一种具有边带陡峭特性的超窄带滤波器

应用LTCC技术,设计了一款带通滤波器。采用开口环谐振结构作为基本谐振单元,利用谐振级之间的耦合产生传输零点,实现边带抑制。给出了开口环谐振结构的等效电路分析,滤波器的通带中心频率为23.2 GHz,3-dB带宽为600 MHz,具有很窄的相对带宽,3-dB相对带宽仅为2.6%。对滤波器进行仿真和优化,结果表明,通带22.9~23.5 GHz内插损小于3 dB,低阻带10~21.1 GHz的衰减大于45 dB,高阻带25.3~40 GHz的衰减均大于30 dB。该滤波器的尺寸为4 mm×3.5 mm×0.45 mm,具有非常好的窄带特性和边带抑制特性。     

横向双模双频滤波器设计

基于横向滤波器耦合结构,采用支节加载双模谐振器,设计了中心频率位于1.57 GHz(GPS应用)与2.4GHz(WLAN应用)的双频微带滤波器。由短路支节加载双模谐振器形成第一个通带,开路支节加载双模谐振器形成第二个通带,两个谐振器被输入/输出馈线隔离,每个通带的中心频率与带宽可以单独调节。测试结果表明:两个通带内的最小插损分别为2.18,1.35 dB,3 dB带宽分别为5.2%,6.8%,回波损耗均小于16 dB,三个传输零点分别位于1.28,2.08,2.71 GHz处。该滤波器具有尺寸小、带外选择性好等优点。     

基于非对称互补开口谐振环的基片集成波导带通滤波器

本文提出了一种新颖简单的结构用于设计具有良好带外抑制能力的单通带和双通带滤波器。在矩形基片集成波导谐振腔的接地面上设计了一对非对称的互补谐振环,使其在单通带滤波器下作为一个微扰元件,在双通带滤波器下作为一个谐振元件。本文提出了一种在不改变整个腔体尺寸的前提下,仅通过调整非对称互补谐振环的相对位置来实现单通带和双通带转换的新方法。此外,通过抑制高阶模式实现宽阻带性能,并通过引入有限的传输零点来提高带外抑制能力。为了验证该设计的可行性,本文设计,加工并测试了中心频率为11.075GHz,带宽为750MHz的单通带滤波器和中心频率为11.45GHz,14.25GHz,带宽均为500MHz的双通带滤波器。测量结果表明通带内回波损耗均大于13dB,插入损耗小于1.5dB。测试结果与仿真结果基本一致。     

基于开路T型结构的小型化超宽阻带滤波器设计

传统滤波器由于寄生通带的存在,其高频阻带性能较差。随着超宽带雷达系统和超宽带通信系统的发展,小型化宽阻带的滤波器已成为一项紧迫的技术课题。该文论述了一种普适性的基于开路T型结构的小型化超宽阻带滤波器结构,这种滤波器和传统滤波器相比,结构极为紧凑,5倍基频范围内的寄生通带均被抑制,而通带性能保持良好。基于此结构实际制作了一个截止频率为2.9 GHz的低通滤波器,测量得到的通带内平均插入损耗仅0.67 dB,带内平均驻波比为1.33,过渡带陡峭,40 dB矩形系数仅1.096,而所测得的阻带从3.23 GHz到10.30 GHz之内谐波抑制大于36 dB,从10.30 GHz到15 GHz之内谐波抑制大于27 dB;该滤波器的长度仅为传统的同类型滤波器的长度的37.1%,面积大大减小。仿真和测量结果表明该类型滤波器同时满足了小型化和宽阻带的性能需求。     

多口三环CSRR微带低通滤波器的研究与设计

提出一种新型的多口三环CSRR结构,利用CSRR谐振器的单极点低通特性和环与微带线之间的耦合,构成低通滤波器.分析该结构的等效电路模式,指出谐振频率的计算公式.使用HFSS适当优化参数,可以得到性能良好的低通滤波器.其-3 dB截止频率8.76 GHz,通带内插入损耗小于0.3306 dB,通带内回波损耗小于-13.810 2 dB,衰减15 dB以上阻带带宽达到10.31 GHz.为了改善通带内的回波损耗,在微带线两侧加载并联开路枝节.其-3 dB截止频率8.385 GHz,通带内插入损耗小于0.174 7 dB,通带内回波损耗小于-19.707 7 dB,衰减15 dB以上阻带带宽达到10.7 GHz.     

