复合左右手传输线的小型超宽带滤波器设计

基于复合左右手传输线的原理,设计了一款新型超宽带滤波器,结构简单且尺寸只有0.5 cm×1.5 cm,左手电容是由微带线结构耦合形成,左手电感由接地短截线形成.通过仿真结果与实物测试可知超宽带滤波器的带宽为3.3～10.2 GHz,插入损耗小于1dB,回波损耗小于-12.5 dB.该滤波器可用于超宽带无线通信系统中.     

新型CRLH传输线带通滤波器设计

设计了一种新型双负介质传输线结构,该传输线结构具有负的磁导率和负的介电常数,同传统的混合左右手(composite right/left-handed,CRLH)传输线相比,该结构以更简单的构成、更小的尺寸实现了更好的左手媒质特性。应用该结构设计制作了一个任意可调双频带谐波抑制带通滤波器,测量结果显示:该滤波器第一个通带位于2.45 GHz,具有0.5 dB的插损和56%(1 400 MHz)的3 dB带宽;第二个通带位于5.8 GHz,具有1 dB的插损和27%(1 600 MHz)的3 dB带宽。这种CRLH传输线滤波器在无线通信、导航等多频带微波系统中具有良好的应用价值。     

基于分形复合左右手传输线的小型化微带双工器设计

基于分形几何与复合左右手传输线的混合技术方法,提出了一种新型小型化微带双工器并对其进行了研究.该双工器将工作于一对不同频率的两个三端口网络进行合成,由构成其左手部分的集总元件和右手部分的Sierpinski分形微带线组成.双工器的小型化得益于Sierpinski分形曲线的空间填充特性.而双工器的双频特性是由于复合左右手...     

A microstrip folded compact wideband band-pass filter with wide upper stopband

A miniaturized wideband band-pass filter with a 3-dB fractional bandwidth of 109.3% (1.53 GHz to 5.22 GHz), high out-of-band attenuation greater than 25 dB, and wide upper stopband up to 14 GHz is proposed. The design consists of a dual-composite right/left handed resonator, embedded open-circuited stub, and a pair of quarter-wavelength short-circuited stubs. These elements are coupled in the near distance to form a miniature filter with a compact occupied area of 0.21 λ _g × 0.19 λ _g (≈ 0.013 cm²). The optimized filter has multi-transmission poles in the passband, substantially improving the return loss and insertion loss characteristics. The behavior of the passband and stopband is verified against the results of a lumped element model and matrix analysis with a full-wave moment-based analysis and actual measurements. The results of this verification and a comparison with the performance of filters in other references indicate that the proposed filter is very efficient and applicable to compact microwave systems.     

A novel compact dual-wideband BPF with multiple transmission zeros and super wide upper stopband

In this article, a novel miniaturised dual-wideband bandpass filter (DWB-BPF) based on two different resonators including a quasi-spiral loaded multiple-mode resonator (QSL-MMR) and L-shaped transmission line (LS-TL) is presented. At the first step, in order to design a single wideband BPF filter with controllable transmission zeros near the centre frequency, the open circuit impedance parameter of quasi-spiral loaded resonator Z₂₁ is determined in terms of ABCD matrix. Then an equivalent circuit model of the proposed structure is derived and the impedance characteristic and electrical length of LS-TLs to achieve a DWB-BPF with excellent selectivity are calculated through even- and odd-mode analysis. The proposed filter possesses both compact and simple structure as well as two wide passbands with fractional bandwidth (FBW) of 70% and 22.8% for its first and second passbands, respectively. The proposed technique creates two transmission zeros at the lower and upper stopbands of each passband resulting in a very sharp roll-off accompanied by a wide stopband. Notably, the circuit size is reduced and the bandwidth is enhanced in comparison with its conventional counterparts. The theoretical performance of the filter is verified by the experimental one where a good agreement is reported between them.     

基于LTC1068-200的低频带通滤波器设计

在蓄电池性能监测过程中,接收的信号都是比较微弱的低频信号,而且为了得到更多的信息,往往向蓄电池施加多个频率的激励。因此,设计带通滤波器以提高抗干扰能力,而且中心频率要可调。开关电容滤波器可实现低通、高通、带通和带阻滤波功能,而且中心频率可调节,文中采用了LTC1068-200开关电容滤波器集成模块进行电路设计,时钟频率由CD4046锁相环控制。仿真结果表明本文设计的滤波器通带宽度可以达到5 Hz,中心频率从10 Hz到1 kHz可调节,满足实际需要。     

A compact open-loop resonator filter with a wide stopband response

This paper presents a new class of microstrip slow-wave open-loop resonator filter with reduced size and improved stopband characteristics. A comprehensive treatment of both resonator ends loaded with triangular and rectangular shapes is described, leading to the invention of a microstrip slow-wave open-loop resonator. A four-resonator bandpass filter is designed at the operating frequency about 2 GHz, bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The proposed filter is not only compact size due to the slow-wave effect but also has a wider upper stopband resulting from the dispersion effect. The filter design of this type will be described in detail. The experimental results are demonstrated and discussed.     

