Tri‐band Microstrip Bandpass Filter Using Dual‐Mode Stepped‐Impedance Resonator

This letter presents a compact dual‐mode tri‐band bandpass filter by using a short‐circuited stub‐loaded stepped‐impedance resonator (SIR) and a short‐circuited stub‐loaded uniform impedance resonator. Also, a hairpin SIR geometry is introduced to miniature the size of this filter while maintaining excellent performance. The use of a short‐circuited stub at the central point of the hairpin SIR can generate two resonant modes in two passbands. Its equivalent circuit structure is analyzed by using the even‐odd mode theory. For demonstration purposes, a tri‐band filter for the applications of the Global Positioning System at 1.57 GHz, Worldwide Interoperability for Microwave Access at 3.5 GHz, and wireless local area networks at 5.2 GHz is designed, fabricated, and measured.     

基于方开环谐振器的双陷波超宽带滤波器

针对超宽带系统易受窄带信号干扰的问题,设计了一种可以抑制无线局域网络(WLAN)和卫星通信信号干扰的双陷波超宽带带通滤波器。该滤波器的主要谐振结构由T型枝节加载的多模谐振器组成,改进的T型枝节增加了两个传输零点,同时减小了滤波器尺寸;通过耦合方开环谐振器,实现了两个陷波特性,调节谐振器尺寸,可以得到所需的陷波频率。测试结果表明,该滤波器的尺寸仅16.7mm×8.5mm,中心频率为6.9GHz,通带为3.0~10.8GHz,陷波中心频率在5.8GHz和8.04GHz,衰减最低点分别为-27dB和-18dB,仿真与测量结果有较好的一致性。     

双阻带特性的超宽带单极子天线设计

设计了一种具有双阻带特性的超宽带单极子天线,对嵌入开路微带谐振器和边缘相似谐振器进行了分析.利用这两种谐振器可以分别在Wimax（3.33～6 GHz ）和WLAN（ 5.15～5.85 GHz）两个频段产生阻带.通过改变天线几何尺寸,可以分别对阻带的中心频率和带宽独立控制.天线利用印刷线路板（PCB）技术加工实现,并对其阻带特性、回波损耗、辐射方向图、辐射效率和峰值增益进行了测试,测试结果和仿真结果吻合很好.     

基于交指结构和双模谐振器的双频微带滤波器*

提出了一种应用于宽带系统和窄带系统的双频微带滤波器,其宽带通带和窄带通带分别通过三阶交 指型滤波结构和双模微带谐振器来控制。两部分的相互加载效应可进一步增强源-负载耦合,提高通带的选择性。 在50赘馈线上加载两个不同尺寸的反向四分之一波长谐振器(QWR)耦合短路枝节,可以在通带之间及上下边缘处 产生多个传输零点,提高了通带选择性和隔离度。最终,本文设计了一个工作于3.2GHz(宽带)和5.8GHz(WLAN) 的双频滤波器用以验证上述设计方法,测试和仿真结果吻合良好。     

新型高选择性双模宽带带通滤波器设计

首先利用阶梯阻抗谐振器和交叉耦合馈线结构设计了一种带宽达73．2％新型双模带通滤波器。该谐振器在通带内产生两个可调模式,馈线结构在阻带对称产生两个传输零点。接着在馈线上加载短路线,使原有的两个传输零点向截止频率靠近,并在上阻带新增一个零点,从而在保持原滤波器通带性能的同时提高了频率选择性和上阻带特性。通过对比两个滤波器S参数进一步验证改进效果。最后制作测试了该短路线加栽的滤波器,仿真和实测结果吻合良好。     

Dual mode wideband band-pass filter with notched band for communication system

This paper presents a planar microstrip wideband dual mode Band-Pass Filter (BPF) from 2 GHz to 3.4 GHz with a notched band at 2.62 GHz. The dual mode band-pass filter consists of a ring resonator with two quarter-wavelength open-circuited stubs at ?? =90° and ?? =0°, respectively. A square perturbation stub has been put at the corner of the ring resonator to increase the narrow stopbands and improve the performance of selectivity. By using a parallel-coupled feed line, a narrow notched band is introduced at the required frequency and its Fractional BandWidth (FBW) is about 5%. The proposed filter has a narrow notched band and a wide pass-band with a sharp cutoff frequency characteristic, the attenuation rate for the sharp cutoff frequency responses is 297.17 dB/GHz (calculated from 1.959 GHz with ?34.43 dB to 2.065 GHz with ?2.93 dB) and 228.10 dB/GHz (calculated from 3.395 GHz with ?2.873 dB to 3.507 GHz with ?28.42 dB). This filter has the advantages of good insertion loss in both operating bands and two rejections of greater than 16 dB in the range of 1.59 GHz to 1.99 GHz and 3.49 GHz to 3.98 GHz. Having been presented in this article, the measurement results agree well with the simulation results, which validates our idea.     

