耦合窗结构窄带LTCC滤波器设计

对各种类型的阶梯阻抗谐振器进行了分析和比较,λg/2型SIR谐振器最适合LTCC滤波器的设计;同时分析了耦合窗结构原理,多层LTCC滤波器适合采用这种耦合结构,可以大大缩小滤波器的体积;本文详细介绍通过多层孔径弱耦合、小型化发夹谐振器结构的LTCC多层窄带耦合窗滤波器设计方法,并进行该结构两种滤波器实物版图加工,实测结果与仿真结果比较吻合。该结构窄带滤波器结构小巧新颖,易于集成在小型化微波多芯片组件中使用。     

Slow-wave bandpass filters using ring or stepped-impedance hairpinresonators

This paper proposes a new class of slow-wave bandpass filters that uses a microstrip line periodically loaded with microstrip ring or stepped-impedance hairpin resonators. The new slow-wave periodic structures utilize the parallel and series resonance characteristics of the resonators to construct a bandpass filter. Unlike conventional slow-wave filters, the proposed bandpass filters are designed to produce a narrow passband at the fundamental mode of the resonators. The new filters provide lower insertion loss than that of parallel- or cross-coupled ring and stepped-impedance hairpin bandpass filters. The calculated frequency responses of the filters agree well with experiments     

微带发夹型谐振器滤波器的实验研究

微带发夹型谐振器滤波器具有尺寸小、成本低、易于集成等优点,在微波平面电路的设计中有着良好的应用前景.此前已有一些文献对这类滤波器进行过研究,但一般都是只针对某一种特定的发夹型谐振器进行滤波器的分析设计,而没有对各种不同谐振器的性能指标与滤波器设计要求进行比较研究.本文使用几种不同的发夹型谐振器和不同耦合方式分别设计了三阶和四阶带通滤波器,通过实验对这几种谐振器滤波器进行了分析研究,得到了一些具有实际应用价值的结论.     

Microstrip Tapped-Line Filter Design

The subject of this article is a step-by-step design procedure for microstrip tapped-line filters, accompanied by appropriate design curves. In addition to microstrip tapped-line interdigital filters, a new hairpin-line filter using tapping is introduced. The equation to equation the singly loaded Q for hairpin resonators produced by tapping is derived. Experimental data is presented for filters over 20-percent bandwidth.     

Miniaturized hairpin resonator filters and their application toreceiver front-end MICs

The authors describe the fundamental characteristics of miniaturized hairpin resonators having parallel coupled lines and show their applications to bandpass filters and receiver front-end microwave integrated circuits (MICs). A method for calculating filter coupling parameters using a general-purpose microwave circuit simulator is presented. The bandpass filters have a suitable structure for MICs, and their size is one-half that of conventional hairpin resonators without increasing insertion losses. Trial receiver front-end MICs using these filters have been developed and have shown good characteristics such as low noise and a high image suppression ratio. They are applicable to a frequency range above the L-band     

RF-MEMS谐振器和滤波器研究进展

介绍了基于梳状、梁式、圆盘三种结构的射频微机电系统( RF-MEMS)谐振器及滤波器,并对RF-MEMS谐振器及滤波器的结构与性能参数进行讨论;分析RF-MEMS谐振器及滤波器设计和制造中的有关问题及其处理方法;RF-MEMS谐振器及滤波器性能优异,能与其他器件实现片上集成,且与集成电路工艺兼容,在射频无线通信系统中的...     

Design of Artificial Lumped-Element Coplanar Waveguide Filters With Controllable Dual-Passband Responses

This study develops an analytical design methodology for synthesizing dual-passband filters with controllable frequency responses. The novel dual-passband filters are constructed from the artificial lumped-element coplanar waveguide stub whose behavior is equivalent to that of a parallel connection of series LC and shunt LC resonators. To improve the frequency response within two passbands, the impedance matching and the phase and impedance compensations are employed in filter design by attaching additional inductors and capacitors to dual-passband resonators. Two types of filters with significantly different bandwidth and separation of two passbands are implemented and the measured results are very consistent with the theoretical predictions, sufficiently validating the proposed design methodology and filter configuration. The proposed filters realized by artificial lumped-element resonators provide the advantages over conventional dual-passband filters in terms of compact size, spurious dc passband elimination, and deep suppression between two passbands.      

