一种新型超宽带带通滤波器的设计

介绍一种新型的超宽带带通滤波器,研究了微带阶梯阻抗谐振器的阻抗特性,利用该并联结构实现了超宽带带通滤波器的带外传输零点。设计了一款性能较好的宽带带通滤波器,实际测试结果与仿真结果十分吻合,证明了设计方法的正确性。     

超宽带小型化悬置带状线带通滤波器的设计与优化

为适应越来越密集的微波频段信号环境及小型化的发展要求,利用高低通滤波器级联的方式实现带通滤波器的设计与优化,介绍了一个2～18 GHz超宽带带通滤波器,并给出了测试结果。     

基于微波光子学的光载超宽带信号产生和传输技术

光载超宽带技术因兼具超宽带信号大带宽、传输速率高等优点和光纤传输的远距离传输、损耗小等优势而在近年来备受关注。文章提出一种基于微波光子技术产生超宽带(UWB)信号的系统,该方案基于非线性PM-IM转换,产生一阶超宽带信号,然后又用平衡光电探测器(BPD)和光延迟线构建延迟线滤波器对其进行一阶差分,产生了符合美国联邦通信委员会(FCC)掩膜要求的二阶超宽带信号。系统最终产生的二阶超宽带信号的频谱具有大约5.4 GHz的中心频率和4.3 GHz的10 dB带宽。另外,还提出了一种基于直接序列-二进制相移键控调制(DS-BPSK),并使用卷积编码进行信道编码,然后使用啁啾布拉格光栅对信号进行色散补偿的信号处理技术。通过Opti-system软件进行仿真验证,在前向纠错门限为3.8×10^-3时,接收机灵敏度提升了约5.5 dBm,有效降低了误码率,提升了光载超宽带系统的传输性能。     

具有超宽带吸收特性的Ku 波段带通滤波器设计

为解决Ku 波段带通滤波器带外反射信号干扰系统性能的问题,研究了一种具有超宽带无反射特 性的Ku 波段吸收式带通滤波器(Absorptive Bandpass Filter, ABPF)。该滤波器基于超宽带多级威尔金森(Wilkinson) 功分器/ 合成器和超宽带90°移相器,结合传统反射式带通滤波器,利用进入功分器/合成器的两个支路的反 射波的等幅反相特性,使反射波功率被功分器/ 合成器内的隔离电阻吸收来实现ABPF 阻带内的无反射特性。采 用并联加载λ/4 双短路枝节微带线和参考微带线实现超宽带范围内90°左右的移相特性。设计并制作了一款中 心频率为15.2 GHz 的Ku 波段ABPF 实验样品。实测结果表明,该滤波器的3 dB 通带带宽为1.4 GHz,输入端与 输出端的吸收带宽覆盖5~26.5 GHz,实现了优良的超宽带吸收特性。     

一种具有陷波特性的超宽带带通滤波器

采用修改的多模谐振器(MMR)结构,在输入端与输出端开槽形成交叉耦合,实现了一种结构紧凑、频率选择性较高的超宽带(UWB)带通滤波器。修改的多模谐振器能产生5个模式和2个在高低截止频率附近的传输零点,提高了频率选择性。在滤波器的基础上,通过加载谐振器,形成在8.11 GHz处具有陷波特性的超宽带带通滤波器。利用HFSS13.0验证设计原理。仿真结果表明,该超宽带带通滤波器通带为2.61~11.21 GHz,陷波频率为8.11 GHz,能有效抑制X频段(7.91~8.31 GHz)卫星通信系统对超宽带通信系统的影响,适用于超宽带无线通信系统。     

光纤技术产生超宽带脉冲信号仿真研究

采用仿真方法研究在光纤传输过程中产生并分发超宽带脉冲信号.对系统频响特性的数值分析获知频率响应在低频段表现出带通滤波器特性,且中心波长越短,低频带宽越大.仿真12.5 Gbit/s伪随机序列传输特性表明,高斯脉冲通过系统后,时域上脉冲信号接近于FCC(美国联邦通信认证)的超宽带脉冲波形模板,频域上的信号频谱接近于FCC的频谱规范.     

四分之一波长短截线超宽带滤波器的设计

本文简要介绍了短截线超宽带(UWB)滤波器的发展现状,简述了四分之一波长(λg0/4)短路短截线和开路短截线带通滤波器各短截线特性导纳的计算方法.利用matlab语言开发了综合短截线切比雪夫带通滤波器的程序,介绍了该程序的基本思路,提出了利用该程序与现有的微波CAD软件相结合设计切比雪夫超宽带滤波器的方案,该方案的主要特点是设计时间短精度高,从而大大提高了设计效率.最后利用实例加以说明,设计了一个中心频率为6.85GHz,相对带宽为110%的微带线超宽带滤波器.     

