基于方环型频率选择表面的小型化设计

 为解决频率选择表面（frequency selective surface, FSS）在工程应用中的尺寸限制问题,提出了一种新型小型化FSS. 新结构通过增大方环谐振单元的等效电容和等效电感实现频率选择表面的小型化,与前人提出的小型化FSS比较,该新型FSS单元的尺寸更小,仅为0.079λ₀×0.079λ₀（λ₀为阻带中心频率点对应的波长）.另外,新结构的高度对称性确保了其性能的高稳定性,仿真和实测结果表明：新结构对不同角度和不同模式的入射波保持了十分稳定的传输特性．     

基于EBG结构的基片集成波导超宽带带通滤波器

为拓展带通滤波器的通带带宽,设计了一种基于EBG结构的基片集成波导（SIW）超宽带带通滤波器．该滤波器利用箭头形电磁带隙结构的阻波特性,将不同大小箭头形结构单元蚀刻在SIW上金属面,以获得超宽带通带．所设计的滤波器中心频率在985 GHz,相对带宽为3959%,通带内的最大插入损耗约为154 dB,相比于类似结构的带通滤波器,其带内回波损耗较大,且整体电路面积较小．测量结果与仿真结果基本吻合,有效地验证了该设计方法的有效性．     

基于H型超材料的小型化调频空间滤波器

基于超材料的相位补偿特性实现特定波段超材料滤波器设计。本工作通过变形传统的互补型开口谐振环,设计了一种小型化哑铃型缝隙结构超材料滤波器,通过二极管控制超材料的电磁特性在不同时间的空间分布形式,以实现空间滤波器中心频率可调。滤波器单元尺寸为5.0 mm×5.0 mm×0.8 mm,具有小型化的特点。仿真结果表明:-10 dB工作带宽为28%(9.2～12 GHz),回波损耗最小值为29 dB,插入损耗最大值为0.8 dB。测试结果表明:-10 dB工作带宽为25%(9.2～11.7 GHz),回波损耗最小值为20 dB,插入损耗最大值为1.0 dB。     

一种准光带阻滤波器的仿真与实验研究

对中心频率为225GHz的谐振环结构(SRR)带阻滤波器进行了仿真分析和实验研究。采用HFSS仿真模拟技术,研究了SRR开口宽度、线宽、加载介质以及极化角度等相关参量对其谐振特性的影响。结果表明,该带阻滤波器的频率响应特性对场极化角度的敏感性很低,具有较好的稳定性;实验中测试到样品的中心频率为225.6GHz,与仿真结果有一定的偏差。通过进一步分析发现,影响频率偏移的主要因素是样品的实际尺寸偏小和介质的介电常数偏大,导致实际测试响应频率小于设计值。     

一种新型小型化交叉耦合带通滤波器的设计

本文设计了一种基于阶跃阻抗谐振器的新型嵌入式交叉耦合带通滤波器.为使滤波器小型化,设计了两种紧凑型阶跃阻抗谐振器结构.通过研究和改善谐振器间的耦合机制,可使两种谐振器不仅形成嵌入式结构,而且缩减了馈线占据的面积,进一步减小了含馈线在内整个带通滤波器的尺寸.为验证此方法的可行性,利用滤波器综合法设计了一个中心频率为2.4GHz,相对带宽FBW为15%的4阶交叉耦合带通滤波器,其最终设计尺寸为28mm×20mm(0.37λ_g×0.26λ_g,λ_g为中心频率所对应的导波波长).对该滤波器进行了仿真、加工和测试,结果表明该滤波器具有所需的广义切比雪夫特性,且互相吻合得很好.     

一种基于SIFW的小型化宽带带通滤波器

为实现射频系统的小型化,本文设计出一种基于基片集成折叠波导( Substrate integrated folded waveguide,简称SIFW)的小型化宽带带通滤波器,并给出了仿真结果.为了改善带外抑制,滤波器通过交叉耦合,在通带低端引入两个传输零点.为改善通带高端滤波特性,在顶层和底层金属微带上刻蚀互补型开口谐振环(Complementary Split Ring Resonators,简称CSRR).仿真结果表明,所实现的滤波器中心频率在7.1 GHz,相对带宽约为47％,通带内回波损耗优于-15dB,插入损耗小于0.7dB.     