An Ultra-Wideband Bandpass Filter With an Embedded Open-Circuited Stub Structure to Improve In-Band Performance

In this letter, we present a compact ultra-wideband bandpass filter (BPF) with a notch band in the BPF performance by using an embedded open-circuited stub structure. The filter mainly consists of conventional stepped impedance resonator (SIR) as the multiple-mode resonator and two enhanced coupled input/output lines. The bandwidth can be analyzed by using the image-parameter method to obtain the proper dimension of the coupled lines and verified by using electromagnetic (EM) simulation. The embedded open-circuited stub structure in the SIR is used to produce a narrow notched band at 5.8 GHz, which its frequency position and bandwidth can be tuned by its physical parameters. The measured 3 dB fractional bandwidth of 113.8% and narrow notched band with 25 dB rejection is achieved. Good agreement between the EM simulation and measurement is obtained.      

Compact Dual Band Transversal Bandpass Filter With Multiple Transmission Zeros and Controllable Bandwidths

A compact microstrip dual band transversal bandpass filter (DBTBPF) using short-circuited stub loaded half-wavelength resonator and stepped impedance resonator is proposed. Multiple transmission zeros are created to improve the selectivity of the DBTBPF. Furthermore, the bandwidths of the proposed filter can be regulated in a relatively wide range. Two 2.4/5.2 GHz DBTBPFs with 192 MHz and 120 MHz absolute equal bandwidths, respectively, are designed. The measured results agree well with the simulations.      

Quad‐Band Bandpass Filter Using Quad‐Mode Stub‐loaded Resonators

Compact multi‐band bandpass filters using quad‐mode stub‐loaded resonators are proposed in this letter. Firstly, a novel approach about the mode‐splitting characteristics of the quadruple‐mode resonator is investigated, which can provide dual‐band behavior. Secondly, a quad‐band filter is proposed and designed by cascading two quadruple‐mode resonators; the upper one operates at 1.8/2.4 GHz (GSM‐ and WiMax‐band) and the lower one at 1.57/2.1 GHz (GPS‐ and WCDMA‐band). Finally, the proposed filters have been fabricated. Respectable agreement between simulation and measurement verifies the validity of this design methodology.     

New compact ultra wideband bandpass filter using modified multi-mode resonator

A new compact ultra wideband (UWB) bandpass filter (BPF) using modified multi-mode resonator (MMR) is presented. The filter consists of a multi-mode resonator with dual spur-lines for providing the dual notch bands at 5.2 and 5.8 GHz and connected with a stepped impedance structure for controlling the transmission zeros at lower and higher passband edge. The interdigital coupling input/output (I/O) lines are used for coupling enhancement. The |S₂₁|-magnitude and the frequencies of notch bands can be well determined by tuning the dimensions of the dual spur-lines. The designed procedures are discussed and good agreement between the measurement and EM simulation are compared.     

Tunable MEMS LC resonator with large tuning range

A tunable resonator based on MEMS technology is reported. The resonator is a parallel LC type resonator, in which the capacitor is made up of two metal bridges and the inductor is made up of a shorted stub. The length of the shorted stub is changed by shunt DC contact switches and therefore inductance values of the resonator can be varied. As a result, the resonant frequency of the resonator can be shifted from 8 to 14 GHz with 75% tunable range. The whole size of the resonator is 6/spl times/0.9 mm/sup 2/.     

A Novel Microstrip Filter Using Three-Mode Stepped Impedance Resonator (TSIR)

A novel microstrip filter using three-mode stepped impedance resonator (TSIR) is presented, with its coupling scheme given so as to accurately predict its desired performance. A T-type open stub is introduced into the design of a miniaturized TSIR. It is shown that the developed filter exhibits quasi-elliptic characteristics with sharp skirt and wide stopband. Good agreements are obtained between its measured and simulated S-parameters.      

宽阻带超宽带带通滤波器的设计

提出了一种新型结构的超宽带带通滤波器。这种滤波器结构基于最优的短路支节传输线滤波器,短路支节之间的连接线替换成一种层叠结构的阶跃阻抗发夹线。阶跃阻抗发夹线谐振器的低通滤波性能较好地实现了滤波器的阻带衰减,而对滤波器的通带传输特性影响小。由于阶跃阻抗发夹线的慢波特性,滤波器的尺寸在长度上缩减了23%,其结构更加紧凑。     

New Design Equations for a Class of Microwave Filters (Correspondence)

New approximate design equations for a class of microwave bandpass filters are presented. The filters are 1) dual forms of half-wave parallel-coupled resonator filters, 2) one form of interdigital filter, and 3) dual forms of direct-coupled stub filters. The advantages derived from using the new equations are 1) exact realization of the specified design bandwidth and 2) improved pass-band voltage standing-wave ratio (VSWR) response in the vicinity of band edge. Experiments data are presented for a trial filter design having 7 resonators, 40-percent bandwidth, and passband VSWR of 1.2.     