基于DGS 结构的微带岔线型带通滤波器设计

本文介绍了一种基于缺陷地结构(DGS)的微带岔线型宽带带通滤波器的设计过程。此滤波器以四分之一波长的开路枝节型带通滤波器为原型进行设计和改进,引入了微带岔线和DGS 结构,在增加通带带宽和阻带带宽的同时,使滤波器的带外谐波抑制和带内回波损耗得到了很大的改善。采用HFSS 三维场仿真软件进行S 参数的仿真,从仿真结果可 以看出,所设计的带通滤波器中心频率为11.5GHz,其3dB 相对带宽大于50%,带内插损小于0.3dB。此外,在1-6GHz的第一阻带内,滤波器的带外抑制大于20dB,最大抑制度为52dB;在15-24GHz 的第二阻带内滤波器的带外抑制大于20dB,最大抑制度为46dB。整个滤波器尺寸仅为12mm × 16mm。     

新型小型化平衡滤波器的设计

结合平衡滤波器性能与LTCC(Low Temperature Co-fired Ceramics)工艺,从滤波器和巴伦的设计理论出发,设计了一款新型小型化的高性能平衡滤波器。该平衡滤波器采用多层带状线结构作为基本的谐振单元同时实现滤波和巴伦功能。仿真结果表明,该平衡滤波器的通带中心频率为4.05 GHz,3 dB带宽为300 MHz,通带3.9~4.2 GHz内插损小于5.5 dB,低阻带1.0~3.5 GHz和高阻带5~8 GHz的衰减均大于30 dB,幅度不平衡度小于±0.25 dB,相位不平衡度小于±6°,平衡滤波器尺寸为3.2 mm×2.5 mm×1.5 mm。     

基于T型分支线结构的小型化差分滤波器

基于T型分支线结构设计了两种新型的小型化差分滤波器,一种是单通带滤波器,另一种是双通带滤波器。其中,单通带滤波器在中心对称线处增加开路支节,构成T型分支结构,可以实现良好的共模抑制。为了验证上述的理论分析,本文设计两个滤波器(ε_r=2.65,h=1mm),单通带滤波器的差模通带中心频率f0为2.5GHz,阻带范围为3.1~9.7GHz,-3dB相对带宽为14.7%(2.2~2.8GHz);双通带滤波器的差模通带中心频率分别为2.2GHz和6.4GHz,-3dB相对带宽分别为18.2%(2~2.4GHz)和9.2%(6.2~6.8GHz)。实测结果与理论预期一致。     

基于双模谐振器的双通带可调谐滤波器设计

从理论上分析了开路支节加载双频谐振器的谐振模式,通过在谐振器末端加载变容二极管的方式,设计了一款双通带独立可调谐滤波器。通过调节谐振器末端变容二极管电容值大小来改变通带的中心频率,通过调节支节末端的变容二极管来调节通带的带宽。该滤波器的两个通带之间相互独立,调谐其中一个通带对另一个通带几乎没有影响。通过引入源与负载的耦合,使得双通带两侧各产生一个传输零点,提高了滤波器的选择性和带外抑制能力。最终设计出的滤波器第一通带的中心频率在1.08~1.19 GHz之间连续可调,绝对带宽在112~152 MHz之间连续可调;第二通带中心频率在2.07~2.22 GHz 之间连续可调,其绝对带宽在132~189 MHz 之间连续可调。在调谐过程中,通过调节中心开路支节末端变容二极管加载直流电压大小,实现调谐过程两通带带宽基本维持不变。     

