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.     

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.     

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.     

一种新颖的开口环地面缺陷结构低通滤波器

提出了一种新颖的具有陡峭边带和宽阻带的小型化低通滤波器.通过把开口谐振环地面缺陷结构(Split-Ring Resonator Defected Ground Structure,SRR DGS)与阶梯阻抗梳状谐振器结合,提高了滤波器的选择特性,同时获得了宽阻带.对所提出的结构作了加工并进行了实物测量,测试结果表明:滤波器选择特性大于160 dB/GHz,在2.98 GHz到8.2 GHz范围内抑制度大于20 dB,而占用面积仅为20×25 mm~2.     

Compact and high-performance bandpass filter and diplexer based on SCMRC-loaded SIR

Bandpass filter (BPF) and diplexer, which are required to be compact size and high performance, are widely used in modern wireless communication systems. In this article, novel BPF and diplexer are designed using the proposed resonator called spiral compact microstrip resonator cell (SCMRC)-loaded stepped-impedance resonator (SIR). The SCMRC-loaded SIR is proposed using the slow-wave structure SCMRC to replace the low-impedance section of the conventional SIR. Compared with the conventional SIR, the new SCMRC-loaded SIR has a compacter size and can generate a transmission zero above its fundamental resonant frequency. As examples, a BPF with the central frequency at f ₀?=?1?GHz and a diplexer operating at 0.9/1.57?GHz are designed and fabricated. The fabricated BPF occupies a compact size of 0.07 λ ₀?×?0.035 λ ₀ and has a??60?dB rejection level wide stopband from 1.2 f ₀ to 3.8 f ₀. The fabricated diplexer occupies a compact size of 0.076 λ ₀?×?0.128 λ ₀ and has an up to??50?dB output isolation. Good agreement can be observed between the simulations and the measurements.     

Design and analysis of a super compact wide-band bandpass filter based on metamaterial resonators

In this paper, a novel compact wide-band bandpass filter (BPF) with a wide frequency range is presented. This filter consisting of a multi-mode resonator (MMR) and four metamaterial unit-cells benefits from a very compact size. Unit-cells based on a complementary spiral resonator (CSR) including a metallic via, improve both upper and lower stopband rejection and compensate the insertion loss (I.L) within the passband altogether. This wide-band filter presents a 3-dB bandwidth of 7.7 GHz, ranging from 3 GHz to 10.7 GHz and the Insertion loss is less than 0.7 dB over the passband. The measured results are in good agreement with both the full-wave electromagnetic simulation and the proposed circuit model results. The dimension of the fabricated filter is 0.128 λ × 0.1 λ (i.e., 5.6 × 4.4 mm²). This filter is considerably compact compared to the other wide-band bandpass filters with the same substrate.     

Compact microstrip lowpass filter with wide stopband and sharp roll-off using tapered resonator

In this article, a novel microstrip lowpass filter (LPF) with specifications such as sharp cut-off, wide stopband, low insertion loss and high return loss using tapered resonator is presented. The LPF has cut-off frequency of 1.11 GHz, where unwanted harmonics are suppressed by novel tapered cells. The bandwidth is enhanced, and the size is reduced as compared to the conventional tapered filter. The transition band is approximately 0.29 GHz from 1.11 to 1.4 GHz with corresponding attenuation levels of –3 and –20 dB, respectively. The stopband with greater than –20 dB rejection is from 1.4 to 8.9 GHz, insertion loss in the passband is less than 0.1 dB, return loss is less than –18 dB and the overall size of the filter is 0.12 × 0.073 λ_g. The proposed filter is fabricated and measured. The simulation and measurement results are in good agreement. This LPF is designed for microwave communication applications, especially wireless video transmitters.     

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.     

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.

     

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.     

小型化宽频带宽阻带微带滤波器的设计

目前研究宽频带微带滤波器的文献很多,但普遍不能同时具有宽频带和宽阻带的性能,且带内回波损耗大,带外抑制差。为此,提出了一种新型的宽频带微带滤波器。该滤波器采用在E型阶跃阻抗谐振器( SIR)中引入U型结构的方法,实现其宽频带宽阻带的性能。对滤波器进行仿真、加工与实测,仿真结果与实测结果吻合良好。加工得到的滤波器3 dB带宽为7.1 GHz,低于-20 dB的高频阻带为9.3 GHz,带内回波损耗低于-23.2 dB,实物尺寸为15 mm伊8.5 mm,具有小型化的特点。实测数据表明,提出的滤波器具有良好的性能,在工程领域具有实际的应用价值。     

Compact microstrip lowpass filter using meandered unequal T-shaped resonator with ultra-wide rejection band

In this paper, a compact lowpass filter (LPF) with ultra-wide rejection band has been presented. In fact, a novel meandered semi-hairpin resonator has been used and the stopband characteristics have been improved by using a combinatorial suppressing unit. The suppressing unit contains a combination between T-shaped and semi-circular patches, which are loaded symmetrically to the designed resonator. For the proposed LPF, the-3 dB cut-off frequency has been adjusted to 2.2 GHz. After simulations, the proposed LPF has been fabricated and tested. The experimental results validated that the rejection bandwidth is expanded from 2.471 GHz to 28.62 GHz with corresponding attenuation level of −20 dB. The transition band is only 0.271 GHz from 2.2 GHz to 2.471 GHz with corresponding attenuation levels of −3 dB to −20 dB, respectively. In addition, the measured maximum insertion loss and return loss in the passband, from DC to 2.04 GHz (93% of the passband region) are 0.2 dB and 17 dB, respectively.     

