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.     

多带外传输零点微带带通滤波器设计

设计了一种梳状微带平行耦合线窄带带通滤波器,仅应用两腔结构就实现了带外5个传输零点.通过微带线开路枝节,平行耦合线结构,以及馈电位置和两个梳状线谐振器之间的耦合,在通带附近引入了3个传输零点;四分之一波长平行耦合线接地短路结构,在带外高频产生额外两个传输零点,进而可有效抑制零点频率附近的杂波干扰.实测结果表明,设计的滤...     

基于枝节加载谐振器的新型三频带通滤波器设计

提出了一种新型平面三频带通滤波器,该滤波器由一个加载短路枝节的阶梯阻抗谐振器,一对加载开路枝节的背靠背E型谐振器,以及包含源负载直接耦合的馈电结构组成.所采用的枝节加载谐振器的多模工作特性使滤波器的体积大大减小,同时每个通带的位置及其耦合特性都能够独立调谐.另外,通过源负载直接耦合引入通带两侧的传输零点,实现了滤波器良好的频率选择性.最后设计并加工了一款高选择性小型化三频带通滤波器,其三个通带的中心频率分别为2.0GHz,3.95GHz和6.35GHz,插入损耗均小于2.5dB,带内回波损耗均优于14dB,实验结果与仿真结果吻合良好.     

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.     

COMPACT COUPLED LINEAR TAPERED LINE BANDPASS FILTER WITH TWO TRANSMISSION ZEROS

A new compact bandpass filter composed of two coupled linear tapered line resonators (LTLRs) is designed. The two resonators are arranged in different layers. The filter has two transmission zeros on both sides of the passband. It has small size and steep response below its passband. It is also shown that this filter has 0.6 dB low insertion loss at the centre frequency and 10.5% 3dB bandwidth.     

一种新型传输零点可控的微带带通滤波器

提出了一种新型的传输零点可控的微带带通滤波器结构,它由一段低阻抗线和与之相连的平行耦合线构成。通过调节低阻抗线与平行耦合线的偶模阻抗比,可以改变谐振器的2个模式之间的距离,从而灵活的调节滤波器的带宽;而通过调节平行耦合线的间距,则可以方便的调节传输零点的位置。仿真与实测结果都表明该滤波器具有良好的性能：低插损,结构紧凑,可以灵活的调节带宽和传输零点的位置。     

Pseudo-elliptic microstrip line filters with zero-shifting properties

The paper presents a new design of pseudo-elliptic microstrip line filters. These filters employ a coupling scheme which allows shifting of transmission zeros from one side of the passband to the other by only changing the resonant frequencies of the resonators. To demonstrate the performance of these filters, a fourth-order bandpass filter with one transmission zero in the upper stopband is first designed. A second filter with a transmission zero in the lower stopband is then designed by simply adjusting the lengths of the resonators followed by minor optimization to account for the fact that the resonant frequencies can not be changed without slightly affecting the coupling coefficients in the used layout. Measured and simulated results are presented.     

A Compact Wideband Bandpass Filter Using Transversal Resonator and Asymmetrical Interdigital Coupled Lines

A compact wideband microstrip bandpass filter using transversal resonator and asymmetrical interdigital coupled lines is proposed in this letter. A wide passband is first constructed using transversal signal-interference technique, resulting a pair of transmission zeros at each side of the desired passband. By driving this transversal resonator with two asymmetrical interdigital coupled lines at two sides, five extra transmission zeros are generated in the lower/upper stopbands with excellent dc-choked property, thus making up a wide passband with improved out-of-band performance. This wideband microstrip filter is then designed, implemented and experimented. Good insertion/return losses, flat group delay and good out-of-band rejections are achieved as demonstrated in both simulation and experiment.     

