network is designed to work within the range of frequencies of the GSM-900-MHz standard: band 880 MHz-960 MHz, center frequency f₀=920 MHz. Measured losses for a 4×4 Butler matrix are 0.3 dB     

小型化高方向性的微带双定向耦合器设计

为解决弱耦合时微带平行耦合线定向耦合器方向性低的问题,提出了适用于大功率场合的小型化高方向性微带双定向耦合器。基于传统四分之一波长平行耦合三线微带双定向耦合器结构,采用扇形微带电容加载可明显减小耦合器尺寸并增大隔离度,通过耦合边缘引入锯齿结构进一步提高了方向性。负载电阻采用扇形微带短截线接地设计,避免电气化过孔,使得加工更加简单。设计了一个中心频率为915 MHz、耦合度为20 dB 的微带双定向耦合器,利用HFSS 仿真软件对耦合器结构进行优化设计,并做了实物加工和测试。实测结果表明,在中心频率处耦合度为20.2 dB,方向性达到32.1 dB;在0.74~1.35 GHz 频带内,输入匹配良好,耦合度波动小于0.5 dB,方向性高于20 dB。     

Electromagnetic wave absorber with wide-band frequencycharacteristics using exponentially tapered ferrite

As a countermeasure of EMI or EMC, various types of electromagnetic wave absorbers are used. A wide-band design method of an electromagnetic wave absorber with using exponentially tapered ferrite, which has very wide-band frequency characteristics, is proposed and discussed. The wide-band electromagnetic wave absorber can be designed under some approximations by the theoretical model using the equivalent material constants (equivalent complex permittivity and permeability) method for the regions varying spatially in the shape of ferrite. Based on the model, wide-band electromagnetic wave absorbers with taper, which have not only excellent reflectivity frequency characteristics but also a bandwidth of 30 MHz to 2150 MHz or 2430 MHz under the tolerance limits of -20 dB reflectivity, were designed