A wideband stepped-impedance rectangular-ring resonator bandpass filter with multiple notched bands

A configuration of wideband bandpass filter (BPF) with multiple notched bands is presented. Proposed BPF is based on stepped-impedance resonator. By utilising dual stepped-impedance resonators in folded topology a rectangular-ring resonator is formed. Two notched bands in the passband are achieved without using asymmetrical coupled lines. In other words, the filter configuration is capable of producing notched bands. It should be noted that additional information on filter performance and design is presented. Measurement results are presented to approve propounded filter characteristics. The measured passband of the second proposed filter is from 3.68 to 10.2 GHz with insertion loss of –1.76 dB in the first passband at the centre frequency of 4.45 GHz. The measured notched band frequencies are about 5.45 and 7.95 GHz with rejection of –21.77 and –20.82 dB, respectively. The return loss in the passband is better than –11.4 dB.     

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.      

Microstrip Lowpass Filter with Very Sharp Transition Band and Wide Stopband

A novel lowpass filter with a very sharp transition band and wide stopband is proposed. The proposed filter is based on T‐shaped patches which are etched in symmetrical structures and folded open stub. To obtain a wide stopband, we have used stub loaded semi‐circle stepped‐impedance structures. By designing the resonator with high inductance and capacitance, a very sharp transition band is achieved. The proposed filter has a 3‐dB cutoff frequency at 2.37 GHz and a 40‐dB rejection at 2.44 GHz. The stopband with an attenuation level better than –13.2 dB is up from 2.4 GHz to 16 GHz, and consequently we have reached the high and wide rejection in stopband with compact size. Good agreements between the simulated and the measured results are presented.     

一种新型超宽带带通滤波器的设计

针对超宽带(UWB)系统易受无线网络信号干扰及传统的超宽带带通滤波器阻带较窄,不能有效抑制谐波的问题,提出了一种新型的UWB带通滤波器,该滤波器由两级交指梳状耦合谐振器级联组成,通过增加耦合指的个数来实现陷波特性,然后在两个交指谐振器的中间添加一个槽线锥形谐振器,使该滤波器具有抑制高次谐波特性,达到拓宽高阻带的效果,同时由于槽线谐振器的加入,陷波频段的抑制电平进一步提高.实验结果证明,所设计的滤波器既能保证3.1～10.6 GHz频段内的插入损耗小于3 dB,陷波频段为5.7～5.8 GHz,陷波频段的抑制电平高达-43 dB,同时又能拓宽高频阻带.     

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。     

Microstrip Lowpass Filter with Very SharpTransition Band Using T‐Shaped,Patch, and Stepped Impedance Resonators

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of ?3 dB and ?20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3‐dB cut‐off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than ?20 dB is obtained while achieving a compact size with a wide stopband.     

基于双层扇形基片集成波导的双频平衡滤波器

提出了一种表面刻有一对互补开环谐振器(CSRR)的45°扇形基片集成波导谐振腔(SSIWR),设计并制作了一款结构紧凑且具有高选择性的双层双频平衡带通滤波器.分别利用具有带通特性的CSRR和谐振腔内的TM220模实现了差模双频响应;模式间的耦合以及缺陷地结构(DGS)的引入使得滤波器在通带附近产生4个传输零点,提高了带...     

Design of compact, broad-stopband lowpass filter using modified stepped impedance hairpin resonators

A compact elliptic function lowpass filter using a stepped impedance hairpin resonator is proposed. The filter has the advantages of compact size, low insertion loss, easy fabrication, a wide stopband, and sharp cutoff frequency response. In order to cause a sharp cutoff frequency response and the wide stopband suppression, a coupled stepped impedance resonator is taken into consideration for the newly proposed lowpass filter. A demonstration filter has been designed, fabricated and tested, and the results agree well with the theory. The size of the filter is less than 0.037 lambdag times 0.093 lambdag, where lambdag is the waveguide length at the cutoff frequency 1.5 GHz, and the 10 dB rejection stopband can be extended to more than 15 GHz. The filter is useful for many microwave system applications.     

A novel microstrip lowpass filter with sharp roll-off and ultra-wide stopband using SICMRC

This paper presents a novel microstrip lowpass filter with sharp roll-off and ultra-wide stopband using stepped-impedance resonator and bended transmission line structure. The filter includes stepped-impedance prototype filter and stepped-impedance compact microstrip resonator cells that are combined in one structure. The proposed filter has good specifications such as sharp roll-off, ultra-wide stopband and low insertion loss. The transition band is approximately 0.25 GHz from 1.75 to 2 GHz with corresponding attenuation levels of ?3 and ?40 dB. The attenuation level in the stopband is better than ?20 dB that is achieved from 1.94 to 23 GHz, and the insertion loss in the passband is less than 0.4 dB. The proposed filter is fabricated and measured, and the simulation and measurement results are found to be in good agreement with each other.     

