A compact dual-band bandpass filter based on porous silicon dual-microcavity of one-dimensional photonic crystal

We demonstrate a laser-diode(LD)pumped actively Q-switched laser with Nd:Sc0.2Y0.8Si O5(Nd:SYSO)crystal for the first time.A stable actively Q-switched laser is obtained at dual wavelengths of 1 075.2 nm and 1 078.2 nm.The maximum average output power of 720 m W is obtained at the repetition rate of 15 k Hz under the pump power of8.7 W.The minimum pulse width of 58 ns is obtained at the repetition rate of 5 k Hz under the pump power of 8.7 W,corresponding to the peak power of 1.9 k W and the pulse energy of 112μJ.     

A new compact LTCC bandpass filter using negative coupling

This letter presents the design and realization of a new compact bandpass filter (BPF) fabricated on multilayered ceramic substrates. This BPF features coupled resonators with negative coupling coefficients. A BPF with center frequency 2.45 GHz is designed and fabricated. Its size is only 2.0 mm/spl times/1.8 mm/spl times/0.67 mm when implemented by a standard low temperature co-fired ceramic technology. The size reduction is due to the higher coupling coefficient between the negatively-coupled resonators than the positively-coupled ones, allowing tighter space between the resonators. The measured insertion losses of the previous BPF were less than 3dB and return losses more than 18dB in the passband. The measured result agrees very well with the electromagnetic (EM) designed response.     

Design of compact dual-band switchable bandpass filter

A compact dual-band switchable bandpass filter is designed using two centrally-loaded open-loop resonators and six pin blocks. The pin diodes are loaded at the zero-voltage points of odd and even modes along the microstrip resonators, such that the two passbands operating at odd and even modes can be individually switched on or off. The isolations for the two passbands are greater than 20 dB.     

A new LC series element for compact bandpass filter design

A new LC series element based on a modified version of the split rings resonator introduced in is proposed. Owing to its small electrical size, the new open split ring resonator (OSRR) is a very attractive element for compact bandpass filter design. As an example, we have designed and fabricated a filter to produce a bandpass around the resonance frequency of the employed OSRRs. The filter bandwidth is controlled by the length of the transmission lines connecting the OSRRs. Sharp and deep out-of-band rejection is achieved by cascading several OSRRs. Circuit theory and electromagnetic based simulations reasonably agree with experiments.     

Improved and compact 0.7 GHz tune-all bandpass filter

A compact tune-all bandpass filter is presented. This electronically tuned filter is based on series-coupled slow-wave resonators. It allows wide simultaneous and continuous tunings of centre frequency (+/-15% around 0.7 GHz) and bandwidth (from 50 to 100 MHz) with insertion loss IL<5.4 dB and return loss RL>11 dB. This two-pole bandpass filter exhibits also a very small surface of only 7.3times10^-3 lambda₀ ² and a -20 dB stop-band that extends up to 10 GHz     

一种基于SIR结构的三通带带通滤波器

应用双指耦合结构和枝节加载谐振器（Stub-loaded Resonator,SLR）实现了一款基于阶梯阻抗谐振器（Stepped Impedance Resonator,SIR）的滤波器。该滤波器具有3个通带,带外抑制较好,工作频段提高。通过调整阻抗比可调节第二、三通带的谐振频率;SLR结构能够增加通带数量;SLR结构和双指耦合结构均能改善滤波器的S参数。HFSS软件仿真表明,3个通带的中心频率分别为3.5 GHz、6.6 GHz、9.2 GHz,对应的分数带宽分别为5.7%、3%、2%,S11分别为-18 dB、-22 dB、-24 dB,通带内的S21分别为-1.8 dB、-1 dB、-1 dB。电路的测量结果与仿真结果较为吻合。该滤波器在5G通信的低频段具有应用前景。     

New compact wideband bandpass filter using three parallel-coupledlines

A new miniature bandpass filter, comprising three-conductor short-circuited spurline resonators of approximately a quarter-wavelength long, with a very wide bandwidth approaching multioctaves is reported for the first time. The chain matrix of the filter resonator is derived. The new filter has been developed using microstrip line with less than 1 dB insertion loss over a passband from 2 to 8 GHz. Reasonably good agreement between the measured and calculated results is observed     