一种基于LTCC的小型化吸收式带通滤波器的设计

提出了一种基于LTCC技术的新型小型化吸收式带通滤波器的实现方法。该吸收式滤波器基于耦合相消原理由两个四阶梳状线带通滤波器和两个3dB正交定向耦合器组成。为了减小实物体积,梳状线带通滤波器采用三层短路耦合线结构,耦合器采用两层蛇形宽边耦合带状线结构,并且上下放置两个梳状线带通滤波器。运用三维电磁仿真软件HFSS建模仿真,设计了一款吸收频带范围为2GHz～4GHz,滤波频带范围为2.85GHz～3.25GHz的吸收式带通滤波器,通带内插入损耗小于2dB,各端口驻波比优于1.4,在低阻带0GHz～2.55GHz和高阻带3.55GHz～5GHz内的衰减均大于30dB,体积仅为8.4mm×5mm×2.5mm。测试结果与HFSS仿真结果较为吻合。     

集总参数滤波器的设计

首先介绍集总参数滤波器的设计方法,设计一个集总参数带通滤波器,中心频率为200MHz,带宽20MHz,两个端口的特征阻抗为50Ω,带内插入损耗<3dB,带内波纹<0.5dB,在f<190MHz和f>210MHz处阻带衰减>15dB,利用ADS软件进行仿真和优化。     

类椭圆型虹膜波导带阻滤波器设计

为构建类椭圆型滤波器所需的传输零点,基于虹膜嵌入波导结构设计了一款虹膜波导带阻滤波器。研究表明,通过调节虹膜窗口尺寸可实现传输零点频率位置的精确可控;虹膜厚度与工作频率成正比,厚度由1mm增加到2mm,中心频率上移约3%;虹膜嵌入位置与工作频率无关,仅对下频带谐振响应造成少量延迟。该滤波器中心频率79.2GHz,阻带抑制大于40dB,长度尺寸小于1cm。多个独立调控虹膜嵌入波导的设计方法可构建阻带所需的多衰减极点,设计方案可应用于超高容量通信系统。     

G形DMS结构高选择性低通滤波器的分析与设计

提出一种新颖的G形缺陷微带结构(DMS)微带线,以G形DMS为结构单元,设计并实现了一种具有高选择性和宽阻带特性的微带低通滤波器.与传统的DMS结构相比,G形DMS具有更低的谐振频率和更宽的阻带抑制.对设计的滤波器进行了测试,实测结果表明:该滤波器3dB截止频率为3.17GHz,频率选择性达189dB/GHz,同时在3.4GHz ～ 10GHz阻带内抑制度大于25dB,有效地抑制了二次和三次谐波.该滤波器占用大小仅为26mm×15mm,实测结果与仿真良好吻合,表明了该DMS的有效性及实用性.     

Study and realisation of dual-composite right/left-handed coplanar waveguide metamaterial in MMIC technology

A novel realisable dual composite right/left-handed (D-CRLH) coplanar waveguide (CPW) transmission line (TL) in GaAs MMIC technology demonstrated by theoretical analysis and experimental results is presented. A D-CRLH TL is the dual of the conventional CRLH TL in the sense that it consists of series LC parallel tanks and shunt LC series tanks. However, an ideal D-CRLH TL cannot be realised because of unavoidable parasitic effects. The measured results indicated that a real D-CRLH TL exhibits a fundamentally different frequency response at higher frequency band in that a real D-CRLH TL cannot provide unlimited left handed (LH) bandwidth. Instead, it has triple bands; right-handed (RH) passband at lower frequencies (DC-2.9 GHz), LH passband at intermediate frequencies (5.1 14.3 GHz) and RH passband at higher frequencies (above 14.3 GHz). The reported fully integrated D-CRLH CPW TL metamaterial has a very compact size of 2.2 mm² which leads to a small loss 1.5 dB within 3 dB LH passband.     

Left-handed L-band notch bandstop filter with significantly reduced size

An innovative compact microstrip line left-handed (LH) L-band notch bandstop filter is presented, validated by full-wave simulations and demonstrated by experiments, showing that the size of the filter can be significantly reduced by employing the LH transmission line (TL) metamaterials. The proposed notch bandstop filter was constructed using coupled line coupler loaded with 90deg LH TL. The size of the fabricated LH filter is 4.4 times smaller than that of the filter loaded with -270deg conventional TL and nearly two times smaller than that of the filter loaded with -270deg meandered TL. The filter has a centre frequency of 1.164 GHz and a fractional bandwidth of 0.51%. The loaded quality factor of the filter is 197, indicating 64 and 97% increases in comparison with the conventional and meandered TL filters, respectively     

Novel compact microstrip interdigital bandstop filters

A novel compact microstrip interdigital band-stop filter is designed and implemented. The structure is similar to that of an interdigital capacitor. The input port and output ports are connected to form the bandstop characteristic. This proposed filter with microstrip interdigital geometry not only exhibits good bandstop characteristics and a tunable central frequency, but it also is easy to fabricate and integrate. The features of this microstrip interdigital bandstop filter are smaller than those of the conventional bandstop filter. Simulation results closely correspond to the experiments.     

