含源-负载交叉耦合的准椭圆函数滤波器设计

该文首先提出了含源-负载交叉耦合滤波器的等效网络模型,并给出了这种结构的传输函数t（s）以及矩阵的综合方法。由含源-负载交叉耦合二端口网络的短路导纳矩阵推导了耦合矩阵M中MSL、MSi和MiL的一般表达式。最后,设计了一种新颖结构的含源-负载交叉耦合的微带滤波器,对其进行了仿真与制作,实测结果与仿真值、理论值吻合较好。     

含源-负载交叉耦合的准椭圆函数滤波器设计

该文首先提出了含源-负载交叉耦合滤波器的等效网络模型,并给出了这种结构的传输函数t(s)以及矩阵的综合方法。由含源-负载交叉耦合二端口网络的短路导纳矩阵推导了耦合矩阵M中MSL、MSi和MiL的一般表达式。最后,设计了一种新颖结构的含源-负载交叉耦合的微带滤波器,对其进行了仿真与制作,实测结果与仿真值、理论值吻合较好。     

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。     

含源-负载耦合的准椭圆函数滤波器小型化优化设计

提出一种新型含源-负载耦合的交叉耦合微带带通滤波器,该滤波器的传输特性由分布在介质上下表面的开环谐振器通过引入位于两介质层中间公共地板上的开缝耦舍得到,且将位于顶层的源引入底层,实现了层间源、负载的容性耦合,确保了带外的传输零点,并对源、负载间的耦合进行了等效电路分析。与传统边缘耦合的平面结构滤波器相比,体积减小为原来的一半,且带外抑制良好。三维仿真软件HFSS用来计算该滤波器的耦合系数,并协同Ansoft公司的Designer,通过对参数的提取来迭代优化该滤波器,有效地减少了滤波器的优化时间。对滤波器进行了仿真与实测,其结果表明,实测与理论值、仿真值吻合较好。     

交叉耦合技术及LC滤波器设计分析

对滤波器交叉耦合技术进行了研究,分析了交叉耦合的矩阵理论,并大致分析了其拓扑结构.从理论上提出了交叉耦合三维拓扑模型,相对于实际应用中的二维拓扑模型,这种结构更为简单,更能充分利用各个耦合腔之间的耦合结构.把交叉耦合结构应用于LC滤波器设计中,计算与仿真结果表明,这种结构可以减少滤波器元器件数目,降低成本,提高性能.     

交叉耦合滤波器设计与传输零点的独立性分析

对具有陡峭带外特性的交叉耦合滤波器进行了分析,以四腔交叉和三腔交叉耦合形式作为单元电路,发现了相连时各节电路的带外传输零点各自独立,这一特点使得这种结构的滤波器容易调节,通过实例证明了该操作的可行性和正确性。采用发夹式微带线结构进行滤波器设计,同时运用全波电磁分析软件,对滤波器进行了仿真、优化并对其结果作了讨论分析。     

交叉耦合在直线型波导滤波器中的研究

利用相位关系和交叉耦合的模型,提出了直线型波导滤波器的一种关于交叉耦合的具体实现方法:即在不相邻的腔体之间直接用同轴线引入交叉耦合。采用这种方法设计了一种五腔滤波器,应用HFSS软件进行了仿真验证。结果表明,所设计的滤波器整体结构得到简化,中心频率为8.5 GHz,带宽为150 MHz。     

一种新颖微带双通带带通滤波器的设计方法

本文提出了一种新颖的微带双通带带通滤波器的设计方法。该微带双通带滤波器由两个中心频率不同的滤波器组成,并采用耦合线实现外部耦合。设计中引入源与负载之间的耦合,得到了额外的有限频率传输零点,改善了滤波器的衰减特性。通过调节源与负载之间耦合的强弱,可以适当地调节传输零点的位置。经设计并加工了一款4阶微带开环结构双通带滤波器,实测响应与仿真响应吻合较好,验证了该方法的有效性。     

一种新型的T型双模微带带通滤波器

提出了一种新型的T型双模微带带通滤波器结构,即在T型谐振器的两侧通过交叉耦合结构和加载开路支节,分别实现了在通带外的低阻带产生一个传输零点和高阻带产生了两个衰减极点,提高了阻带的抑制能力,同时保证了滤波器的小型化。该滤波器的仿真结果表明,通带的中心频率为3.1GHz,最大回波损耗优于-40dB,最小插入损耗为-0.1dB,实测和仿真结果相一致。     

一种小型的交叉耦合阶梯阻抗谐振器带通滤波器

利用小型化的阶梯阻抗谐振器设计了一种交叉耦合带通滤波器.引入的交叉耦合结构在带外产生了一对传输零点以更好地抑制带外干扰信号而不影响通带特性.由于采用了小型化的阶梯阻抗谐振器,交叉耦合带通滤波器尺寸大为减小,同时寄生通带移向更高端.实验和仿真结果基本一致.     

