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。     

一种新型微带Hairpin带通滤波器的设计

通过在Hairp in滤波器的非相邻谐振间并联一段长度为λ0/2奇数倍的微带线使得在滤波器的通带两侧产生一对传输零点,构成一种新的微带Hairp in带通滤波器。该类滤波器的设计避免了交叉耦合带通滤波器求解耦合系数的复杂过程。最后给出了该类型滤波器的设计实例,仿真、测试结果证实了设计方法的正确性。     

多传输零点的宽带带阻滤波器设计

提出了一种基于横向型信号干扰的新型多传输零点的宽带带阻滤波器。通过采用终端加载一段四分之一波长开路传输线枝节的弯折型反耦合线与两段对称的半波长传输线开路枝节相并联的方式,在滤波器的阻带内引入了五个传输零点,并在通带内产生了四个反射零点,从而获得了陡峭的过渡带特性、宽阻带特性以及较好的阻带抑制水平。最终设计的宽带带阻滤波器中心频率为3 GHz,20 d B衰减带宽可达106%。     

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。     

双传输零点LTCC带通滤波器的设计与制作

采用仿真软件Ansoft HFSS,构建了具有双传输零点的LTCC带通滤波器(BPF)的物理模型,即在无传输零点的二阶带通滤波器的基础上并联一个反馈电容来实现双传输零点。根据仿真结果,采用LTCC工艺制作了封装尺寸为1206,具有两个传输零点的片式BPF样品,用矢量网络分析仪Agilent 8722ES进行测试。结果表明:测量结果与仿真数据基本相符,滤波器中心频率为2.7GHz。该滤波器适用于日益小型化的移动通信设备。     

新型传输零点可控的共面波导带通滤波器

提出了一种新型传输零点可控的共面波导(CPW)结构双模带通滤波器.该滤波器采用了新型的"王"字形共面波导谐振腔."王"字形共面波导谐振腔是由一段均匀阻抗线和两侧与之相连的"T"形枝节构成.调节谐振腔上下"T"形枝节的长度,可以改变谐振器的两个谐振模式之间的距离,从而灵活的调节了滤波器的带宽.调节"T"形枝节的长度还可以控制滤波器传输零点的位置,从而增强带外抑制.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,易于加工制作,可以灵活的调节带宽和传输零点的位置.     

交叉耦合微带带通滤波器

针对无线通信系统小型化的要求,设计了一种带有交叉耦合的带通滤波器,该滤波器采用带过孔的终端短路式耦合线为谐振单元,同时加入了交叉耦合线改善滤波特性;整个结构紧凑,具有插入损耗低、选择性高、带外抑制度佳等特点,实测结果与仿真吻合较好,中心频率为4.2 GHz,3 d B带宽为400 MHz,驻波比小于1.5,体积仅为8 mm×6 mm×0.7 mm。     

宽阻带小型化双频带通滤波器

文中提出了一种具有宽阻带的紧凑型双频带通滤波器,它采用了折叠短路枝节负载谐振器、紧凑型微 带单元谐振器(CMRC)和阶跃阻抗谐振器结构。由于多个谐振器产生了五个可控传输零点(TZ),该滤波器实现了两个 通带之间的良好隔离度以及宽阻带特性。制作并测试了尺寸紧凑的双频带通滤波器实验样品,测试结果显示,第一通 带和第二通带的中心频率/ 插入损耗分别为0. 66 GHz/0. 8 dB 和1. 73 GHz/0. 7 dB,阻带频率高达10. 5 GHz,抑制水平 超过15 dB。     

基于反耦合线的宽带带通滤波器设计

提出一种新型的基于反耦合线结构的宽带带通滤波器,该滤波器结构由一段弯折型反耦合线以及一个开路传输线枝节组成。采用奇偶模分析法对所提出的滤波器结构进行分析并进行仿真。结果表明,选择适当电路参数,该滤波器可以产生六个传输零点。对设计的两个带通滤波器(Filter-A 和 Filter-B)进行仿真和实测。结果如下：中心频率为 3 GHz 时,Filter-A 百分比带宽为 47%,Filter-B 为 40%,结果表明在带内插损较低、群延迟较好的情况下,该类滤波器在百分比带宽上有一定优势。     

Compact microstrip bandpass filter with two transmission zeros

A novel compact microstrip bandpass filter is proposed using a half-wavelength (/spl lambda//2) microstrip line resonator and an end-coupling resonator. The filter has two transmission zeros at both low and high rejection bands, as well as low insertion loss and compact design by giving two paths to the input signals. A demonstration filter has been designed and tested. Theoretical and experimental results are presented.     