宽阻带平面低通滤波器的设计

低通滤波器是通信系统中关键的器件之一,常作为选频器件用来抑制干扰信号和谐波信号,因此低通滤波器阻带带宽成为关键指标.常见的平面低通滤波器采用短截线(分支线)或高低阻抗线结构,这些结构的低通滤波器阻带不够宽,一般在截止频率的2倍频或3倍频处出现寄生通带.本文使用等效的T形节替代低通滤波器中的串联传输线的方式实现了带阻滤波器嵌入到低通滤波器内部,既对低通滤波器的阻带上任意频段出现的寄生通带进行了抑制,又不影响低通滤波器的通带内性能,并给出等效T形节的综合设计公式.此结构综合设计方法严谨简单、易于平面电路实现,制作出来改进的低通滤波器对3倍频寄生通带进行抑制,扩宽了阻带带宽到4个倍频程以上,测试结果:通带带宽0~3GHz,通带插入损耗小于0.5dB,带外抑制3.6~12GHz大于60dB.     

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.     

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.     

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 UWB bandpass filter using ring open stub loaded multiple-mode resonator

A novel ultra-wideband (UWB) bandpass filter with a compact size, improved upper-stopband performance and reduced radiation loss has been studied and designed using a multiple-mode resonator (MMR). The MMR is formed by attaching three pairs of ring open stubs in shunt to a high impedance microstrip line. By simply adjusting the radius of the circles of the ring stubs, the resonant modes of the MMR can be roughly allocated within the 3.1?10.6 GHz UWB band while suppressing the spurious harmonics in the upper-stopband. Meanwhile, the insertion loss is higher than 20.0 dB in the upperstopband from 11.7 to 33.5 GHz in simulation. Finally, the filter is fabricated and measured. The EM-simulated and measured results are presented and excellent agreement between them is obtained.     

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.     

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.     

基于枝节加载开环谐振器的带阻滤波器设计

提出了一种具有良好谐波抑制功能的双枝节加载开环谐振器,加载枝节采用均匀阻抗结构,与同尺寸的开环谐振器相比,结构更紧凑,能够更好地抑制寄生模,而且可以达到更低的谐振频率。分析了加载枝节参数对带阻滤波器抑制二次谐波的影响。通过在加载的双枝节间引入集总可变电容,可以使谐振器具备谐波抑制性能的同时,实现中心频率可调的功能。基于双枝节加载环谐振器设计出一种可调带阻滤波器,中心频率可以在900MHz ~2. 65GHz 范围内调节,而且最低寄生阻带能够抑制到8GHz。     

The Design of Coupled Resonator Bandpass Filter With Wide Stop-Band

A compact four-pole bandpass filter with multi-order spurious response suppression is proposed. The combination of dissimilar resonator structures with the same fundamental frequency but with different spurious frequencies may improve the stop-band rejection by the mutual cancellation of spurious responses. The measured results show that better than -20 dB rejection levels in the stop-band up to 4.5 f₀ have been obtained. Moreover, an embedded-resonator topology is used, which makes the structure of filter to be more compact.     

微型化Ka波段环形带线谐振腔LTCC带通滤波器

提出了一种微型化Ka频段带线带通滤波器设计方案.采用带有调谐枝节的环形谐振腔和带线耦合结构,利用低温共烧陶瓷(LTCC)技术设计并研制了一个相对带宽约10.4%的Ka频段带通滤波器,典型性能为在中心频率26.99 GHz处插入损耗小于1.3 dB,带内驻波比小于1.20:1,损耗起伏小于0.30 dB,滤波器的尺寸为4...     

Design of low-pass filter with 3-interations Koch fractal Pi-shaped DGS

A novel asymmetrical Pi-shaped defected ground structure (DGS) with 3-interations Koch fractal curves is proposed to design a microstrip low-pass filter (LPF) with ultra-wide stop-band (SB). The proposed LPFs with a single resonator and two cascaded resonators are both designed, simulated, manufactured and measured. Simulation and experiment results demonstrate that the designed LPF has a very sharp transition band (TB) and an ultra-wide SB performance compared with the existed similar symmetrical and asymmetrical DGS. The proposed LPF with two cascaded resonators is with a compact size of 36.8 mm×24.0 mm, a very low insertion loss of less than 0.7 dB under 1.9 GHz, and a wide SB from 2.2 GHz to 8 GHz with rejection of larger than 30 dB.