基于阶梯阻抗发夹谐振器的小型低通滤波器

提出一种基于阶梯阻抗发夹谐振器的小型化微波低通滤波器,该滤波器仅由包含一节微带线的阶梯阻抗发夹谐振器构成。设计结果表明,滤波器3dB通带从DC(Direct Current)到2GHz,回波损耗优于10dB,且插入损耗从DC到1.7GHz时优于0.5dB,带外抑制从2.9～4GHz优于20dB。仿真结果和实验结果吻合良好。这种滤波器尺寸小,易制造,且具有陡峭的截止频率响应特性,可应用于许多微波系统中。     

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。     

Wide-stopband microstrip low-pass filter using modified semi-circle patch resonator

In this article, a compact microstrip low-pass filter with elliptic-function response is proposed. To achieve wide stopband, modified semi-circle patch resonator in series with semi-circle stepped impedance resonator is used. The proposed structure achieves a wide stopband and a high selectivity within a small circuit area. The proposed filter has 3-dB cutoff frequency at 1.71?GHz and 20?dB rejection at 2.1?GHz. The stopband with the attenuation level better than ?18.7?dB is from 2.08 up to 16?GHz, and consequently we have reached the high and wide rejection in stopband as well as compact size. The structure is simulated, fabricated and measured. The measured results are in good agreement with the simulated results.     

Compact microstrip lowpass filter with very sharp roll-off using meandered line resonators

In this paper, a new compact size microstrip lowpass filter (LPF) with a very sharp roll-off is presented to apply in the modern wireless networks. The proposed LPF is designed using the series main resonators with meandered lines based on inductor-capacitor (LC) equivalent circuit analysis. The main goal is to achieve maximum-sharp roll-off by maintaining a wide stopband bandwidth and high return loss (RL). The main resonator of the proposed filter is consisted of two meandered line hairpin resonators (MLHR), and a meandered line T-shaped resonator (MLTR). The designed suppressor is composed of two coupled radial stubs to create a wide stopband. Low return loss in the passband, which has been created by the main resonator, is resolved by the suppressor structure with high return loss. The measured results show a ??3 dB cut-off frequency of 1.93 GHz. The very sharp transition band starts at 1.93 to 1.97 GHz (from ??3 to ??20 dB). The stopband is from 1.97 to 19.9 GHz (with the suppression level of ??20 dB). Also, the total size of the proposed LPF is only 13.3?×?10.1 mm².

     

Compact UWB monopole antenna with quadruple band notched characteristics

ABSTRACT

A compact planar Ultrawideband (UWB) monopole antenna with quadruple band notch characteristics is proposed. The proposed antenna consists of a notched rectangular radiating patch with a 50 Ω microstrip feed line, and a defected ground plane. The quadruple band notched functions are achieved by utilising two inverted U-shaped slots, a symmetrical split ring resonator pair (SSRRP) and a via hole. The fabricated antenna has a compact size of 24 mm × 30 mm × 1.6 mm with an impedance bandwidth ranging from 2.86 to 12.2 GHz for magnitude of S₁₁ < ?10 dB. The four band notched characteristics of proposed antenna are in the WiMAX (worldwide interoperability for microwave access) band (3.25–3.55 GHz), C band (3.7–4.2 GHz), WLAN (wireless local area network) band (5.2–5.9 GHz) and the downlink frequency band of X band (7–7.8 GHz) for satellite communication are obtained. The measured and simulation results of proposed antenna are in good agreement to achieve impedance matching, stable radiation patterns, constant gain and group delay over the operating bandwidth.     

Compact lowpass filters with very sharp transition bands based on open complementary split ring resonators

It is shown that open complementary split ring resonators (OCSRRs) are useful particles for the design of lowpass filters with very narrow transition bands in microstrip technology. Owing to the small electrical size of OCSRRs, the filters are also very small. These filters are implemented by cascading several OCSRR stages in a microstrip line. The OCSRR stages can be modelled as parallel resonators in series configuration, thus providing a transmission zero at their resonance frequency. By designing the OCSRRs with small inductance and high capacitance, very sharp cutoffs are achieved. To illustrate the possibilities of the approach, a prototype device example is provided. It consists on a five-stage periodic microstrip lowpass filter with 3 dB insertion losses at 1.33 GHz and 40 dB rejection at 1.45 GHz. To improve out-of-band rejection, four additional OCSRR stages tuned at the spurious frequency band have been cascaded. Filter dimensions are 39 x 7.4 mm (i.e. 0.46l x 0.087l, where l is the guided wavelength at the cutoff frequency). These filters are of interest in applications where small size and severe cutoff requirements are required.     

