双模微带三角形贴片滤波器的改进设计

双模微带谐振器用于微波滤波器设计时具有独特的优点。近年来出现了一些由双模微带三角形贴片谐振器设计的滤波器,这类滤波器结构简单,尺寸小,通带损耗小,功率容限大。但是也都存在一些共同缺陷,诸如带外抑制能力较差,容易受到高次谐波分量的干扰等等。本文在原有设计的基础上,提出了新的改进措施。实验和测量结果均表明,改进后的滤波器克服了原有的缺陷,性能得到很大改善,可以得到广泛应用,特别在高温超导(HTS)工艺中具有更加诱人的应用前景。     

采用分形贴片的一种新型带通滤波器

为了实现微波平面带通滤波器的小型化和高选择性,本文以一种分形结构贴片作为基本单元,通过一种直接抽头耦合结构,设计了单个分形贴片和多个分形贴片构成的新型微波平面带通滤波器.给出了滤波器性能的电磁仿真计算数值结果和实验结果.该类滤波器在小尺寸、低插入损耗和高选择性方面的性能明显优于传统的微带带通滤波器.     

慢波结构SIR双频带通滤波器设计

本文通过分析阶梯阻抗谐振器（SIR）和慢波结构谐振器的特性,提出了利用SIR谐振器的寄生通带产生第二通带的双频带通滤波器设计方法,以达到滤波器小型化的目的;并基于0°馈电结构获取传输零点的原理对滤波器阻带性能进行优化。最后结合ADS仿真软件设计了一个中心频率在2.4GHz和5.2GHz的微带双频带通滤波器。仿真结果表明滤波器具有良好的带内带外特性。本文所设计的滤波器尺寸小,性能好,具有很好的实用价值。     

基于折叠双模谐振器结构的微带带通滤波器

设计了一种采用折叠双模谐振器结构的新型双模微带带通滤波器。通过在折叠双模谐振器两侧加载交叉耦合结构,使通带两端产生一对传输零点。实验结果表明,该滤波器具有结构紧凑,体积小,损耗低,带外抑制性能好等优点,且其中心频率为3.65GHz,通带为2.5~4.8GHz,最大回波损耗优于-33.5dB,最小插入损耗为-0.18dB,实测结果和仿真结果相吻合。     

基于折叠双模谐振器结构的微带带通滤波器

设计了一种采用折叠双模谐振器结构的新型双模微带带通滤波器。通过在折叠双模谐振器两侧加载交叉耦合结构,使通带两端产生一对传输零点。实验结果表明,该滤波器具有结构紧凑,体积小,损耗低,带外抑制性能好等优点,且其中心频率为3.65 GHz,通带为2.5～4.8 GHz,最大回波损耗优于-33.5 dB,最小插入损耗为-0.18 dB,实测结果和仿真结果相吻合。     

一种小型化交叉耦合微带带通滤波器的设计

在现代通信技术的不断发展下,要求射频滤波器尺寸更小、性能更佳。而使用交叉耦合构造可控传输零点,则可在更少的谐振器下达成相同的性能指标。基于此,构造了1/4波长谐振的谐振器进行小型化,引入交叉耦合构造带外传输零点,并对滤波器版图合理优化布局,设计了一款小型化交叉耦合微带带通滤波器。通过HFSS建模仿真并测试了带宽在10.2～11 GHz的六阶小型化交叉耦合微带带通滤波器,测试结果表明,性能曲线与仿真曲线相吻合,成功验证了所设计结构的可行性。     

交叉耦合盒式结构微带带通滤波器设计

设计了一种交叉耦合盒式结构微带带通滤波器。采用耦合矩阵方法对交叉耦合盒式结构带通滤波器频率响应特性进行了分析,并且在此基础上研制了一种基于E型双模谐振器的非对称响应带通滤波器。滤波器中心频率为6.4 GHz,带宽为0.8 GHz,最小带内插损为1.9 dB,两个传输零点分别位于4.5 GHz 和7.6 GHz,上下阻带抑制度分别大于35dB、47dB。滤波器有效尺寸约为0.34λg *0.43λg。该滤波器具有结构紧凑、带外抑制度高、选择性高的优点。     

基于微带贴片谐振器的高选择性双模双通带带通滤波器的研究

本文提出了基于微带贴片谐振器的高选择性双模双通带带通滤波器及一种模式分析算法.首次利用该算法分析了微带贴片的模式组成,计算了导模场的闭式解.微带贴片的耦合馈线同时作为谐振单元构成第二个通带,减小了结构尺寸.全波仿真分析（full wave analysis）结果及测试数据表明,与现有的双模双通带带通滤波器相比,本文设计的滤波器传输零点个数增加了2倍,达到11个,带外抑制度达到20dB,带内插损较小,仅为1.2dB,抑制了寄生通带.同时设计的拓扑结构复杂度较低,利于滤波器的小型化.     