脉冲调制系统滤波器设计及应用

介绍了用于脉冲调制系统的LC带通滤波器设计。通过对滤波器响应函数及电路拓扑结构的选取,可实现带内信号线性相位传输,同时实现较高带外幅频抑制度,有效降低窄脉冲调制接收机输出旁瓣电平和提高噪声抑制。就LC滤波器与SAW带通滤波器对旁瓣及杂散抑制效果进行了比较。     

一种具有双陷波特性的超宽带滤波器设计

针对超宽带(Ultru-wideband,UWB)系统易受窄带信号干扰的问题,文中设计了一种新颖的在5.21GHz和7.95GHz具有双陷波特性的UWB带通滤波器。通过引入互补金属开口谐振环(Complementary Sphit-ring Resonator,CSRR)的方法实现了UWB滤波器的双陷波特性,CSRR结构简单、易于加工、容易与微带平面电路集成.利用仿真软件详细讨论了单环CSRR结构的物理尺寸与滤波器传输特性之间的关系。制作了UWB滤波器实物,测试结果与仿真结果吻合较好,证明了所采用方法的有效性和正确性。     

基本电子电路

TN72006050834调制系统中带通滤波器的设计与应用/王少夫(大连海事大学信息工程学院)//微处理机.―2005,26(6).―64～65.该文介绍了调制系统中LC带通滤波器的设计与应用,通过函数的选取,可实现带内信号线性相位传输,同时实现较高的带外幅频抑制度,有效降低窄脉冲调制接收机输出     

基于正向建模的目标超宽带电磁脉冲雷达回波仿真

为了快速获取超宽带（ultra-wideband,UWB）电磁脉冲激励下雷达目标的时域电磁响应,提出了一种基于散射中心正向建模的目标时域回波仿真方法.从目标几何模型出发,利用空间射线分集技术对强散射源进行分离,通过模型参数正向确定方法构建出目标的属性散射中心模型,用以表征目标高频电磁散射特性,并在UWB电磁脉冲激励下进行仿真运算,获得目标时域回波信号.以典型目标SLICY为例,基于正向建模的散射中心模型,快速获取不同UWB电磁脉冲激励下的雷达回波信号,与高频仿真方法得到的一维距离像（high resolution radar profile,HRRP）进行对比分析,吻合良好.由此验证了本文提出的回波仿真方法的有效性,为不同辐射源激励下目标的快速电磁响应研究提供了一种新思路.     

超宽带极窄脉冲设计与产生

超宽带(UWB)技术是以持续时间极短的脉冲作为传输载体进行数据通信的无线新技术。基于BJT雪崩特性,本文采用并行同时触发的工作方式,设计并产生了高重复速率的UWB脉冲电路发生器,极大地减少了时延,缩短了上升时间,提高了脉冲的幅度,并从等效电路法的观点分析计算了脉冲的特性参数,理论结果与实测结果具有较好的一致性。     

脉冲电磁波传输过程中的失真分析

超宽带通信是近几年发展起来的短距离无线通信技术,而无线通信信道特征取决于信号传播的电磁环境。运用频域法研究大地媒质中的脉冲传播和辐射问题,且在此基础上分析脉冲电磁波穿过3层媒质的失真情况,并分析现代建筑物中的混凝土砖墙对信号传播的影响。通过仿真得到超宽带脉冲信号在传输过程中的失真结果,这对遥感及超宽带通信系统的设计意义重大。     

Dual band notched UWB-BPF based on hybrid microstrip-to-CPW transition

The research paper proposes a compact dual notched band ultra-wideband (UWB) bandpass filter (BPF). The basic architecture of the filter is developed using the hybrid microstrip-to-coplanar waveguide (CPW) technology, wherein a short circuited CPW in ground is coupled vertically via the dielectric to the microstrip lines on the top plane. The broadside alignment generates a three pole BPF with dual transmission zeros (TZs) on either passband/stopband edges which leads to minimum insertion loss passband and sharp roll-offs. Later, multiple spirals and split ring resonators (SRRs) are embedded in the CPW of the UWB filter to introduce the dual notches and widen the stopband respectively. The proposed filter is fabricated to justify its measured response. The proposed filter measures only 14.6 × 7.3 mm².     

Asymmetric dual-line coupling strip for multiple notched bands: Theory and implementation

An asymmetric dual-line coupling strip (ADLCS) can provide main two paths for the signals, which make it possible to generate multiple transmission zeroes. The detailed analysis of the ADLCS is proposed in this paper. Based on the microwave network theory, the equivalent circuit of the ADLCS is also developed. Moreover, the structural parameters of ADLCS are studied by calculations and simulations. The center frequencies and bandwidths of the notch bands can be controlled by tuning the structural parameters. Obviously, The ADLCS can be used in the ultra-wideband (UWB) bandpass filter (BPF) to generate multiple notch bands within the passband. To demonstrate the performance of the ADLCS with UWB filter, the structure is applied to the input and output (I/O) of the single-stage UWB Y-shaped BPFs. The proposed UWB Y-shaped BPF has been designed, fabricated, and measured. The measured results agree with the predicted ones closely. The two notch bands of the fabricated UWB Y-shaped BPF centered at 4.5 and 8.1 GHz have 10-dB rejection fractional bandwidths of about 5.6% and 5%, respectively.     