基于扇形基片集成波导的三频带通滤波器设计

该文提出了一种60°扇形基片集成波导谐振器,然后在谐振器中加载一排金属通孔,对其TM110、TM210和TM120模进行扰动,最后利用扰动后的场模式,在60°扇形基片集成波导谐振器的基础上设计了一款结构紧凑的三频带通滤波器。通过分别引入互补开口环谐振器和源 负载耦合结构,改善了滤波器的频率选择特性。3个通带的中心频率分别为5.61 GHz、7.41 GHz和8.77 GHz,3 dB带宽分别为148 MHz、298 MHz、347 MHz。滤波器的测试与仿真结果基本吻合。     

一种基于正方环形谐振器的新型宽带带通滤波器

本文设计了一种紧凑型、宽通带、宽阻带的微带带通滤波器。该滤波器的设计是基于带有两个开路调节支节的正方谐振环。基于紧凑性的考虑,改变了传统方环谐振滤波器的馈电点和开路调节支节的位置,以便对谐振环进行折叠处理。这种改变并不影响谐振环的奇偶模特性。在输入和输出端口,通过两个叉指耦合结构对滤波器进行馈电,这种馈电方式增加了滤波器阻带的带宽和抑制度。滤波器的中心频率为4GHz,相对带宽为45％,通带内的回波损耗小于-12dB,群时延小于0．8ns,1-2．9GHz阻带抑制度大于12dB,5．3～7GHz阻带抑制度大于18dB。     

Compact wide stopband lowpass filter using spiral loaded tapered compact microstrip resonator cell

A new spiral loaded tapered compact microstrip resonator cell (SPLT-CMRC) is presented. The addition of spiral stubs to the CMRC creates transmission zeroes in the stopband which extended the stopband of the ?lter. The proposed resonator is used to design a compact lowpass ?lter (LPF) with wide and high rejection in stopband. The fabricated ?lter has a 3 dB cutoff frequency at 8 GHz. The insertion loss in the passband is less than 0.2 dB from DC to 7.2 GHz. The proposed ?lter has wide stopband from 9.47 to 40 GHz with attenuation level of ?20 dB. The demonstrated filter is designed and fabricated. There is a good agreement between the measured and simulated S-parameters.     

Precise Design of a Bandpass Filter Using High-Q Dielectric Ring Resonators

A precise design is presented for a bandpass filter constructed by placing TE/sub 01delta/ dielectric ring resonators coaxially in a TE/sub 01/ cutoff circular waveguide. On the basis of a rigorous analysis by the mode- matching technique, the interresonator coupling coefficients are determined accurately from the calculation of two resonant frequencies f/sub sh/ and f/sub op/ when the structurally symmetric plane is short- and open-circuited. For the TE/sub 01delta/ ring resonator,the resonant frequency f/sub 0/, the temperature coefficient tau/sub f/, the unloaded Q(Q/sub u/), and the other resonances are also calculated accurately in a similar way. From the calculations, the optimum dimensions are determined to obtain the maximum Q/sub u/, as F/sub r/ = f/sub r/ /f/sub 0/ is kept constant, where f/sub r/ is the next higher resonant frequency the ring resonator using low-loss ceramics (epsilon/sub r/ = 24.3, tan delta = 5 x 10/sup -5/) has Q/sub u/ = 16800 at 12 GHz and tau/sub f/ = 0.1+-0.5 ppm/° C, while the rod one has Q/sub u/ = 14700. A four-stage Chebyshev filter having ripple of 0.04 dB and equiripple bandwidth of 27.3 MHz at f/sub 0/ =11.958 GHz is fabricated using these resonator; the measured frequency responses agree well with theory. The insertion loss is 0.9 dB, which corresponds to Q/sub u/ = 9800.     

基于方环形谐振器的超宽带滤波器设计

基于方环形谐振器设计了一款超宽带滤波器.输入/输出馈线与谐振器间采用零度馈电方式以增强滤波器的整体耦合.实测结果显示,该超宽带滤波器带内最小插损约为-1.93dB,最大回波损耗约为-9.45dB,相对带宽达到110%,在12.70GHz附近存在一个传输零点,改善了滤波器的选频性能及杂散抑制性能.实测结果与仿真结果较为吻合.