Sharp-rejection microstrip bandpass filters with multiple transmission zeros

A simple design of a sharp-rejection microstrip bandpass (BPF) filter is presented. By creating multiple transmission zeros in the lower and upper stopbands, sharp rejection characteristics are obtained. The basic filter unit consists of a single parallel coupled-line section and an open-ended stub. A lossless transmission line model approach is used to derive the design equations for frequency responses and transmission zero positions. The bandwidths are controllable by the zero locations that in turn are controlled by varying the impedances of the configuration. To validate theoretical predictions, two prototype BPFs operating at lower band 2.4 GHz of WLAN are fabricated in microstrip form.     

Compact microstrip coupled-line bandpass filter with four transmission zeros

A compact coupled-line bandpass filter with multiple capacitive cross-couplings to create four transmission zeros is proposed. The locations of transmission zeros can be adjusted by varying the values of cross-coupled capacitances so as to improve the filter selectivity. The proposed filter is based on one-eighth-wavelength (/spl lambda//8) coupled-line sections and quarter-wavelength (/spl lambda//4) resonators, thus it occupies only half of the circuit area comparing with the conventional coupled-line bandpass filters. Specifically, a fourth-order microstrip coupled-line bandpass filter centered at 2.46GHz with a 3-dB bandwidth of 10.2% and four transmission zeros is implemented and examined.     

Compact microstrip bandpass filter with two transmission zeros using a stub-tapped half-wavelength line resonator

A compact microstrip bandpass filter is developed using a half-wavelength (/spl lambda//2) transmission line resonator with a pair of tap-connected open-ended stubs. Such paired stubs with total length of about /spl lambda//2 constructs an equivalent line resonator. Together with two separated /spl lambda//4 line resonators, the three transmission poles can be achieved inside the passband. Meanwhile, two stub lengths are adjusted slightly longer and shorter than /spl lambda//4 to realize the two transmission zeros at both low and high rejection bands. Further, the long tapped-stub is kept wider than its short counterpart to improve the low rejection behavior. A filter sample is designed and fabricated to provide an experimental verification on the proposed filter.     

Transversal wideband bandpass filter with a wide stopband and multiple transmission zeros

Herein, we present a compact transversal bandpass filter (BPF) with an extremely wide upper stopband and multiple transmission zeros (TZ). Three signal transmission paths with shorted stubs and open-coupled lines allow signal transmission from input port to output port. Two resonant modes can be excited simultaneously and managed easily for bandpass response. Eleven TZs are achieved via transmission path cancelation; an extremely wide upper stopband with an attenuation level better than –12 dB is achieved up to 11.7 f₀, where f₀ is the center frequency (CF). In addition, bandwidth and CF can be controlled by adjusting electrical lengths. For proof of concept, a wideband BPF centered at 1.04 GHz with 3 dB fractional bandwidths of 49.2% was designed, fabricated, and evaluated. The overall circuit measures 0.045λ_g × 0.117λ_g; good agreement was observed between the measured and simulated results.     

Compact tri‐wideband bandpass filter with multiple transmission zeros

This paper presents a tri‐wideband bandpass filter (TWB‐BPF) with compact size, high band‐to‐band isolation, and multiple transmission zeros (TZs). The proposed TWB‐BPF is based on a multiple‐mode resonator (MMR), which is interpreted by the method of the even‐ and odd‐mode analysis technique. The MMR can excite 11 resonant modes, where the first two modes comprise the first passband, the next four modes form the second passband, and the last five modes are used to generate the third passband. In addition, 10 TZs are yielded to obtain high band‐to‐band isolation and wide stopband suppression characteristics up to 14.95f_c1 (f_c1 is the center frequency of the first passband). To verify the proposed filter, a TWB‐BPF with 3‐dB fractional bandwidths (FBWs) of 37.4%, 43.5%, and 40.4% is designed, fabricated, and measured.     

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.     

具有多传输零点的微波陶瓷滤波器设计

低温共烧陶瓷(LTCC)滤波器具有体积小、插损小和衰减大的特性,为了抑制其阻带信号,研究并设计了具有带外多个传输零点的多层LTCC带通滤波器,分析了传输零点对滤波器性能的影响.最后利用HFSS仿真软件设计了一个具有三级耦合谐振器、尺寸为2.5 mm×2.0 mm×0.9mm、中心频率为2.45 GHz的带通滤波器.仿真...     

Design and analysis of a structure-based microstrip bandpass filter

A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure （DGS） technology. A double-mode coupling resonator combined with DGS structure was used to achieve the resonance frequency and the filter size. CST microwave studio was used to optimize the attenuation performance to get the filter parameters. A structure-based passband filter was fabricated. Simulation is consistent with the measurement. Performance shows that the proposed filter could be suitable for the time division-long term devolution （TD-LTE） microwave systems at 2.6 GHz.