Performance improvement and size reduction of microstrip dual-mode bandpass filter

A novel miniaturised dual-mode bandpass filter with multi-arc resonators is proposed. The size of the dual-mode filter can be reduced significantly by using the microstrip dual-mode resonator consisting of multi-arcs; meanwhile insertion loss and spurious response suppression are improved A prototype filter is designed and implemented at 3.6 GHz with 2.8% fractional bandwidth, which shows a low passband insertion loss of 1.02 dB and a wide stopband with rejection better than 20 dB up to about 8.5 GHz.     

Asymmetrically-loaded interdigital coupled line for wideband microstrip bandpass filters with good out-of-band performance

An asymmetrically-loaded interdigital coupled line is proposed for design of wideband microstrip bandpass filters with good out-of- band performance. This interdigital coupled line with three fingers is formed by stretching one of two outer arms with one two-stage open-ended stub. Its characteristics are analysed in terms of admittance matrix to exhibit simultaneous emergence of extra transmission zeros in lower and upper stopbands. A wideband filter with two half-wavelength resonators is then designed and fabricated. Measured results show low-loss wide passband in the range 2.95-5.15 GHz and highly attenuated stopbands at DC to 2.2 GHz and 6.6-10.0 GHz, respectively.     

高选择性发夹型带通滤波器的设计

微带发夹型带通滤波器具有尺寸小、结构简单、性能稳定等优点,在射频微波领域有着广泛的应用。 本文使用ADS 软件设计仿真了一种高选择性抽头式发夹型带通滤波器。与一般发夹型滤波器相比,该滤波器在输 入输出端并联四分之一波长开路微带线,通过在寄生通带增加传输零点的方法提高滤波器的带外抑制性能。另外, 在该滤波器的谐振单元上增加并联阶跃阻抗枝节,在通带两侧产生一对传输零点,来提高该发夹型带通滤波器的选 择性。最后对这种高选择性发夹型带通滤波器进行实物加工,测试结果证实了该带通滤波器的良好选择性能。     

Compact Ultra-Wideband Microstrip/Coplanar Waveguide Bandpass Filter

A novel ultra wideband (UWB) bandpass filter is presented, using a compact coupled microstrip/coplanar waveguide (CPW) structure. The filter comprises of a single CPW quarter-wavelength resonator which is coupled to two microstrip open-circuited stubs on the other side of a common substrate. The two microstrip open-circuited stubs, which are about a quarter-wavelength long at the center frequency, can function as two resonators with associated coupling arrangement to the CPW. This forms a very compact three-pole filter. The proposed filter also exhibits a quasi-elliptic function response, with one finite-frequency transmission zero closer to each side of the passband. Thus, a high selectivity is achieved using a small number of resonators, which leads to low insertion loss and group delay across the passband. The performance is predicated using EM simulations and verified experimentally. The experimental filter shows a fractional bandwidth of 90% at a center frequency of 6.4GHz, with two observable transmission zeros (attenuation poles) at 1.95 and 10.36GHz, respectively. Furthermore, it has a very small size only amounting to 0.25 by 0.08 guided wavelength at the center frequency     

基于双模谐振器的W波段波导带通滤波器

带通滤波器为现代毫米波系统中进行频率选择的重要器件,而波导滤波器因其低损耗、大功率容量、易加工等优点成为首选。为满足系统的小型化要求,设计了一种基于双模谐振器且具有准椭圆函数响应的W波段波导带通滤波器。该波导带通滤波器结构简单紧凑,由两个双模方形脊谐振腔组成,可获得2 个传输零点及四阶准椭圆函数响应。滤波器样品选取紫铜材质,采用CNC 技术加工制作。经矢量网络分析仪测试,该滤波器通带内插损低,达0.5 dB,3 dB 波束带宽为4.35 %(92.2 ~96.3 GHz),回波损耗优于20 dB,通带外存在两个非对称零点。在全W波段的测试结果与仿真数据高度吻合。     

双模方形带通滤波器的分析、建模及设计

本文报道一种利用谐振器中缺口位置设计双模带通滤波器的新方法.用这种方法既可以实现具有一对传输零点的双模带通滤波器,也可以实现无传输零点的双模带通滤波器.通过分析缺口位置对谐振器内电场模式分布的影响,建立了双模滤波器的拓扑结构图.利用全波仿真软件,基于不同的缺口位置设计了中心频率为2.05GHz,带宽为100MHz的两种...     