Triple band notched mushroom and uniplanar EBG structures based UWB MIMO/Diversity antenna with enhanced wide band isolation

Triple band-rejection MIMO/Diversity UWB antenna characteristics are described in this paper. Proposed antenna discards worldwide interoperability for microwave access WiMAX band from 3.3 to 3.6 GHz, wireless local area network WLAN band from 5 to 6 GHz and X-Band satellite downlink communication band from 7.1 to 7.9 GHz. Mushroom Electromagnetic Band Gap (EBG) structures helps to attain band notches in WiMAX and WLAN bands. Uniplanar plus shaped EBG structure is used for notch in X-band downlink satellite communication band. Decoupling strips and slotted ground plane are employed to develop the isolation among two closely spaced UWB monopoles. The individual monopoles are 90° angularly separated with stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing current path length. Mutual coupling magnitude of more than 15 dB is found over whole UWB frequency range. The Envelope Correlation Coefficient is less than 0.02 over whole UWB frequency range.The variations in the notched frequency with the variations in mushroom EBG structure parameters are investigated.The antenna has been designed using FR-4 substrate and overall dimensions is (64 × 45 × 1.6) mm³.     

Electromagnetics-Related Aspects of Signaling and Signal Processing for UWB Short Range Radios

A numerical model of the UWB channel created by two dipole antennas is developed to characterize the antennas and the whole channel using system level concepts such as transfer functions in the frequency domain. This model is based on rigorous numerical electromagnetic (EM) analysis, thereby enabling predictions of the channel performance under impact of different antenna geometries, their spatial arrangements, and disturbance caused by diverse factors observable in practical links. These studies of channels address to a number of important issues in electromagnetic-related aspects of UWB signaling schemas and signal processing. First, pulse shaping is developed to support signal transmission across the channel with necessary temporal and spectral features, and high efficiency of energy transmission. To this end, several realistic antennas and practical short-range radio operational scenarios are considered. Second, a system-oriented approach is presented through antenna-signal-circuitry co-design. Finally, overall system performance and hardware complexity of signaling including receiver processing are evaluated.     

Compact Ultra-Wideband Conductor-Backed Coplanar Waveguide Bandpass Filter With a Dual Band-Notched Response

This work presents a novel ultra-wideband (UWB) bandpass filter (BPF) based on a conductor-backed coplanar waveguide structure with tunable transmission zeros. The symmetrical UWB BPF, which consists of the broadside-coupled transitions and the stub resonators in double-layer configuration, achieves a UWB bandwidth with transmission zeros. For characterizing this structure, the equivalent-circuit model is established to realize a four-pole response with two transmission zeros located close to the passband edges. To eliminate the interference of the coexisting wireless local area network (WLAN) within the UWB spectrum, two slotlines are symmetrically arranged on the ground plane of UWB BPF to generate the band-notched frequencies at 5.2 and 5.8 GHz simultaneously. The proposed UWB BPFs have the advantages of compact size, low insertion loss, good selectivity, and flat group delay. All results obtained from the equivalent-circuit model and the full-wave simulation are verified by measurements.      

Study of ultrawide-band transmission in the extremely high frequency (EHF) band

The growing demand for broad-band wireless communication links and the lack of wide frequency bands within the conventional spectrum, causes us to seek bandwidth in the higher microwave and millimeter-wave spectrum at extremely high frequencies (EHF) above 30 GHz. One of the principal challenges in realizing modern wireless communication links in the EHF band are phenomena occuring during electromagnetic wave propagation through the atmosphere. A space-frequency approach for analyzing wireless communication channels operating in the EHF band is presented. Propagation of the electromagnetic radiation is studied in the frequency domain, enabling consideration of ultrawide-band modulated signals. The theory is employed for the analysis of a communication channel operating at EHF which utilizes pulse amplitude modulated signals. The atmospheric absorptive and dispersive effects on pulse propagation delay, pulse width and distortion are discussed. The theory and model are demonstrated in a study of ultrashort-pulse transmission at 60 GHz.     

Small Ultra-Wideband (UWB) Bandpass Filter With Notched Band

A compact ultra-wideband (UWB) bandpass filter (BPF) with notched band has been proposed and implemented in this letter. H-shaped slot is studied and adopted to tighten the coupling of inter-digital capacitor in order to improve the BPF's performance. Three pairs of tapered defected ground structures (DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband. Combining these two structures we obtain a small sized UWB BPF. Meander line slot is developed to reject the undesired wireless local-area network (WLAN) radio signals. An experimental UWB filter with notched band was fabricated with 35% less length as compared to an embedded open-circuited stub. The measured BPF insertion loss is less than 1.0 dB throughout the pass band of 2.8 to 10.8 GHz, the variation of group delay less than 0.20 ns in this band except for the notched band, and a wide stopband bandwidth with 20 dB attenuation up to at least 20.0 GHz.