A novel compact K band PBG microstrip structure band-pass filter

A novel K band band-pass filter based on photonic band-gap (PBG) is presented. The proposed structures exhibit low insertion loss, compact size, simple fabrication and slow-wave characteristics. Due to slow-wave characteristic, PBG structure minimizes the pass-band filter to one-tenth of conventional filters with spurious-free response and deep attenuation levels. The miniature band-pass filter was simulated, realized and measured. There is a good agreement between the experiment and simulation results had been achieved. Its center pass-band frequency of this filter is 25.2?GHz, and insertion loss is less than ?4.5?dB.     

频带展宽的复合左右手传输线偶极子天线

针对周期复合左/右手(Composite Right/Left-Handed, CRLH)传输线偶极子天线带宽窄的问题, 提出一种非周期CRLH传输线的天线模型.该模型主要由N个不同尺寸的LC梯形网络单元组成, 实现参差调谐, 改善天线的阻抗匹配, 拓展天线带宽.设计了一种四单元非周期CRLH偶极子天线, 模拟和实验测试结果表明:天线的长度为0.135λ₀时, 满足回波损耗|S₁₁|≤-10 dB的相对阻抗带宽为8.55%, 天线的匹配性能得到了改善.     

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.     

加载新型复合左右手传输线单元的宽带单极子天线设计

提出了一种新颖的一维复合左右手传输线(CRLH-TL)单元,并将其加载到传统微带馈电的单极子天线上,设计出一种宽带的变形单极子天线。该宽带天线工作在1.67~2.67GHz,相对带宽达到了46%,有效地覆盖了DCS(Digital Cellular System,1710~1880MHz)、PCS(Personal Communication Service,1850~1990MHz)、Wi-Fi(Wireless Fldelity,2400~2480MHz)等多个通信频段。首先,利用CRLH-TL的相位补偿效应,结合传统单极子天线的自身谐振,得到多个谐振工作频点;然后,通过参数优化,使得其中的两个工作频点相互靠近形成一个更宽的工作频段,并且在工作频段内获得了较好的增益和稳定的方向图。最后,对所设计的天线进行实物加工并测试,测试结果与仿真结果吻合良好。     

Tunable microstrip bandpass filter with constant fractional bandwidth based on cascade triplet topology

This paper presents an approach for designing 3-pole tunable microstrip bandpass filter with constant fractional bandwidth (CFBW). To achieve sharp roll-off responses, a cross-coupling scheme is adopted in the filter design. Cascade triplet (CT) topology and source-load coupling scheme are used to introduce three transmission zeros (TZs) in the design of 3-pole tunable filters. Thanks to tunable coupling coefficient K_c, the TZs allocated at the low-end of passbands can be tuned, which providing a reconfigurable selectivity. For the purpose of demonstration, the 3-pole tunable bandpass filters with CFBW are designed, fabricated, and measured. The proposed filter can be tuned over a wide fractional range up to 50%. The measured 3-pole filter shows a tuning range of 950–1460 MHz, with a fractional bandwidth (FBW) of 13.1% ± 2.5% and an insertion loss of 1.8–3.6 dB. Measured results of the filter present sharp roll-offs, which agree well with the simulated counterparts.     

基于微带结构的一维异向介质仿真研究

本文设计了一种基于标准微带结构的L-C传输线一维人工介质.仿真结果表明,在此种介质中传播的特定频率的电磁波表现出了明显的后向波效应,因而在此频段内可以视为具有负折射率的异向介质.     