采用新型介质集成波导腔的小型双频滤波器

提出了一种新式的横电磁波-基片集成波导(TEM-SIW)谐振腔。这种TEM-SIW谐振腔由经典的基片集成波导(SIW)腔发展而来。通过在SIW腔的中心位置加入短路销钉,将SIW腔体的上金属平面与腔四周导体壁开路构成TEM-SIW腔。相同谐振频率下,单个TEM-SIW腔的面积可以减小到传统的SIW谐振腔面积的9.5%。分析了主模式工作情况下TEM-SIW谐振腔和传统的SIW谐振腔的结构以及腔内的磁场分布。由于其磁场分布与工作在TEM模式的电容加载同轴腔相似,因此,基于这种谐振腔的滤波器可以很方便的借鉴经典的电容加载同轴腔滤波器的耦合结构和综合设计技术。最后,设计了一个基于TEM-SIW腔的三级双频滤波器,其性能已经通过了数值仿真和实验验证。     

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.     

40 GHz compact TFMS meander-line bandpass filter on silicon substrate

Presented is a compact millimetre-wave bandpass filter using a thin-film microstrip meander line on standard 0.18 mum CMOS silicon substrate without any post-processing step yet still reducing the substrate loss and crosstalk to a large extent. To miniaturize overall circuit size, a half-wavelength resonator is constructed in meander-line configuration and its resonant frequency is designed to be 40 GHz. The prototype single-resonator bandpass filter occupies a circuit area of 210 times 210 mum on silicon. Measured insertion loss is 2.5 dB, which agrees well with the design value in the simulations.     

Design of a compact microstrip tunable dual-band bandpass filter

A novel microstrip tunable dual-band bandpass filter with high attenuation level in the upper stopband region is presented. The proposed structure comprises of T-shaped resonators and the coupled microstrip feeding lines. To reach a compact size, the feeding lines are bended. By altering the physical lengths, the characteristics of BPF can easily tune. So, the operational frequencies of the filter can be adjusted and has been fixed to 2.1 GHz and 2.63 GHz, which are applicative for 3G and 4G systems. The insertion-losses of the first and second pass-bands are only 0.68 dB and 1.08 dB, respectively. The undesired harmonics in the upper stopband, with an excellent attenuation level of −38 dB, are rejected up to 6.65 GHz. The results exhibit high return loss of 19.3 dB and 30.7 dB in the first and second pass-bands. The proposed circuit has been fabricated and tested that the obtained results are well close to the simulations results. The total size of the designed circuit is only 16.4 × 13.4 mm².     

基于SISL的介质填充双通带滤波器设计

为实现滤波器的小型化,基于介质集成悬置线(substrate integrated suspended line, SISL)结构提出了一种介质填充双通带滤波器的设计方案. 首先将高介电常数的介质块填充入SISL的空气腔中,提升SISL的等效介电常数,实现电路的小型化,高介电常数介质块可以直接被SISL固定;然后利用T型结连接两组工作在不同频段的滤波器从而使得两个通带相对独立;最后利用仿真软件进行优化,确定介质填充双通带滤波器的尺寸,并进行加工与测试. 仿真与测试结果表明,二者具有较好的一致性,两个通带频率内的回波损耗均优于15 dB,电路的核心尺寸为0.058λ_g×0.139λ_g(λ_g为SISL在第一通带中心频率处的导波波长). 此双通带滤波器具有小尺寸、自封装等优势,且所有层介质基板均采用低成本的FR4板材,降低了制造成本.     

A novel compact interdigital bandpass filter using multilayer cross-coupled folded quarter-wavelength resonators

In this letter, a novel compact cross-coupled interdigital bandpass filter (BPF) is developed. By using multilayer folded quarter-wavelength resonators, the size of the filter is reduced greatly, meanwhile a cross-coupling is introduced to produce transmission zeros and thereby improve the stopband characteristics of the filter. As an example, a four-pole BPF centered at 2.25GHz with a fractional bandwidth of 31% is designed, fabricated, and measured. The simulated and measured results show an excellent agreement.     

60 GHz compact integrated cross-coupled SIR-MH bandpass filter on bulk CMOS

A new 60 GHz fourth-order cross-coupled bandpass filter using a step- impedance-resonator (SIR) miniaturised open-loop resonator and the miniaturised-hairpin (MH) resonator was designed and fabricated on 0.13 mum bulk CMOS. It has 8.5 GHz (58-66.5 GHz) bandwidth, 5.9 dB insertion loss, and better than 10 dB return loss over the whole passband, and exhibits high selectivity and a compact size of 714.9 times 484 mum (0.346 mm ). This filter is the first reported cross-coupled filter above 40 GHz on CMOS.     