基于多向馈电耦合的折叠小型化三带通滤波器

基于奇偶模理论,通过多向馈电耦合的方式,在十字形双频带通滤波器(DBPF)的基础上,研究并设计了一种十字形枝节折叠的双馈线三通带通滤波器(TBPF)模型。结构分析表明,该模型具有三频中心频率灵活独立可调,结构易级联,小型化和频率设计参量少的特点。仿真结果表明,增加的馈电方向激励起滤波器的第三通带,设计的TBPF在5G通信的中低频段和室内WiFi低频段具有良好的特性。文献比较显示,提出采用的多向馈电设计方法,减少了谐振器结构复杂度和频率设计参数个数,同时,该法对基础谐振器通带频段的增加有一定启示意义。     

毫米波双通带基片集成波导滤波器设计

提出了一种新型毫米波双通带基片集成波导(SIW)滤波器,该滤波器由双模基片集成波导和双模带线谐振器构成。其中双模带线谐振器嵌入到双模基片集成波导谐振腔中,不占据额外的电路面积,利用双模带线谐振器的TEM模和双模基片集成波导谐振腔的两个简并模式TE102、TE201,可分别形成两个相互独立的通带,因此该滤波器的设计具有很大的灵活性。所设计的双通带滤波器具有三个传输零点,实现了良好的带外抑制和带间隔离度。该双通带滤波器工作于28.4GHz和32.2GHz,3dB带宽分别为2%和3%。最终的测试结果和仿真结果相吻合,证明了该设计方法的可靠性。     

Metamaterial inspired quad band circularly polarized antenna for WLAN/ISM/Bluetooth/WiMAX and satellite communication applications

A CPW fed metamaterial inspired Quadband circularly polarized antenna is presented in this article. The proposed antenna consists of defected ground structure with a radiating stub, which is at opposite side of the feedline. A waveguide mode of analysis is carried out for split ring resonator (SRR) and complimentary split ring resonator (CSRR) to enhance the properties of metamaterials. The proposed antenna analysis is taken iteration wise and used FR-4 Material as the substrate material with Ɛ_r = 4.4 and analysed using ANSYS electromagnetic desktop. The designed antenna projecting the peak gain of 4.8 dB and it is working in the application bands of WLAN/ISM/Bluetooth at 2.4 GHz, 5.8 GHz and 3.35 WiMAX band, X-band downlink satellite communication system (7.25–7.75 GHz) and ITU band (8–8.5 GHz) with fractional bandwidth of about 70%. Proposed antenna exhibits circular polarization at 2.39–2.55 GHz, 3.05–3.1 GHz, 4–5 GHz and 6.3–6.64 GHz respectively. To know the signal integrity of the antenna, time domain analysis is carried out for identical antennas in two conditions (face to face and side by side) with the help of CST microwave studio. The designed antenna showing excellent correlation in measurements with respect to simulation results.     

基于CSRR 改进的双陷波超宽带天线

针对超宽带系统易受窄带信号干扰的问题,提出了一种基于互补金属开口谐振环(CSRR)改进的双陷波超宽带缝隙天线。在现有文献中,单个CSRR只能实现单陷波功能,要想增加陷波频段,只能通过增加CSRR个数的方法来实现,这就增加了设计的复杂性。通过天线辐射贴片上的表面电流分布图分析了CSRR内外环与两个陷波频段的对应关系。对所设计的超宽带天线进行了制作和测量,实测结果与仿真结果吻合较好,证明了该设计方法的正确性。     

基于CSRR-QMSIW谐振器的双通带滤波器的设计

为满足滤波器在双频带通信系统中发展的要求,提出了一种基于1/4模基片集成波导(QMSIW)加载互补开口谐振环(CSRR)的新型双通带滤波器。根据CSRR谐振器的传输特性,实现以其谐振频点为中心的第一个通带;设计QMSIW谐振腔的边长,实现以该腔体谐振频点为中心的第二通带;设计QMSIW腔体间的耦合方式,在两通带之间和高阻带处各引入一个传输零点,加强两通带隔离度和带外抑制。设计了一款两通带的中心频率分别为8.1 GHz和11.5 GHz,且有效尺寸仅为15 mm×8 mm,插入损耗低于0.4 dB,高阻带衰减达64 dB,两通带隔离度达46 dB。     

“凸”型谐振结构双频滤波器分析

滤波器作为射频收发机中不可缺少的关键器件,双频或多频滤波器已成为研究重点。文中提出了一种新型的“凸”型谐振结构,利用该谐振结构研制出一种双频带滤波器,并对其谐振结构进行了建模仿真。采用弱耦合的方式对结构的谐振模式进行分析,在该谐振器下方中央位置加载一段开路枝节,对该谐振器选取合适的耦合方式进行馈电,研制出一种新型双频滤波器,并进行滤波器实物加工和测试,验证了该方法的正确性。