基于多层带状线谐振子结构的带通滤波器设计

采用多层耦合带状线谐振子结构和高介电常数材料实现带通滤波器的微型化设计.谐振子的谐振频率采用Sonnet软件计算得出,谐振子的耦合系数采用Sonnet和HFSS仿真计算得到,最后采用HFSS进行结构调整以实现设计优化.该方法设计过程简便易行,得到的滤波器结构简单,易于制作.采用该设计方法设计并制作了一个L波段的5阶低温...     

新型双频窄带带通滤波器的设计

提出了1种新型双频窄带带通滤波器,由1段1/4波长的均匀阻抗线以及1/2波长的U型阶跃阻抗谐振器组成,输入输出采用抽头式.所设计滤波器中心频率为2.4/5.6 GHz,为无线通信系统中的常用频率.该滤波器的带外有3个传输零点的引入,增强了通带隔离度以及阻带的抑制特性,带内回波损耗低于-0.3 dB.双频窄带带通滤波器的...     

混合耦合电调滤波器设计

设计了一款调谐范围为1200~1800MHz的电调滤波器。在传统梳状线电调滤波器的基础上,通过折叠变化引入了级间电磁场混合耦合使其在传输特性曲线低频端产生了两个传输零点,提高了带外抑制能力。引入的源负载耦合技术使传输零点向通带靠拢,进一步改善了滤波器的带外抑制能力。经测试,该滤波器的带外抑制度达到50dBc(1000MHz)、30dBc(2000MHz)。     

高谐波抑制隔离-滤波集成磁性器件仿真设计

针对5G通讯中磁性器件高二次谐波抑制的发展需求,通过对传统滤波器进行分析,结合HFSS电场软件对传统的阶梯阻抗谐振器(SIR)滤波器进行结构优化和仿真分析.在满足小尺寸要求的前提下实现了器件带内、带外优异的微波性能.通过与铁氧体隔离器进行集成优化,最终设计了一款带内频响特性好、带外抑制度高的集成磁性器件.器件实测性能指标满足项目技术要求:带内工作频率:f=24～27.5 GHz,带内回波损耗:≥20dB,带内隔离度:≥20 dB,带外二次谐波抑制:≥35 dB.     

225～512 MHz双腔数字调谐滤波器设计与实现

针对超短波无线通信系统对载波频率可调性、高选择性的需要,设计了一种同轴双腔数字调谐滤波器.该腔体滤波器在端口激励采用线圈开环耦合以增大传输带宽,双腔之间装配金属铜片调整耦合系数大小,滤波器中的控制电路板使用PIN管选通不同电容对滤波器中心频率实现大范围调谐.实测性能:工作频率为225～512 MHz;插入损耗≤6dB,3dB带宽为1％～2％;电压驻波比≤1.5.测试结果显示该滤波器指标优良、仿真与实测一致性较好,设计方法对于数字调谐滤波器的设计具有参考意义.     

具有寄生通带抑制的微带带通滤波器的设计

寄生通带的抑制程度是微带滤波器的关键性能参数之一.介绍了1种能够在较宽频带内有效抑制寄生通带的设计方法,通过将带通滤波器和低通滤波器级联、联合仿真优化,最终得到在通带的二倍频与三倍频区域都具有足够抑制的微带带通滤波器原型.给出了具体的设计原理,以及使用ADS和Ansoft Designer的设计步骤与流程.最后的实测结...     

新型开环耦合谐振滤波器的设计与应用

为了满足日新月异的无线通信对小型化带通滤波器的要求,针对传统类型滤波器存在线性度、矩形系数、插入损耗、体积等方面的问题,笔者介绍了一种通过在微带开环谐振滤波器中引入交叉耦合,产生一对传输极点,从而提高滤波器选择性的滤波器设计方法,并讨论了这种滤波器的综合方法和实现流程。实际设计了一个六阶开环谐振滤波器,并给出了全波仿真结果。分析和仿真都表明这种滤波器具有体积紧凑、选择性高的优点。     

供电与通信复用电路带通滤波器设计

供电与通信复用电路系统接入电网或者非线性负载时,噪声干扰不利于信息准确解调,为解决这一问题,设计一种应用于复用电路的带通滤波器.首先对巴特沃斯滤波器和切比雪夫滤波器性能进行比较,重点研究了巴特沃斯滤波器响应与级数之间的关系,最后提出了这种带通滤波器参数设计方法.通过实验验证了该带通滤波器在体现基波频率包络变化的同时可有效抑制噪声干扰,提高了通信解调电路的可靠性.     