基于半圆异向波导的新型带通滤波器

根据异向传输线原理设计了一种半圆异向波导单元,基于该单元提出了一种新型带通滤波器。利用HFSS软件对级联的四阶单元进行仿真,研究了其不同结构参数对电磁波传输的影响。用八阶单元构成中心频率为2.8 GHz的新型带通滤波器,利用HFSS软件在S波段对其进行模拟。结果为:异向通带为2.25~3.25 GHz,3 d B带宽达35.7%。利用理论分析与仿真相结合的方法,验证了该滤波器具有异向特性,与常规波导滤波器及基于微带线异向传输线实现的滤波器相比该滤波器具有小尺寸、低成本、高功率容量、低损耗、带外衰减特性好等优点。     

基于C型DGS的双通带滤波器设计

基于环形谐振器的基础结构,提出了新型C型缺陷地结构(defected ground structure,DGS)的双通带滤波器。利用C型DGS结构的高阻抗传输线特性,通过调节C型DGS结构的长度与宽度尺寸,可以实现对双频段带通滤波器的工作频段控制。最后给出了一个2.4 GHz和3.45 GHz工作频段的微带双通带滤波器设计实例,其测试结果与仿真结果吻合。     

基于金属-介质-金属结构的太赫兹超材料宽阻带滤波器

为了实现具有多频或宽频特性的太赫兹超材料滤波器,通常将相同或不同的谐振结构在同一平面内进行组合或者进行多层堆叠.通过将尺寸相同的C-型谐振单元分别置于中间介质层的两端,实现了基于金属-介质-金属结构的太赫兹超材料宽阻带滤波器,该滤波器具有较宽的阻带和较好的频率选择性.基于对该太赫兹超材料宽阻带滤波器C-型谐振结构表面的电场和电流分布的仿真分析,深入探讨了入射太赫兹波的传输机理,揭示了滤波器的滤波机制.基于对金属-介质-金属结构和金属-介质结构的超材料滤波器的滤波特性的仿真研究,揭示了宽阻带的形成机理.最后,采用PDMS薄膜制备工艺和金属磁控溅射方法对该超材料滤波器的样品进行了加工制备,并采用传输型的太赫兹时域光谱系统对其滤波特性进行了实际测试,验证了该超材料滤波器的结构设计、仿真和制备的正确性,为今后宽频带超材料滤波器的设计、制备和特性研究提供了参考.     

Compact meta-material transmission line balun based on meander lines structure and MEMS technology

This paper presents a novel compact meta-structure microstrip balun, which is characterized by left-handed properties. In the novel structure, two coupled meander lines are used to generate series capacitor and series inductor. Compared with conventional composite right/left-handed transmission-line structures, the new structure has smaller size and is easily fabricated by MEMS (Micro Electromechanical Systems) technology. Using such a meta-structure, a wide band microstrip balun is designed and fabricated. Good performance in phase error in wide pass band has been achieved.     

基于左右手传输线的贴片八木天线

运用左右手传输线的后向波理论,提出了一种新型的小型化微带贴片八木天线。该天线的有源振子部分采用左右手传输线结构;同时,为了进一步减小其物理尺寸,反射器和引向器分别采用了弯折线和微带线加载电容的结构来实现。实验结果表明,此天线的电性能优于传统八木天线,且尺寸只有传统天线的1/3。经测试,这种天线在性能上不亚于传统的八木天线。     

S波段GaAs PHEMT宽调谐比可重构滤波器芯片设计

基于单片微波集成电路技术设计了一款S波段频率可调谐滤波器芯片,该可调谐滤波器芯片采用信道化结构,通过选择不同通道实现宽调谐比。其中每个通道采用多级放大器与无源滤波网络级联的形式提高该滤波电路的选择性,通过在无源滤波网络引入变容二极管实现通道频率的连续调谐,该结构可在滤波器具备较高选择性的前提下实现宽调谐比。采用0.25 μm GaAs 赝配高电子迁移率晶体管(PHEMT)工艺设计了一款S波段双通道信道化可重构滤波器,仿真结果表明,在0~3 V控制电压范围下,该滤波器中心频率调谐范围为2.5~4 GHz,带宽变化范围为420~650 MHz,调谐比达到60%,滤波器芯片尺寸为3 mm×3.1 mm。该设计为片上可重构射频滤波实现宽频率调谐比提供了一条技术途径。     

基于波纹耦合微带线的可调谐带通滤波器

设计了一种紧凑5阶双零点可调谐带通滤波器。通过在传统梳状线滤波器中引入波纹耦合微带线结构,该滤波器可以在中心频率调谐过程中保持绝对带宽恒定,同时尺寸相较于传统方法可减小50%。谐振器中引入分布式补偿电容利于滤波器应用于高介电常数衬底的微带线结构。基于源与负载间的耦合,引入两个传输零点来提高滤波器的衰减特性。HFSS仿真结果显示,当加载的电容值为2.43 pF时,滤波器的中心频率为1.48 GHz,带宽为194 MHz,插入损耗为1.36 dB。随着加载电容值从2.15 pF增加到2.93 pF,滤波器的中心频率从1.55 GHz减小至1.37 GHz。保持绝对带宽恒定的情况下,通带内的插入损耗小于1.5 dB。