A new compact microstrip two-layer bandpass filter using aperture-coupled SIR-hairpin resonators with transmission zeros

A new design of a compact two-layer bandpass filter using aperture-coupled microstrip stepped-impedance hairpin resonators is proposed and investigated in this paper. The proposed filter is composed of four stepped-impedance hairpin resonators located on two stacked microstrip layers, and the couplings between the resonators on the upper layer and those on the lower one are obtained by using three coupling apertures etched on a common ground plane placed between the two layers. In addition, the use of tapped input/output couplings allow this bandpass filter to generate two independent transmission zeros. A full-wave simulator is used to design the proposed structure and calculate the aperture coupling coefficients. With this two-layer configuration, the proposed filter becomes very compact and occupies a small space. To demonstrate the proposed design, a four-order bandpass-filter prototype was designed, fabricated, and tested at 2.14 GHz. Furthermore, a single-layer filter prototype was also designed and fabricated at the same frequency band and then compared to the first one. As a result, a significant reduction of approximately 50% was achieved. These features make the proposed structure suitable for compact and high-performance circuit component designs in microwave circuits.     

源与负载感性交叉耦合的小型介质滤波器

为了提高滤波器的阻带衰减,研究了源与负载感性交叉耦合的小型介质滤波器。首次提出一种新概念：将源和负载看作准谐振器。以贴片电感作为源与负载之间、源与第二个谐振器之间的交叉耦合元件,两个准谐振器和两个介质谐振器可构成级联四节(CQ),一个准谐振器和两个介质谐振器可构成级联三节(CT)。分析了传输零点的位置,详细讨论了这种滤波器结构的设计方法。采用介电常数为80的介质陶瓷组装了3个两级介质滤波器,并进行测试,结果表明传输零点的个数和位置与仿真设计相符合。滤波器的体积小,均为14 mm×6.5 mm×10 mm。     

Compact Millimeter-wave filters using distributed capacitively loaded CPW resonators

In this paper, a method for reducing the size of coplanar-waveguide (CPW) resonators, used in the design of compact bandpass filters, is presented. This is accomplished by incorporating a distributed array of capacitive loads along a resonant CPW line. Design of a miniaturized bandpass filter using capacitively loaded CPW resonators, which are inductively coupled, is presented. Inductively coupled bandpass filters with the proposed capacitively loaded CPW line resonators are designed and a size reduction of 25%, compared with filters using a standard CPW line resonator, is demonstrated. It is shown that, through this size reduction, the insertion loss is minimally increased (<0.4 dB). A hybrid algorithm, combining the method of moments (MOM) and circuit simulation is used to facilitate design process. Few filters using this technique are designed, fabricated, and measured at W-band. An excellent agreement between the simulation and measurement responses of these filters is presented.     

小型化三维发夹型LTCC宽带带通滤波器

利用低温共烧陶瓷(LTCC)工艺,通过通孔互联实现了三维结构的发夹型宽带带通滤波器。该结构将谐振单元的横向尺寸转移到z轴方向实现,有效减小了滤波器的尺寸并且谐振器间的耦合系数为传统结构的1.6倍。利用五个谐振器结构实现较宽的频带(>30%)和较好的选择特性。设计并实际制作了中心频率10 GHz的LTCC带通滤波器,3 dB带宽为8.8～12.1 GHz,实测指标与设计仿真结果较为吻合。     

Cross-coupled microstrip hairpin-resonator filters

A new class of cross-coupled planar microwave filters using microstrip hairpin resonators is introduced. The realization of bath the canonical and the cascaded quadruplet (CQ) filters is feasible. Coupling characteristics of four basic coupling structures encountered in this class of filters are investigated in the light of full-wave electromagnetic (EM) simulations. A four-pole cross-coupled filter of this type is designed and fabricated. Both the theoretical and experimental performance is presented     

High-Q HF microelectromechanical filters

IC-compatible microelectromechanical intermediate frequency filters using integrated resonators with Q's in the thousands to achieve filter Q's in the hundreds have been demonstrated using a polysilicon surface micromachining technology. These filters are composed of two clamped-clamped beam micromechanical resonators coupled by a soft flexural-mode mechanical spring. The center frequency of a given filter is determined by the resonance frequency of the constituent resonators, while the bandwidth is determined by the coupling spring dimensions and its location between the resonators. Quarter-wavelength coupling is required on this microscale to alleviate mass loading effects caused by similar resonator and coupler dimensions. Despite constraints arising from quarter-wavelength design, a range of percent bandwidths is still attainable by taking advantage of low-velocity spring attachment locations. A complete design procedure is presented in which electromechanical analogies are used to model the mechanical device via equivalent electrical circuits. Filter center frequencies around 8 MHz with Q's from 40 to 450 (i.e., percent bandwidths from 0.23 to 2.5%), associated insertion losses less than 2 dB, and spurious-free dynamic ranges around 78 dB are demonstrated using low-velocity designs with input and output termination resistances of the order of 12 kΩ     