截止频率为200MHz的LTCC叠层低通滤波器的研制

在对LTCC多层结构电感和电容元件研究的基础上,由对L、C的参数的控制,通过三维场仿真软件HFSS对LTCC滤波器三维结构模型进行仿真模拟和参数提取,设计制作了截止频率为200MHz、在600MHz带外抑制大于25dB的0805尺寸无源集成低通LC型滤波器.仿真结果与样品的测试结果基本吻合.实验证明通过合理的设计,用H...     

基于方形开环的双模滤波器设计

在传统方形开环谐振器的基础上,设计了一种新型的双模微带滤波器,该滤波器包含两个方形开环谐振器,在每个传统谐振器内部添加微带支路结构,通过微扰来实现频响特性的改善,由仿真结果可以看出,该设计的带内特性良好,带内波纹小于0.3dB,通带边沿均插入了传输零点,且传输零点处的S21〈40dB,截止边沿陡峭,实现了6%的相对带宽,整个滤波器的尺寸大小约为30mm×20mm,改进后的结构与传统结构相比降低了0.5GHz的中心频率,相对减小了16%的面积,进一步实现了小型化。     

Microwave filters with nonperiodic transmission characteristic

A microwave filter with nonuniform-coupled transmission lines is suggested. In contrast to known transmission-line microwave filters the transmission characteristic does not change periodically with frequency. The synthesis procedure shown reduces the design problem to the known synthesis of directional couplers with nonuniform coupling factor. A table of calculated coupling factor values of the microwave filter with an equi-ripple passband of 0.05 dB up to 1 dB and an equi-ripple stopband of 60 dB is given. A practical design example shows good agreement with theoretical results.     

Electronically Tunable Filters

In this article, a brief introduction to the development of tunable filters was given. A classical design technique based on a combline filter approach was shown, where minimum degradation in passband performance could be obtained across a broad-tuning range. The fundamental disadvantages associated with the conventional resonator tuning approaches were also discussed, recognizing the importance of developing new techniques for realizing tunable microwave filters. It was shown that there is a possibility in realizing an electronically reconfigurable microwave filter based on parallel- coupled switched-delay lines, which possesses the important property of maintaining constant absolute bandwidth over almost an octave of tuning bandwidth. Furthermore, the filter has the ability to incorporate active switching elements in the filter circuit, without sacrificing its loss and linearity performance. With the exceptional linearity performance and power handling capability, the filter is readily adapted to poor environments. Although the use of p-i-n diodes as switching elements would result in large dc consumption, the approach could also be readily adapted for use with any switches, such as pHEMT or RF MEMS switches, to achieve extremely low power consumption. The integration of switchable couplings to enable both bandwidth and center frequency to be reconfigurable would be an enhancement.     

加厚膜片带通滤波器的仿真设计

随着频率应用的提高,传统的电感膜片耦合波导式带通滤波器已经不能适应机加工的现有能力和精度要求.通过增加膜片的厚度可以降低对机加工能力的要求,同时也易于满足设计精度的要求.本文通过CAD仿真设计,由传统的薄电感膜片带通滤波器设计原理演绎出加厚膜片带通滤波器的设计原理,并且通过对单节电感膜片和多级电感膜片级连滤波器电路特性的分析,得出了它们在滤波器中级联时对电性能贡献的共性.本文采用高频电磁场仿真进行计算,优化具体的电尺寸,给出了具体的设计实例.实测的结果和理论设计仿真的结果一致性较高.这种加厚膜片的滤波器能够扩展到毫米波频段应用,而且易于加工;运用S参数的等效性和高频电磁场仿真软件可以方便、准确地设计出易于加工、性能良好的滤波器件.这种设计方法同样适用于其他微波器件的设计(如电感销钉滤波器等).     