Design of hexagonal filter with source-load coupling

A method for synthesising a novel hexagonal filter with source-load coupling is presented. The equivalent circuit of the lowpass prototype of a general lossless coupled resonator filter is proposed, and the corresponding transfer function t(s) is derived. A novel quasi-elliptic function microstrip hexagonal filter is designed and fabricated. Simulated and measured results are presented. Compared with the conventional cross-coupling filter, the proposed hexagonal filter acquires more than 27.5% size reduction and provides improved selectivity by a relatively small bandwidth     

Design flexibility of an open-loop resonator filter using similarity transformation of coupling matrix

In this letter, the design flexibility of an elliptic-response open-loop resonator filter is achieved through similarity transformation of the coupling matrix. To verify the proposed method, a compact four-pole elliptic-response bandpass filter is designed using the conventional structure with open-loop resonators. Designed filter has the resonators with very narrow spacing for the required coupling coefficient and it is impossible to implement a filter with wider fractional bandwidth. Two possible configurations to overcome this problem are presented through similarity transformation of the coupling matrix. From this design flexibility, a filter with wider fractional bandwidth is designed with realizable design parameters.     

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     

A compact open-loop resonator filter with a wide stopband response

This paper presents a new class of microstrip slow-wave open-loop resonator filter with reduced size and improved stopband characteristics. A comprehensive treatment of both resonator ends loaded with triangular and rectangular shapes is described, leading to the invention of a microstrip slow-wave open-loop resonator. A four-resonator bandpass filter is designed at the operating frequency about 2 GHz, bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The proposed filter is not only compact size due to the slow-wave effect but also has a wider upper stopband resulting from the dispersion effect. The filter design of this type will be described in detail. The experimental results are demonstrated and discussed.     

Design of Dual-Band Bandpass Filters Using Stub-Loaded Open-Loop Resonators

In this paper, open-loop resonators loaded by shunt open stubs are proposed to design compact dual-band bandpass filters with improved out-of-band rejection characteristics. The second passband of the dual-band filter is obtained by tuning higher resonant modes of the open-loop resonator by the stub length and position. A tapped-line input/output feed structure is used for external coupling. Required external coupling is obtained by adjusting the tapping position and dimension of the stub-loaded resonator. A lossless transmission line model is used to determine the resonance properties of the resonator and the external quality factor. Theoretical predictions are verified by the experimental results of three dual-band filters.     

LTCC宽边耦合交指型超宽带滤波器设计

提出用交指型结构实现超宽带（UWB）带通滤波器的小型化,并给出了设计方法。该结构通过宽边耦合实现超宽带滤波器需要的较大耦合系数,并通过加宽带状线谐振器的宽度减少不必要的交叉耦合,简化了滤波器的设计。最终设计了一个中心频率为f0,相对带宽为58%的六阶交指带通滤波器,滤波器尺寸仅为8 mm×11 mm。从仿真结果看,该滤波器保持了传统交指型滤波器阻带特性好,寄生通带远的优点。     

基于枝节加载开环谐振器的带阻滤波器设计

提出了一种具有良好谐波抑制功能的双枝节加载开环谐振器,加载枝节采用均匀阻抗结构,与同尺寸的开环谐振器相比,结构更紧凑,能够更好地抑制寄生模,而且可以达到更低的谐振频率。分析了加载枝节参数对带阻滤波器抑制二次谐波的影响。通过在加载的双枝节间引入集总可变电容,可以使谐振器具备谐波抑制性能的同时,实现中心频率可调的功能。基于双枝节加载环谐振器设计出一种可调带阻滤波器,中心频率可以在900MHz ~2. 65GHz 范围内调节,而且最低寄生阻带能够抑制到8GHz。     

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.     

A reduced-size dual-mode bandpass filter with capacitively loaded open-loop arms

A novel type of dual-mode microstrip bandpass filter using degenerate modes of a dual-mode microstrip square loop resonator with capacitively loaded open-loop arms is proposed. Such a dual-mode bandpass filter with a 0.75% bandwidth at the center frequency of 1.603 GHz is designed and fabricated to demonstrate the design of reduced-size microstrip filters. It is shown that the proposed filter has a size reduction of about 59% at the same center frequency, as compared with the dual-mode bandpass filters such as microstrip patch, cross-slotted patch, square loop and ring resonator filter.