S波段传输零点可控的双频滤波功分器

为了更好地满足无线通信系统对微波电路双频/多频段的需求,基于微带-槽线双层结构设计了一款应用于S波段的双频滤波功分器。首先,在单个半波长微带谐振器基础上,利用枝节加载技术设计一款双模谐振器,实现双频带通滤波器设计,并将该滤波器与Wilkinson功分器进行集成,实现双频滤波功分器设计;其次,利用微带线和槽线的对偶关系,在不增加电路尺寸的基础上,引入双模槽线谐振器与微带谐振器进行垂直级联,从而展宽滤波功分器的两个通带带宽;最后利用枝节加载技术优化馈电网络。由于双模微带-槽线谐振器和馈电网络自身的特性,在每个通带的两侧分别产生一个传输零点,实现较高的带外选择性,且每个传输零点单独可控。双频滤波功分器的两个通带中心频率分别工作于2.17 GHz和3.55 GHz,相对带宽分别为8.29%(2.08～2.26 GHz)和8.15%(3.41～3.7 GHz)。仿真结果和实测结果基本吻合。     

一种新型基于交指电容和微带电感的单层低成本宽带带通滤波器

随着无线通信系统的快速发展,尤其是5G时代的来临,带通滤波器作为射频前端的选频器件被广泛应用于各种系统.近年来,人们对通信的需求日益提升,因此滤波器的小型化、低成本以及高性能等方面的要求成为业内研究的重点.现代工艺技术的发展为带通滤波器的设计提供了多种方法,如使用阶跃阻抗谐振器设计微带带通滤波器、利用互补开环谐振器作为基本谐振单元构造宽带带通滤波器和基于E型双模谐振器设计微带带通滤波器等.然而,这些微带滤波器的尺寸较大,令实现小型化的目标难以实现.由于集总元件具有体积小、成本低、带宽宽、元件间相互作用小等优点,在射频器件设计中发挥着重要作用.相较于基于集成无源器件（Integrated Passive Device,IPD）工艺和低温共烧陶瓷（Low-Temperature Co-fired Ceramic,LTCC）工艺的带通滤波器,这种单层宽带带通滤波器具有更低的生产成本、更少的损耗限制,以及避免了基于表面贴装器件的成本和制造公差等问题.由于其采用交指电容和微带电感的简单实现方式,该方法所设计的滤波器还具有工艺简单和体积小的优点.基于单层印刷电路板（Printed Circuit ...     

Theory and experiment of dual-mode microstrip triangular patch resonators and filters

In this paper, we report on the results of an investigation into dual-mode operation of microstrip triangular patch resonators and their applications for designing dual-mode bandpass filters. It has been found theoretically that the dual modes can result from the rotation and superposition of a fundamental mode. The characteristics of the dual modes and their mode splitting are described. The applications of this new type of dual-mode microstrip patch resonator in the design of microwave planar filter are presented. A circuit model for operation of this type of filter is proposed. Two- and four-pole filters of this type are demonstrated for the first time. Both theoretical and experimental 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.     

Bandpass filter design using a microstrip triangular loop resonator with dual-mode operation

A bandpass filter (BPF) design using a dual-mode microstrip triangular loop resonator is presented for the first time. The circuit produces frequency responses with one real finite frequency transmission zero and one imaginary finite frequency zero on either side of the passband. Depending on the perturbation arrangement, the nature of the coupling between degenerate modes causes the zeros to exchange their axis locations from real to imaginary and from imaginary to real while keeping their magnitude. This behavior results in frequency responses that are suitable for applications with asymmetrical requirements. Results show 8% bandwidth filters with insertion loss ranging from 0.82 dB to 1.4dB at 10 GHz. Advantages in size reduction and design flexibility are demonstrated when the triangular loop is compared to other dual-mode resonators.     