中频数据采集前端电路的设计

首先介绍了中频采样系统中前端抗混叠滤波器技术指标的确定方法,重点论述了采用ANSOFT公司的Designer微波仿真软件设计抗混叠滤波器的方法,以及如何对设计结果进行优化。目前,采用该设计方法设计的电路已经成功应用于一种便携式频谱分析仪的设计中,经验证,其技术指标达到了预先的设计要求。     

可调窄带滤波器中低噪声放大器的优化设计

低噪声放大器(简称低噪放)是射频接收前端中的重要部件。设计性能优良的低噪声放大器能够极大的提高通信系统接收机灵敏度和通信质量。本文对微波放大电路的设计方法进行了探讨,并在ADS软件界面上进行了微波窄带滤波器低噪声放大器的优化设计。     

Selective,constant delay wave digital filters

A wave digital filter design method is discussed which produces good selectivity and flat delay characteristics. The filter is designed in the microwave domain with monotonic stopband response using Carlin and Wu's technique for minimum-phase linear phase commensurate line transducers, then realized in the digital domain with Fettweis relations. A comparison is made of frequency response sensitivity to multiplier coefficient truncation between this wave filter and some FIR's, all with approximately the same number of multipliers. The cascade realizations of the FIR's show considerable passband amplitude response deterioration due to coefficient truncation, whereas the direct realizations for the FIR's show significant deterioration of stopband amplitude response owing to coefficient truncation. Coefficient truncation for the wave digital filter caused relatively small deterioration of both passband and stopband amplitude responses as well as small distortion of the flat delay characteristic in the passband.     

Advanced filter design technique based on equivalent circuits and coupling matrix segmentation

This paper presents a technique for the efficient design of bandpass waveguide microwave filters using a segmentation technique applied to an equivalent circuit. The technique is based on first developing an equivalent circuit that synthesizes the desired transfer function. Then, the different parts of the real physical structure are optimized by segmenting this equivalent circuit. The technique was originally developed for in‐line filters, and the main contribution of this paper is in the combination of this technique with the coupling matrix formalism. In this way, we adapt for the first time this design strategy to the design of complex coupling topologies, beyond the in‐line configuration. As an example, a complex sixth‐order dual‐mode filter, implemented in all‐inductive waveguide technology, is designed using the new coupling matrix segmentation technique, showing the effectiveness of the presented theory. A prototype of the filter has been manufactured, and the accuracy of the design technique is verified by measurements on the real prototype.     

Reliable reduced cost modeling and design optimization of microwave filters using co‐kriging

A reliable methodology for accurate modeling of microwave filter is presented. Our approach exploits co‐kriging that utilizes low‐fidelity and high‐fidelity electromagnetic simulation data and combines them into a single surrogate model. Densely sampled low‐fidelity data determine a trend function, which is further corrected by sparsely sampled high‐fidelity simulations. Low‐fidelity electromagnetic data are also enhanced by using a frequency scaling to reduce its misalignment with the high‐fidelity model. With our method, accurate models can be obtained at a fraction of the cost required by conventional approximation models that are exclusively based on high‐fidelity simulations. Three examples of microstrip filters are considered for verification purposes. We also provide comparisons with conventional approximation models and include an application of co‐kriging models for filter design optimization. Copyright © 2013 John Wiley & Sons, Ltd.     

Microwave engineering

A brief history of microwave engineering is given. The impact of computer-aided design and monolithic microwave integrated circuits on microwave design is examined. The career potential of microwave engineering is discussed, along with suggestions for related studies that would be useful to the microwave engineer     

Thermal analysis,design, and implementation of an L-band high-power stepped impedance low-pass filter

This paper presents high power, thermal analyses, and implementation of a stepped impedance high-power low-pass filter (LPF). A comprehensive model and analysis have been developed for the design and simulation of the LPF. In this analysis, power handling capacity and breakdown-voltage are discussed, and the effects of critical points are considered. The attenuation due to conductor and dielectric losses is also studied. The novelty of our approach lies in employing theoretical analysis to estimate the power-dissipation of the filter based on the proposed equivalent circuit. An accurate method is also introduced to calculate attenuation in the filter's elements. Thermal analysis to obtain accurate temperature profiles is done for the first time based on the electro-thermal simulation. Consequently, an effective cooling method is used to spread heat across the entire filter. Finally, the filter was implemented and tested to operate at L-band with handling 8 kW peak and 800 W average power. The insertion-loss is less than 0.27 dB, the stop-band attenuation is more than 60 dB, and the return-loss is better than 15.7 dB. The filter is capable of tolerating produced heat without any destructive effects at a maximum temperature of about 200°C above ambient. The theoretical analysis and experimental results show that the LPF is suitable for high-power microwave applications.