New compact wideband bandpass filter using three parallel-coupledlines

A new miniature bandpass filter, comprising three-conductor short-circuited spurline resonators of approximately a quarter-wavelength long, with a very wide bandwidth approaching multioctaves is reported for the first time. The chain matrix of the filter resonator is derived. The new filter has been developed using microstrip line with less than 1 dB insertion loss over a passband from 2 to 8 GHz. Reasonably good agreement between the measured and calculated results is observed     

一种小型化带通滤波微带巴伦设计

提出一种小型化带通滤波微带巴伦的设计。在Marchand巴伦的基础上,使用一个半波长和两个1/4波长传输线作为谐振器,在带通滤波微带巴伦的两个输出端口可以获得相同幅度和相反相位的平衡信号。利用谐振器平行线耦合可以观察到通带两侧存在两个传输零点。对提出的中心工作频率在2.65 GHz的带通滤波微带巴伦进行了实物加工与测试。两个输出端口信号幅度差与相位差分别为±0.4 dB和180°±5°。仿真与测量结果有较好的一致性,验证了本文所提方案的可行性。     

一种具有传输零点的Hairpin带通滤波器设计

本文通过在微带（hairpin）滤波器的谐振器上并联微带开路线，构成了一种新的hairpin带通滤波器。该滤波器在通带附近有一对传输零点，具有良好的频率响应以及频率选择特性。由于这种类型的微带滤波器实现传输零点不需要通过滤波器非相邻谐振器间的交叉耦合来获得，因此，设计过程非常简单。     

374~747 MHz数字可调谐微带滤波器

通过在微带开口谐振环加载数字可调电容,设计了一种新颖数字微带可调滤波器,同时提出了新型的非均匀开口谐振环混合耦合结构,使谐振器间耦合系数随谐振频率的降低而增大,实现恒定绝对带宽可调滤波器。接着对所提出的基于5 bit数字可调电容的数字可调微带滤波器进行了仿真和制作,测试表明,其通带中心频率可实现374~747 MHz可调,?3 dB绝对带宽在44~67 MHz之间变化,OIP3大于50 dBm。     

Compact Planar Quasi-Elliptic Function Filter With Inline Stepped-Impedance Resonators

Compact microstrip bandpass filters of orders N = 4,6, and 8 with quasi-elliptic function responses are synthesized with inline stepped-impedance resonators. The filters have enhanced transition responses since two transmission zeros are generated on both sides of the passband. Existence of these two zeros is investigated by formulating the Y-matrix of the equivalent circuit for the filter and taking adjacent and nonadjacent coupling into account. Some matrix elements Y_j,j+2 representing coupling between two nonadjacent resonators are shown to have the opposite signs in both the lower and upper sides of the center frequency. This property leads to creation of the two transmission zeros on both sides of the passband. It is demonstrated that one more zero can be created in the rejection band by the tapped-line input/output scheme. Experimental circuits on substrates with epsiv_r = 2.2 and 10.2 are measured to validate the theory and design.     

Novel compact parallel-coupled microstrip bandpass filters with lumped-element K-inverters

Novel compact parallel-coupled microstrip bandpass filters are proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (/spl lambda//4) resonator filters. As a result, the filter order can be doubled without increasing the circuit area, and no repeated passband is observed at twice the center frequency. In addition, by introducing the cross-coupling effect, two transmission zeros at upper and lower stopbands may be created. Simple equivalent-circuit models are also established as effective design tools. Specifically, several compact fourth-order microstrip bandpass filters with good stopband rejection are implemented and carefully examined.