一种基于阶跃阻抗波导带通滤波器的设计

利用阶跃阻抗谐振器(SIR)结构设计波导带通滤波器。该方法减小体积,又可以将杂散谐振频率向高端推移,从而增加阻带宽度,使得结构的设计获得很大的自由。最后,利用电磁场仿真软件对结构尺寸进行优化仿真,并实际制作一个中心频率为780 MHz(通带差损小于0.7 dB)的SIR带通滤波器。实测结果和仿真结果吻合良好,达到预计指标参数。该滤波器具有体积小,结构简单易于加工等优点。     

一种基于微带开口环的双通带滤波器设计

文中提出了一种基于微带开口环的双通带滤波器设计,对比了非对称开口环结构与传统对称结构的传输特性,讨论了非对称结构中两端馈线位置,双环耦合间距以及环线宽度对于滤波器性能的影响,然后在此基础上,利用两级级联耦合开口环设计了一个用于接收机中抑制镜像的双通带滤波器,带外抑制度较高。     

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.     

A compact planar ultra-wideband bandpass filter with multiple resonant and defected ground structure

A compact bandpass filter with dumbbell shape Defected Ground Structure (DGS) operating on ultra wide pass band (UWB – 3.1 to 10.6 GHz) is proposed. It is based on hybrid microstrip coplanar waveguide (dual sided metal) structure. A Multiple Resonant Structure (MRS) is constructed using coplanar waveguide (CPW) planar transmission line. The MRS makes the resonance using quarter wavelength and half wavelength open-ended CPW. The equispaced three resonances at lower (3.1 GHz), center (6.85 GHz) and higher edge (10.6 GHz) of the whole Ultra Wide Band is achieved using CPW MRS. To make the band as flat as possible, two more resonances are introduced using quarter wavelength microstrip patches on top of the commonly shared substrate, so the proposed filter becomes a five pole bandpass filter. A dumbbell shaped defected ground structure on either side of CPW MRS improves the return loss almost less than 20 dB over the whole UWB passband. The simulated results of proposed filter show good transmission response within passband and good rejection in out of the band. The simulated and measured results are very close to each other which proves the efficacy of proposed design.     

基于可重构超材料的太赫兹可调带阻滤波器

设计了一种基于可重构超材料的太赫兹三带可调带阻滤波器。该滤波器各单元均由可动部分与固定部分构成,两部分均采用金-硅两层结构,表层金的厚度为0.65 μm,下层硅的厚度为25 μm。可移动部分由电热驱动器进行驱动,最大位移为5 μm。可动部分为两边长不同的矩形环,固定部分为开口环。用时域有限积分方法研究了滤波特性和频率可调机理,并根据表面电流分布情况,建立了等效电路。由表面电流分布可知,前两个阻带中心频率分别由固定部分的低频偶极子和高频偶极子振荡产生,第三个阻带中心频率由可动部分表面的偶极子振荡产生。该可调带阻滤波器在太赫兹通信和频率选择性太赫兹探测领域有重要应用价值。     

A compact and high performance dual-band bandpass filter based on unbalanced composite right/left-handed transmission lines for WLANs applications

In this paper, a novel compact microstrip dual-band (DB) bandpass filter with high selectivity for wireless local area networks applications is proposed. The design procedure is based on unbalanced composite right/left-handed (UCRLH) transmission lines (TLs). The DB features can be achieved by unbalancing the CRLH transmission line. The necessary conditions to obtain a discontinuous transition between the left- and right-handed bands, intended to provide UCRLLH TL, are investigated. The application of this technique to design of compact DB filters is illustrated. The structure of the proposed DB filter is implemented by a series interdigital capacitor located between two microstrip lines that shorted to the ground plane by vias. The vias with microstrip lines acting as a shunt connected inductor while the series capacitor is realized by interdigital capacitor. The design procedure based on a simple equivalent circuit is also introduced. The proposed filter has advantages such as compact size, easy fabrication, high selectivity, low insertion loss, high return loss and, design flexibility. To validate the proposed technique, the proposed DB filter has been fabricated and tested. Good agreement has been found between simulation and measurement results. The total size of the proposed UCRLH DB filter is 0.17 λ_g × 0.048 λ_g, where λ_g is the guided wavelength of the lower pass-band. The size of the proposed DB filter is more compact in comparison with known similar filters.