Tunable slotted ground structured bandstop filter with BST varactors

This paper presents an investigation of a tunable bandstop filter (BSF) using slotted ground structure. A kind of open loop slot resonator is used for the bandstop response and its characteristics according to various dimensions are considered to decide a proper shape for the final design. A barium-strontium-titanate (BST) varactor chip is deployed to tune each resonator and its location is determined by electromagnetic simulation for an optimum frequency tuning. A three-pole tunable BSF of this type is measured at the centre frequency from 4.5 to 5.5 GHz and its rejection is more than 20 dB at the stop band while the insertion loss at the pass band is less than 1.5 dB.     

Ultra-wideband bandpass filters with improved out-of-band behaviour via embedded electromagnetic-bandgap

A class of ultra-wideband microstrip-line bandpass filters with improved out-of-band behaviours is presented by using an electromagnetic (EM) bandgap embedded multimode resonator. At first, the two EM bandgap structures are constructed by periodically loading uniform or non-uniform open-circuited stubs. Their performances are numerically characterised, aiming at exhibiting the existence of a bandstop in a frequency range of 15.0?30.0 GHz. These bandgap structures are then internally embedded in the middle part of an open-ended microstrip line resonator, constituting a modified type of multimode resonator. In the design, the dimensions of this resonator need to be properly adjusted towards allocating the first three resonant modes in the 3.1?10.6 GHz ultra-wide passband. To achieve a preferably wide upper stopband, the transmission zero of parallel-coupled lines is used to cancel the spurious fourth-order resonant mode. Also, higher-order modes in the upper band are inhibited by the employed bandgap structures. Two bandpass filters using the nonuniform stub-loaded resonator are finally designed, fabricated and tested. Predicted insertion/return losses and group delays are experimentally confirmed in a wide frequency range of 1.0?30.0 GHz.     

新型半模基片集成波导漏波天线

 为了设计一种结构简单、可靠性高的全向天线,提出了一种基于半模基片集成波导技术的漏波天线.这种天线是在半模基片集成波导结构的H壁增加4个对称振子形成的漏波辐射结构.使用电磁仿真软件对提出的天线结构进行了精确的建模,分析了介质厚度对天线带宽的影响,并对天线结构进行了优化,最后制作了天线测试样片进行实验验证.所设计的天线具有较宽的带宽和准全向辐射的特性,在7.3~9.7 GHz频段内具有良好的辐射性能,最大增益为5.8 dBi,测试结果验证了设计的有效性．     

Varactor-tuned quarter-wavelength dual-bandpass filter

A tunable dual-band bandpass microstrip filter is proposed and presented. It is composed of two pairs of quarter-wavelength transmission line resonators and two bandstop structures made of open stubs. Each operation bandpass frequency, denoted by f/sub 1/and f/sub 2/, is generated by a pair of coupled resonators. The first coupled resonator is fed via a tap-coupled structure, while the second is fed through a coupling structure. The tunability of each bandpass and harmonic suppression is achieved by modifying the electrical length of the resonators and the electrical length of the open stubs by using varactor-diode capacitors. Finally, a 2.5 and 4.25 GHz dual band bandpass filter is designed, fabricated and measured as one example and a tunability of 22.2% and 19.6%, respectively, is obtained for the first and second bands. These excellent experimental results validate the proposed structure and design technique for dual-band bandpass filters.     

基于新型H形DGS超宽带低通滤波器设计

滤波器是微波电路的重要元件,在实际中有着广泛的应用.对传统的H形缺陷地面结构进行了改进,提出了新型的H形缺陷地面结构(H-shaped DGS),研究了新结构的传输特性,利用所提出的新型结构设计了一个超宽带低通滤波器,并对其进行仿真与测试,仿真结果与实验结果吻合较好.测试结果表明:所设计的低通滤波器的3dB通带截止频率...     

一种SETMOS二阶带通滤波器设计实现

单电子晶体管（SET）作为一种纳电子器件有着较大的优势,将SET与纳米MOS混合构成的器件（SETMOS）是目前研究的热点之一。SETMOS作为一种新的混合器件,在结合了两者优点的同时,具有与SET一样的库仑振荡特性和MOS高增益等特性。文章基于一种sETM0s混合结构的电压电流特性的数学模型,设计并实现了一种SETMOS二阶带通滤波器,阐述了这种SETMOS带通滤波器的结构、工作条件、性能、参数和特点,并用PSpice对其传输特性进行了仿真验证,结果证明,SETMOS在其通带范围内具有良好的带通幅频特性,且具有低电压、低功耗和高频的特点。