微声薄膜耦合谐振滤波器有限元建模与仿真

针对一维等效电路仿真模型不能对滤波器振动模式进行仿真的局限性,建立了微声薄膜耦合谐振滤波器二维和三维的有限元模型,仿真分析了滤波器在对称谐振频率和反对称谐振频率下的振动模式,并通过频率响应分析得到了滤波器的S参数.仿真结果表明,采用有限元分析法可实现微声薄膜耦合谐振滤波器几何参数以及电极结构的优化设计.     

聚合物微环谐振滤波器特性的研究

利用耦合模理论,计算了聚合物微环谐振滤波器的通路和下话路的传输函数,分析了耦合系数和损耗对传输函数的影响,并推导出了谐振滤波器的谐振波长、自由光谱范围、腔的品质因子、半峰全宽和精细度等特性参数,分析了不同的滤波器结构参数(如环形半径和有效折射率)对滤波特性的影响.     

声表面波陷波器与纵向耦合结构相结合

为了消除声表面波纵向耦合谐振式滤波器高端带外邻近通带处的肩膀,该文提出将纵向耦合谐振式滤波器与声表面波陷波器相结合,用来改善其近阻带抑制。文中给出了理论模拟及实验结果。实验结果与理论模拟基本一致,验证了方案的可行性。     

基于COM参数提取技术设计SAW梯形滤波器

与耦合谐振滤波器(CRF)相比,声表面波(SAW)梯形滤波器具有插入损耗小,功率容量大和芯片尺寸小的优点。该文从COM参数提取出发,结合COM模型和P矩阵级联的方法,设计出一个中心频率约为350MHz,插入损耗仅有1.5 dB的三极SAW梯形滤波器。从样品的测试结果发现,这种基于COM模型的阻抗元滤波器(IEF)的设计思路是正确可行的。     

铌酸锂声表面波谐振滤波器

本文叙述了SAW单节谐振滤波器——双端对谐振器的设计.介绍了YZ-LiNbO_3基片上试验的SAW谐振器响应,并对结果作了分析.同时给出了用所研究的一种谐振器简单级联试作的多级耦合谐振滤波器的性能.     

2.8 GHz薄膜体声波谐振器的研究

通过采用微机电系统(MEMS)和微声电子方法,研究了硅基片上横膈膜结构薄膜体声波谐振器(FBAR).器件的串联谐振频率f_s＝2.75 GHz,并联谐振频率f_p＝2.8 GHz,插入损耗IL=-3.7 dB,并联谐振频率品质因子Q_p=260,有效机电耦合系数K_(eff)~2=4.5%.     

声表面波横向耦合谐振滤波器

介绍了横向耦合谐振声表面波滤波器的模拟方法，给出了２１８．５ＭＨｚ耦合谐振滤波器的实验结果，获得了较好的频率特性。在外电路匹配条件下，插损４ｄＢ，相对带宽０．０６％左右。     

第二类椭圆型声表面波滤波器的设计

梯形滤波器的带宽由基片的机电耦合系数决定,当基片选择后,相对带宽基本固定。该文提出了一种椭圆型声表面波滤波器,在同一基片上特别是压电性强的基片上,可灵活控制滤波器的相对带宽。由于电容比的存在,声表面波谐振器取代椭圆LC滤波器中的谐振单元后,额外的零点和极点出现在通带两侧。引入模拟退火法对各个谐振器的静态电容进行优化,得到了窄带低损耗高矩形度的滤波器。实验证明了该方法的有效性。     

AlN薄膜异质结构声波激发特性研究

该文分别开发了两种基于AlN压电材料和原子数分数为10%的Sc掺杂AlN压电材料的薄膜叠层异质谐振器。通过有限元仿真和实验对比分析了器件的频率温度性能和Sc掺杂对谐振器声激励的影响。结果表明,Sc掺杂可能会影响压电薄膜叠层谐振器所激励声波的谐振频率、机电耦合系数和对应的频率温度系数(TCF),且对所激励声波的正反谐振点的TCF影响不同。此研究在传感及滤波器件领域极具应用潜力。     

声表面波串并联谐振耦合滤波器的研制

介绍了移动电话用声表面波滤波器的市场,详细介绍了串并联谐振耦合结构式声表面波滤波器的基本原理和设计方法,同时给出了理论计算和实验结果,实验器件的插入损耗为2.6dB,带宽大于40MHz。     

Novel planar, square-shaped, dielectric-waveguide, single-, and dual-mode filters

This paper presents a novel concept of a square-shaped dielectric-waveguide resonator, which can easily realize a dielectric-waveguide cross-coupled filter or a dielectric-waveguide dual-mode filter, using the conventional printed circuit board (PCB) process. This planar dielectric-waveguide resonator has a higher Q value than a microstrip resonator. The physical mechanisms of both single- and dual-mode filters are elucidated. Some new coupling structures are developed for undergoing the PCB process. Filter design procedures are detailed. Design curves for the coupling coefficients of internal- and external-coupling structures are determined by full-wave finite-element-method electromagnetic calculations. Measurement results are highly consistent with theory for all trial filters. This study offers an effective means of producing low-cost high-performance planar circuit filters.     

