应用交指电容加载环谐振器的微带带阻滤波器

提出了一种交指电容加载环谐振器(IDCLLR),与同尺寸的开环谐振器(SRR)相比,具有更多的设计参数、更低的谐振频率和更大的动态范围,因而使得设计更加灵活、也更适于器件小型化.随后提出两种基于IDCLLR的亚波长微带带阻滤波器结构:第一种是由一对IDCLLR磁耦合到50欧姆微带传输线构成的滤波器,获得0.39%(-10 dB)的窄的阻带;第二种是由一个IDCLLR磁耦合到U形微带传输线中构成的滤波器,由于增强耦合而获得2.4%的较宽且深的阻带.文中给出了它们的全波仿真和测试结果.     

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.     

基于平衡技术的微带低通滤波器版图优化设计

微带线结构的不连续性,使反射损耗和插入损耗较大,影响滤波器性能。利用平衡法提升滤波器并联分支中较低的特性阻抗,达到降低微带线宽度的目的,从而均衡整个滤波器的宽度,使版图仿真优化。以一个5阶切比雪夫微带低通滤波器设计为例,仿真结果表明,滤波器通带内反射损耗从-9.566dB降低到-15.837dB,插入损耗从0.679dB降低到0.322dB,与直接采用Richards变换和Kuroda规则设计微带低通滤波器相比,该方法能缩短滤波器设计周期,获得满意的滤波器性能。     

T形贴片双模微带带通滤波器

基于传统的T形贴片双模微带带通滤波器,提出了一种新型的加入缝隙耦合的T形双模微带带通滤波器。在T形贴片谐振器的两侧以缝隙耦合的方式插入馈线,并对其进行了优化。优化后的滤波器能在通带两侧都产生衰减极点,提高了阻带的抑制能力,对其进行了仿真。仿真结果表明,该滤波器通带的中心频率为5.0 GHz,与实测结果基本一致,滤波器尺寸为34 mm×24 mm,保证了滤波器的小型化。     

Multi-mode multi-band bandpass filter using hexagonal patch resonator

Resonant performances of the hexagonal resonators are analysed, and new tri-mode tri-band bandpass filter which operates at 2.5/2.8, 5.2/5.5 and 7.9/8.5 GHz with insertion loss of no more than 1.3 dB is presented by using a single fractal hexagonal resonator. It shows with fractal-shaped defection in hexagonal patch, filter performance is greatly improved and dual and tri-band bandpass filters can be implemented. The tri-band designs are demonstrated by experiment. The new hexagonal filter has outstanding advantages of multiple-band operation, miniature size, simple and compact structure without resonator coupling gaps. All these features are quite useful for applications in RF circuits.     

圆形开槽贴片微带双模带通滤波器

提出了一种新颖、简单的圆形贴片上刻蚀小方槽的微带双模带通滤波器结构.该滤波器仿真的通带中心频率为5.9 GHz,最大回波损耗优于-31.5 dB,通带内最小插入损耗为- 0.7 dB,3 dB带宽为23.73％.实测和仿真结果相一致.     

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.     

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。     

Miniaturized microstrip bandpass filter designed using rectangular dual spiral resonator

A miniaturized microstrip bandpass filter based on a rectangular dual spiral resonator (DSR) is proposed in this paper. The rectangular DSR bandpass filter is centered at 3.65 GHz to suit for Wireless LAN (IEEE802.11y) application. The proposed filter offers transmission zero at the high side of out-of-band response. Across the bandwidth, the measured minimum insertion loss is about 1.7 dB, while the measured return loss is better than 19 dB. Measurement results are good agreement and closed to the simulated ones. The total circuit size of the miniaturized bandpass filter is about 0.145λ_g by 0.135λ_g, where λ_g is the guided wavelength at 3.65 GHz.     

小型化超宽阻带共面波导低通滤波器设计

为了解决传统CPW低通滤波器尺寸偏大、阻带较窄和插入损耗偏大的问题,采用 /4阶梯阻抗谐振单元（SIR）加载半圆形并联枝节（SISS）和缺陷地结构（DGS）单元的紧凑型结构设计了一个5阶CPW低通滤波器,分析了各单元结构参数对阻带性能的影响,引入微带线补偿方法对共面波导中心导体线特性阻抗进行局部补偿,改善了阻抗匹配性能,进一步降低了通带内的回波损耗和插入损耗。测试结果表明：该滤波器结构尺寸25mm×18mm,3dB截止频率3.5GHz,阻带范围3.8～17GHz。实现了CPW低通滤波器的低插入损耗、超宽阻带和小型化。     

Design of Bessel low-pass filter using DGS for RF/microwave applications

A synthesis method to design a defected ground structures (DGS)-based Bessel low-pass filter (LPF) using a triangular and an open-square (OS)-type DGS is reported. For the five-pole Bessel LPF at f_c = 2.5 GHz, we get 10.6 dB/GHz selectivity using the triangular DGS; while the OS-type DGS provides 39 dB/GHz selectivity. For these two filters, the 10 dB impedance matching BW is 76% and 84%, respectively. It is a much wider BW that is obtained for a lumped element Bessel LPF. The maximum group delay (GD) variation within the pass band is 25pS and 28pS, respectively. The 20 dB rejection BW can be increased from 5.8 GHz to 18.8 GHz with increase in the order of filter from 5 to 11. We have also presented the design of a compact five-pole DGS-based elliptic filter with selectivity 38.2 dB/GHz and 17.8 dB return loss. Results on the DGS-based elliptic filter, Butterworth and Chebyshev filters are also presented. The experimental results are compared against the recently reported LPFs. Our reported filters perform better with respect to selectivity and group delay variation. The flatter GD and high selectivity, along with a wide 10 dB impedance matching BW, make the DGS Bessel filter a candidate for high-speed data communication, front end of a wideband communication system and efficiency improvement of a power amplifier.     