A joint field/circuit model of line-to-ring coupling structures andits application to the design of microstrip dual-mode filters and ringresonator circuits

A joint field/circuit model is proposed in this paper to characterize a class of line-to-ring coupling structures for design and optimization of microstrip dual-mode filters and ring resonator circuits. The generic model is derived from field theory and presented in terms of circuit elements by applying a newly developed numerical deembedding technique called “short-open calibration” in a deterministic method-of-moments scheme. It provides a new design strategy for characterizing and optimizing electrical performance of the line-to-ring coupling structures. Such three-port topologies are explicitly formulated by using an equivalent network having circuit elements calculated by the proposed joint field/circuit model. Three microstrip tightly coupling geometries and their related ring resonators are studied with the extracted J-inverter susceptance parameters. Experiments are performed to validate the joint model and also show coupling characteristics of the three types of line-to-ring circuit for the design of ring resonators and dual-mode filters. With this new technique, an optimized microstrip dual-mode filter is successfully designed and the prediction agrees well with our measurements     

Realisation of quasielliptic function filter using dual-modemicrostrip square loop resonators

A novel realisation of quasielliptic function narrowband bandpass filters constructed from face-to-face dual-mode microstrip square loop resonators is proposed. The new filter configuration allows crosscoupling between the degenerate modes of individual dual-mode resonators. The realisation has been confirmed both theoretically and experimentally     

T形贴片双模微带带通滤波器

基于传统的T形贴片双模微带带通滤波器,提出了一种新型的加入缝隙耦合的T形双模微带带通滤波器。在T形贴片谐振器的两侧以缝隙耦合的方式插入馈线,并对其进行了优化。优化后的滤波器能在通带两侧都产生衰减极点,提高了阻带的抑制能力,对其进行了仿真。仿真结果表明,该滤波器通带的中心频率为5.0 GHz,与实测结果基本一致,滤波器尺寸为34 mm×24 mm,保证了滤波器的小型化。     

A novel dual-mode bandpass filter with wide stopband using the properties of microstrip open-loop resonator

A novel dual-mode microstrip square loop resonator is proposed using the slow-wave and dispersion features of the microstrip slow-wave open-loop resonator. It is shown that the designed and fabricated dual-mode microstrip filter has a wide stopband including the first spurious resonance frequency. Also, it has a size reduction of about 50% 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.     

Compact size and low insertion loss Chebyshev-function bandpassfilters using dual-mode patch resonators

A compact Chebyshev-function bandpass filter using dual-mode patch resonators is proposed. The filter presents 75% size reduction compared with the conventional Chebyshev bandpass filter using two square patch resonators. Because of inset feeding and only one coupling gap being required, the new filters can achieve a low insertion loss of 1.1 dB and reduce the fabrication uncertainties     

Millimeter-Wave Ultra-Wideband Bandpass Filter Employing Dual-Mode Ring Resonators Fed by Step-Impedance Coupled Lines

This paper presents a novel millimeter-wave ultra-wideband (UWB) bandpass filter (BPF) based on microstrip dual-mode rectangular ring resonators. In order to get strong coupling between the input/output line and the dual-mode ring resonators, a step-impedance parallel-coupled structure is adopted for the design of the filter. On the other hand, transmission zeros are produced by the dual-mode resonator. As a consequence, the filter has low insertion-loss in its passband, sharp attenuation in its lower and upper stopbands and very wide stopbands. As an example, a filter with two dual-mode ring resonators is designed and fabricated. The measured frequency property of the fabricated filter shows good agreement with the simulated response.     

Novel Dual-Mode Dual-Band Filters Using Coplanar-Waveguide-Fed Ring Resonators

This paper presents a novel approach for designing dual-mode dual-band bandpass filters with independently controlled center frequencies and bandwidths. Two microstrip perturbed ring resonators are employed to obtain dual-mode dual-band responses. Novel feeding structures are introduced to simultaneously feed the ring resonators and conveniently control the coupling strength between resonators and feeding lines, resulting in a wide tunable range of external quality factors. Two kinds of filter configurations with compact size are proposed. Both of them provide sufficient degrees of freedom to satisfy various requirements of external qualify factors and coupling coefficients at both passbands. Therefore, the center frequencies and fractional bandwidths of both passbands can be independently tuned to desired specifications within a wide range. To verify the proposed method, four filters are implemented. The measured results exhibit dual-mode dual-band bandpass responses with high selectivity.