Novel Multifold Finite-Ground-Width CPW Quarter-Wavelength Filters With Attenuation Poles

This paper proposes a novel multifold finite-ground-width coplanar waveguide (CPW) lambda/4 resonator filter that has the capability of realizing attenuation poles by cross coupling of nonadjacent resonators. The newly proposed multifold structures not only greatly shrink the length of a resonator, but also provide a convenient way to implement cross coupling in a filter. The proposed multifold finite-ground-width CPW resonators can have much stronger coupling than that of spiraling and meandering layouts, and any number of folds is possible. Two combline filters are designed and measured with twofold and threefold lambda/4 finite-ground-width CPW resonators. A trisection and a quadruplet generalized Chebyshev filter formed by cross couplings between nonadjacent resonators have been implemented by modifying the layout of the resonator. These filters are smaller in size and have the capability of controlling attenuation poles     

Compact dual-mode elliptic-function bandpass filter using a singlering resonator with one coupling gap

A novel microwave dual-mode elliptic-function bandpass filter with one coupling gap structure is proposed. This filter has a 4.7% bandwidth at 1.805 GHz with 1.73 dB insertion loss. The filter provides less field perturbation of the ring resonator than conventional filters. Without the output coupling gap between the feed line and the ring resonator, a low insertion loss has been obtained. This compact, high performance filter is useful for mobile and personal communication systems     

一种新型广义交叉耦合滤波器的设计

含广义交叉耦合的N个谐振器滤波器,即含源-负载交叉耦合的滤波器能产生N个传输零点,通过给出这种滤波器的等效网络模型和传输函数,设计了两种新颖六边形结构的含源-负载交叉耦合的微带滤波器,一种为对称结构,一种为非对称结构.对其进行了仿真分析,仿真结果与理论值吻合较好.与传统两腔发夹形滤波器相比,这种两腔六边形结构的滤波器尺寸要缩小27.5%,频率选择性更高.     

Rigorous analysis of novel dielectric resonator filters with printed tuning septum

This paper describes the analysis of dielectric resonator filters with printed tuning septum in waveguide sections operating below cutoff. In this design approach a thick dielectric slab of high permittivity is placed longitudinally in the waveguide. A bilateral ladder-shaped metallization determines the resonator and coupling sections (modified finline filter). In contrast to conventional dielectric resonator filters, this approach provides better passband separation and increased stopband attenuation. Furthermore, due to the bilateral tuning septum, the resonator and coupling sections can be manufactured accurately with photolithographic techniques rather than by expensive machining.     

Generalized dual-plane multicoupled line filters

The authors describe the general realization of elliptic function narrow-bandpass filters constructed from two adjacent planes of microstrip quasi-TEM line resonators. This dual-plane configuration allows nonadjacent coupling to be realized through small slots between the planes. Alternate sign coupling is realized by the appropriate positioning of the slot along the resonator length. A model developed from H. Bethe's small-hole coupling theory (1944) is used to predict these couplings. Adjacent resonator couplings are modeled using a coupled-line analysis modified to characterize the coupling of an inhomogeneous medium. The filter synthesis technique previously developed for waveguide cavity filters can be directly applied in designing a dual-plane filter     

Design and Performance of Coplanar Waveguide Bandpass Filters

End-coupled resonator bandpass filters built in coplanar waveguide are investigated. The admittance inverter parameters of the coupling gaps between resonant sections are deduced from experiment, and bandpass filter design rules are developed. This allows easy filter synthesis from "prototype" low-pass designs. Measurements of single section resonator quality factors are used to predict filter insertion losses. Several examples of filters realized in coplanar waveguide are presented. Odd-mode coplanar waveguide filter elements that shortcircuit the even coplanar waveguide mode are investigated. Filter tuning, accomplished by adjusting the height of conducting planes above the resonant filter sections, is demonstrated.     

Microwave filters with improved spurious performance based onsandwiched conductor dielectric resonators

Microwave filters based on a novel resonator comprised of a sandwiched conductor dielectric resonator (SCDR) loaded in a cylindrical cavity are analyzed in this paper. The SCDR is a compact resonator that exhibits good spurious performance. Resonant frequencies of the lower order modes are analyzed, and mode charts, unloaded Q, slot coupling, and screw coupling graphs are presented. S-parameters are computed using the finite-difference time-domain (FDTD) method for one- and four-pole SCDR filters and compared with measured results. The measured spurious performance for the four-pole elliptic function filter shows a large improvement over conventional dielectric-resonator filters. The measured results agree closely with predicted values obtained using the FDTD method     

波导微环共振滤波器的滤波特性分析

根据波导耦合模理论详细研究了微环共振滤波器的滤波特性,分析了单环、串联双环、串联三环结构等波导微环共振滤波器的滤波特点。通过模拟计算发现,滤波带宽平坦化程度和信道串扰大小主要依赖于由波导构成的各方向耦合器之间的功率耦合比k,同时微环波导的损耗是器件滤波特性劣化的重要原因。在一定优化参数条件下,多环结构的滤波效果优于传统单环结构,并且各方向耦合器功率耦合比k值的优化取值范围扩大,降低了器件工艺实现难度。     

Design of Microstrip Dual-Mode Filters Based on Source-Load Coupling

In this letter, a novel circular open-loop resonator is presented. The field patterns of this type of dual-mode resonator are investigated using full-wave electromagnetic simulations. The applications of the dual-mode resonator as bandpass filters are proposed. A coupling and routing scheme is presented to model the operations of these filters. Advantages of using this type of filter are not only its low insertion loss, but also its controllable transmission zeros. Both simulated and measured results are presented.