新型折叠多模微带带通滤波器设计

文中提出了一种新型的小型化微带带通滤波器设计方案.方案所提微带带通滤波器的基本结构是折叠多模谐振器,该谐振器不仅具有谐振元件的特性,还能作为开路短截线.新型微带带通滤波器能够实现宽频带的通带响应,并在通带内具有较低的插入损耗和良好的阻带匹配特性,且在通带外额外产生了一对传输零点.本文给出了滤波器的等效电路分析和初步设计方案.该滤波器的最大优点在于进一步减小了滤波器尺寸,同时改善了滤波器的衰减极点,其中心频率为5.2 GHz.     

一种超宽阻带微带低通滤波器的设计

基于传统阶跃阻抗滤波器,提出了一种易于实现的超宽阻带微带低通滤波器改进设计方案。低阻抗线部分采用扇形微带结构,在同等阶数下,该结构的滤波器与传统阶跃阻抗滤波器相比,具有更紧凑的电路结构以及更好的阻带特性。在滤波器末端并联开路短截线,使得阻带增加额外传输陷波点来抑制寄生通带。利用ADS和HFSS仿真软件对滤波器结构进行优化设计,并进行了实物的加工和测试。实测结果表明,通带3 dB 截止频率为2 GHz,通带内0-1.8 GHz 回波损耗大于20 dB,3-20 GHz 频率范围内的阻带抑制能达到25 dB 以上。     

Compact microstrip low pass filter with flat group-delay using triangle-shaped resonators

In this paper, a compact microstrip lowpass filter (LPF) using triangle-shaped resonators is presented. The designed LPF includes three symmetric triangle-shaped resonators to provide a suitable passband and sharp response. A suppressing unit composed of several suppressing cells is designed to obtain a wide rejection band and low insertion loss in the passband. The fabricated LPF has been measured and indicts that it has −3 dB cut off frequency at 5.15 GHz. The rejection band has been expended from 5.51 GHz to 43.2 GHz with maximally flat return loss in this region nearby to 0 dB. Also, simulation and experimental results show that the proposed filter has a very flat group delay in the passband, which is the minimum value in comparison with the published works since 2017.     

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.     

Microwave permittivity of leaf using an Ag thick-film microstrip resonator

The X-band microwave dielectric constant, dielectric loss and the conductivity of the leaves of four different plants were measured from even and odd mode resonance characteristics of an Ag thick-film microstrip straight resonator, due to the perturbation caused by leafy vegetation as an overlay. Using the changes in the frequency response, the moisture-dependent X-band microwave properties of the leaves of Ficus Bengalensis, Ficus Religiosa, Acalypha Wilkensiana, and Acalypha Hispidia have been calculated. The permittivity obtained depends on the position of the overlay and moisture content. A partial overlay method might be a low-cost alternative for dielectric characterisation of biomaterials since a very small size of leaf is needed.     

New compact low-pass filter (LPF) using cascaded square open loop resonator

This article introduces a new design technique of low-pass filter using cascaded square open loop resonator (SOLR) for the multi-wireless communication system. In the design procedure, a half-wavelength SOLR is realized with 6 GHz to meet the desired LPF cut off frequency. As the resonator is fed by a direct connection of 50-ohm input/output ports, the structure is directly transferred into a second-order low-pass filter with elliptic behavior. An equivalent circuit is extracted and its lumped elements are computed to support the proposed second-order LPF. Based on the equivalent circuit, highly selective third and fifth-order LPFs with wide rejection band are developed. To achieve this development several SOLR are cascaded by a direct connection. The designed filters are implemented on a grounded substrate which has relative permittivity of 6.15 and thickness of 0.508 mm. To verify the design concept, a third-order LPF using two cascaded SOLRs is designed, simulated, fabricated and measured. The filter responses obtained from theory, simulation, and measurement show good agreement. The filter has very small circuit area about 31 mm² excluding the input/output feeding ports.     

新型的方形贴片双模微带带通滤波器

提出了一种新型的方形贴片双模微带带通滤波器。该滤波器结构有一个切角,并且在贴片中心处开了一个两臂等长的十字槽,采用正交直接馈电方式,并在每条馈线上引入了一节与谐振腔有一定耦合的开路短截线。该结构在上下阻带都产生衰减极点,馈线上引入的微带线有效地抑制了寄生通带,提高了阻带抑制特性。仿真结果表明,该滤波器在中心频率2.9 GHz处,回波损耗优于–30.9 dB,通带内最小插入损耗为–0.1 dB,与实测结果基本一致。     

基于人工电磁材料的微带贴片天线频带展宽

提出一种以人工电磁材料作为介质基板的矩形微带贴片天线。通过改变人工电磁材料各单元的几何尺寸来控制介质基板的参数变化,以构成非均匀介质基板,使得贴片辐射边的辐射性能提高,从而有效提高了带宽。对设计的非均匀介质微带天线使用HFSS软件仿真。结果表明,普通均匀介质微带天线电压驻波比VSWR≤2时带宽只有0.5GHz,相对带宽为6.7%,而以人工电磁材料为非均匀介质基板的微带天线VSWR≤2时带宽达到1.6GHz,相对带宽达到20.0%。