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。     

一种具有陡峭边带的宽带带通滤波器设计

基于一种新型的多模谐振器设计了一款宽带带通滤波器,该多模谐振器由鱼骨形谐振器及中心加载倒T形谐振器构成。滤波器的中心频率位于2.47 GHz,相对带宽为100%。滤波器具有极高的频率选择性,其边带滚降速度分别为232 dB/GHz和168 dB/GHz。此外,滤波器还具有较低插入损耗0.4 dB,紧凑的电路尺寸以及宽阻带抑制能力。     

Optimisation of SIW bandpass filter with wide and sharp stopband using space mapping

This work presents a substrate integrated waveguide (SIW) bandpass filter with wide and precipitous stopband, which is different from filters with a direct input/output coupling structure. Higher modes in the SIW cavities are used to generate the finite transmission zeros for improved stopband performance. The design of SIW filters requires full wave electromagnetic simulation and extensive optimisation. If a full wave solver is used for optimisation, the design process is very time consuming. The space mapping (SM) approach has been called upon to alleviate this problem. In this case, the coarse model is optimised using an equivalent circuit model-based representation of the structure for fast computations. On the other hand, the verification of the design is completed with an accurate fine model full wave simulation. A fourth-order filter with a passband of 12.0–12.5 GHz is fabricated on a single layer Rogers RT/Duroid 5880 substrate. The return loss is better than 17.4 dB in the passband and the rejection is more than 40 dB in the stopband. The stopband is from 2 to 11 GHz and 13.5 to 17.3 GHz, demonstrating a wide bandwidth performance.     

Compact wideband bandpass filter using quad mode resonator

This paper presents a compact wideband bandpass filter for TETRA band applications. The proposed filter design is based on a quad mode resonator designed using small rectangular loop loaded with four Stepped Impedance Stubs (SISs) and a short circuit stub. The four modes of the resonator help in generating a wide passband. The use of SISs makes the filter compact. In addition to four transmission poles, the resonator inherently generates a transmission zero above the higher end of passband. Two transmission zeros are generated by the input/output coupling which helps in increasing the selectivity and also for achieving wide stopband. This filter provides a 3 dB fractional bandwidth of 30.33% and maximum insertion loss of 1.3 dB at the center frequency 0.36 GHz with a compact size of 0.125 λ_g × 0.085 λg (4.1 × 2.78 cm²).     

基于谐振器慢波传输线的小型化宽阻带谐波抑制功分器

该文提出一种基于谐振器慢波传输线的小型化宽阻带谐波抑制功分器,该谐振器慢波传输线由矩形谐振器、T型谐振器和蛇形线构成,来取代功分器中的1/4波长传统微带传输线。所设计制作的功分器,其尺寸仅为传统微带功分器的37.4%。实验结果表明,该功分器回波损耗大于10 dB的带宽范围为0.1～1.19 GHz,在2.2～11.05 GHz频率范围内衰减大于20 dB,具有较宽的阻带从而具有抑制谐波效果。仿真和测试结果较为吻合,验证了所提设计方法的有效性。     

60-GHz Band Dual-Mode Microstrip Ring Resonator Bandpass Filter Using Micromachining Technology

A new compact millimeter-wave dual-mode ring resonator bandpass filter is proposed. This filter has a 15% bandwidth at 58 GHz with 3.4 dB insertion loss. Input/output lines and ring resonator are directly connected to obtain tight coupling, and an open-end stub is inserted for dual-mode operation. This filter is fabricated on a GaAs wafer by using MEMS technology and can be applied for the millimeter- wave SoC.     

A New Approach to the Realization of a Dual-Band Microstrip Filter With Very Wide Upper Stopband

This paper presents the design of a new dual-band filter with very wide upper stopband. The proposed circuit offers a simple and compact structure with low insertion loss. Spurious suppression is achieved by using specially designed coupling and resonator sections. Moreover, a systematic analysis is applied to the proposed topology with closed-form design equations derived. For verification purposes, the measured performance of a microstrip filter operating at 1 and 2 GHz is shown with stopband attenuation of greater than 20 dB over the frequency range from 2.5 to 8.0 GHz.     

Compact and wideband microstrip bandstop filter

A novel one-section bandstop filter (BSF), which possesses the characteristics of compact size, wide bandwidth, and low insertion loss is proposed and fabricated. This bandstop filter was constructed by using single quarter-wavelength resonator with one section of anti-coupled lines with short circuits at one end. The attenuation-pole characteristics of this type of bandstop filters are investigated through TEM transmission-line model. Design procedures are clearly presented. The 3-dB bandwidth of the first stopband and insertion loss of the first passband of this BSF is from 2.3 GHz to 9.5 GHz and below 0.3 dB, respectively. There is good agreement between the simulated and experimental results.