Serially-connected series-stub resonators for narrowband coplanar-stripline bandpass filters

In this letter, a coplanar stripline (CPS) series resonator composed of serially-connected series-stubs is proposed. This kind of resonator provides two transmission zeros close to the resonant frequency. With the proposed structure, the reactance slope parameters of the resonators are significantly increased and adjustable by changing the length ratio of the two series stubs. This is useful for designing narrowband filters which is difficult to realize with conventional series CPS resonators. The structures of the resonators are optimized for a lower radiation loss and used to design a narrowband Chebyshev bandpass filter. The simulation and experimental results show that the proposed filter provides multiple transmission zeros and high selectivity.     

两种小型谐振器在微带均衡器中的应用

本文阐述了新型发卡式谐振器和矩形螺旋形谐振器及其在微带均衡器中的应用,利用上述两种谐振器分别设计了两种微带均衡器单子结构电路,通过仿真发现采用新型发卡式谐振器的均衡器单子结构电路具有频率调谐功能;而采用螺旋形谐振器的均衡器单子结构电路不仅具有频率调谐功能,而且具有衰减幅度调节功能,解决了由于实际加工误差引起的频率和衰减偏移问题。最后根据实际需要采用这种螺旋形谐振器设计了一个微带均衡器并给出了其频率曲线。     

A New Coupling Matrix Extracting Method From the Frequency Response

Coupled resonators are widely used in many applications, especially for filters. It is necessary to know the coupling matrix of those resonators in order to further modify and/or optimize the existing design. In recent years, many efforts have been made to generate a coupling matrix. In this paper, a new method is proposed, which can be applied for both the synchronous and asynchronous coupled resonators. With this method, the eigenvalues and eigenvectors of the coupling matrix can be generated directly from the simulated frequency responses, and the coupling matrix can then be determined. Typical examples are illustrated for the cases such as a quadruplet with an image, real, or complex transmission zeros. The impact of loss is also discussed. As a matter of fact, this method has been successfully used in the design of high-temperature superconducting filters     

Analysis of the coupling coefficients of stripline resonators in the designs of suspended-substrate filters

Expressions for the frequency-dependent coupling coefficients of stripline resonators in miniature designs of suspended-substrate filters are obtained. The effect of the design parameters of such filters on the coupling coefficients of their resonators is theoretically studied and frequency-selective properties of the device are analyzed. It is shown that interaction between resonators at frequencies of the filter passband is predominantly inductive in the presence of small capacitive interaction and the attenuation poles of the amplitude-frequency response (AFR) observed beyond the passband are caused by the mutual cancellation of inductive and capacitive interactions. Frequency dependences of coupling coefficients can be used to explain features of the AFRs of suspended-substrate filters. It is shown that experimental AFRs agree well with theoretical AFRs calculated in quasi-static approximation with the use of 1D models.     

Direct coupling between two dielectric resonators

The letter deals with a new method of calculation of direct coupling between two dielectric resonators. This method could be used for the design of microwave integrated filters. Comparison between calculated and measured values of this coupling shows good agreement.     

A universal building block for advanced modular design of microwave filters

A universal building block for modular design of microwave filters is introduced. The second order block contains two resonators which are not coupled to each other. By adjusting the strengths and signs of its coupling coefficients, the block can be used to design bandpass, bandstop and linear-phase filters. For bandpass filters, Chebychev as well as symmetric and asymmetric pseudo-elliptic responses with one or two finite transmission zeros can be designed. For linear-phase filters, two finite transmission zeros can placed practically anywhere in the complex plane as long as the realizability condition is met. Bandstop filters with no finite reflection zeros as well as symmetric and asymmetric pseudo-elliptic responses with one or two finite reflection zeros can be achieved by the same building block. The block is so flexible it can even generate bandstop responses with complex finite reflection zeros for group delay control. Higher order filters are designed modularly by cascading the appropriate number of building blocks. Coupling matrices of a number of cases are presented to demonstrate the flexibility and the universality of the building block.     

High-Selectivity single- and dual-resonator microstrip filters

New selective properties are revealed of the base section of conventional microstrip filters with circuits based on a four-wire system of coupled quarter-wave lines with one half-wave hairpin resonator. The conditions under which this single-resonator section acquires the characteristics of multi-resonator circuits due to the possibility of formation of four zeros and six operating attenuation poles at the end frequencies are determined. The structure does not contain elements short-circuited to the screen, which determines its high manufacturability. It is demonstrated that high-selectivity compact microstrip filters can be designed on the basis of single- and dual-resonator structures, i.e., the structures with the minimum number of resonators.