Microstrip Coupled-Line Lowpass Filter with Wide Stopband for RF/Wireless Systems

We present the design of a compact microstrip lowpass filter with a wide stopband which is up to ten times the cutoff frequency. The filter is based on a coupled-line configuration and shunt open stubs. The open stubs create additional transmission zeros, which are used to extend the stopband of the filter without any additional components or cascaded units. A prototype lowpass filter with a 3 dB cutoff frequency of 0.428 GHz and a 15 dB stopband extended up to 4.77 GHz is fabricated to validate the theoretical predictions.     

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.     

一种高滚降宽阻带低通微带滤波器

普通的阶梯阻抗低通滤波器滚降系数一般低于80 dB/GHz,阻带抑制小于20 dB,使其应用受到较大限制;文中首先从理论上分析并设计了具有宽阻带优势的阶梯阻抗滤波器,然后引入扇形短截线结构提高滚降系数,设计了一款通带为0~6 GHz的高滚降宽阻带的微带低通滤波器。利用ADS和HFSS分别对滤波器进行了建模、仿真和优化;最后采用RO4003板材加工并对实物进行了测试。测试结果显示,所设计的滤波器3 dB截止频率为6.02 GHz,滚降系数为123 dB/GHz,阻带6.24~20 GHz,阻带抑制大于30 dB。     

基于闭合环和短路棒的宽阻带带通滤波器

为减小微带宽阻带带通滤波器的结构尺寸,抑制滤波器的高次谐波干扰,拓宽滤波器阻带,提出一种新的基于闭合环和短路棒的紧凑型宽阻带带通滤波器.该滤波器采用闭合环和短路棒结构,将滤波器设计为改进型1/4波长谐振器结构的宽阻带带通滤波器,以达到抑制高次谐波,减小滤波器尺寸的目的.实验结果表明该方法具有良好的效果.     

2.45 GHz宽阻带高抑制腔体滤波器的研究设计

针对手持式谐波雷达发射机自身产生的谐波信号严重干扰接收到的探测目标谐波信号问题,该文设计了一种谐振器开路端加圆盘的结构,该结构能有效缩小滤波器体积和抑制高次谐振频率产生的寄生通带,并研究了圆盘半径、谐振杆长度、调谐螺钉长度和半径对腔体滤波器谐振频率的影响.结果表明,圆盘半径和调谐螺钉半径增大,则等效电容增加,谐振频率降...     

Microstrip Lowpass Filter with Very SharpTransition Band Using T‐Shaped,Patch, and Stepped Impedance Resonators

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of ?3 dB and ?20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3‐dB cut‐off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than ?20 dB is obtained while achieving a compact size with a wide stopband.     

一种窄带SIR带阻滤波器的设计

介绍了嵌入式并联λ8/4(λ8为波长)的开路支节的基本结构与特性.采用带状线,设计了一款中心频率为2.46 GHz、阻带宽度50 MHz、最大阻带衰减为60 dB的三阶嵌入式并联开路支节窄带带阻滤波器.与传统的并联开路支节带阻滤波器相比,嵌入式并联开路支节带阻滤波器的横向尺寸减小,结构紧凑.采用阶梯阻抗谐振器(SIR)结构,按相同指标设计了一款三阶嵌入式SIR窄带带阻滤波器.与嵌入式并联开路支节带阻滤波器相比,嵌入式SIR带阻滤波器结构更为紧凑,纵向尺寸缩小约17.5％,并具有更好的谐波抑制特性.     

基于折叠短截线耦合理论的新型宽带带阻滤波器设计

提出一种新型的基于折叠短截线耦合理论的宽带带阻滤波器（BSF）设计方法。根据所提出的方法,设计了一款阻带范围可控、传输零点可控、阻带抑制良好的紧凑型宽带带阻滤波器。该滤波器分为上下两部分,上部分为对称的主传输线加载折叠短截线单元,下部分是由公共短截线拓扑而成的矩形贴片。可以通过改变短截线单元的间隙耦合和矩形贴片的长度来调节阻带抑制性能和阻带范围。所提出的宽带带阻滤波器的截止频率为2.04 GHz,阻带中心频率为2.88 GHz,阻带范围为1.57~4.19 GHz,-3 dB衰减带宽达到90.9%。阻带内有三个可控的传输零点,并具有38 dB的良好抑制性能。-20 dB、-38 dB衰减带宽分别为50.3%（2.04~3.49 GHz）、36.5%（2.16~3.21 GHz）。实物测试结果与仿真基本一致。     

Compact Planar Dual‐Wideband Bandstop Filters with Cross Coupling and Open‐Ended Stepped Impedance Resonators

This letter presents the design of a compact bandstop filter (BSF) operating at two frequencies. The proposed BSF consists of open‐ended stepped impedance resonators (OSIR) and an end‐shorted parallel‐coupled microstrip line (E‐PCML). The OSIRs are used to achieve the impedance‐controlled stopband positions. The wide BSF bandwidths are achieved through enhanced coupling of the E‐PCML. Explicit design guidelines are derived using a lossless transmission line model. To validate theoretical predictions, a prototype dual‐band BSF operating at 900 MHz and 2,100 MHz with fractional bandwidths of 72% and 36% respectively, is implemented in microstrip.     

半集总元件微波低通滤波器的设计与制作

研制了一种用于混频器的微波低通滤波器。采用椭圆函数型低通原型进行设计,电感用高阻抗微带线实现,并联电容采用高Q值陶瓷微调电容器来实现。用εr=2.5的聚四氟乙烯覆铜板制作了截止频率为540MHz,级数为9的椭圆函数型低通滤波器,插损小于2dB,体积为60×40×10mm3,输入输出端为SMA或N型接头。     

双阻带特性的超宽带单极子天线设计

设计了一种具有双阻带特性的超宽带单极子天线,对嵌入开路微带谐振器和边缘相似谐振器进行了分析.利用这两种谐振器可以分别在Wimax（3.33～6 GHz ）和WLAN（ 5.15～5.85 GHz）两个频段产生阻带.通过改变天线几何尺寸,可以分别对阻带的中心频率和带宽独立控制.天线利用印刷线路板（PCB）技术加工实现,并对其阻带特性、回波损耗、辐射方向图、辐射效率和峰值增益进行了测试,测试结果和仿真结果吻合很好.     

一种新型的窄带远寄生小型化微带滤波器

设计了一种新型的窄带远寄生小型化微带滤波器,其远寄生特性通过在带通滤波器之后级联低通来实现。其中带通部分采用两阶带有调节支节的含源-负载非相邻耦合新型电路结构,文中给出其相应的拓扑与耦合系数矩阵,并分析了调节支节的作用;对于用于抑制远端寄生信号的低通滤波器,给出其集总参数原型等效电路。基于此,进行建模与仿真,设计了一款工作于S波段的微带滤波器,实测结果与仿真值、理论值有很好的吻合度,实现指标为中心频率3.93 GHz下的相对带宽8%,寄生远于12 GHz,体积27 mm×10.16 mm×7.45 mm,可以满足实际工程应用的需要。该电路结构新颖,产品尺寸小,设计方法简洁实用,适于推广应用。     

W 波段波导-微带探针过渡设计

本文采用高频仿真软件HFSS 仿真设计出了W 波段E 面探针方式的波导到微带过渡结构,并制作了实物进行了测试,实测结果表明在频率85GHz-100GHz 范围内,过渡的插入损耗小于1dB,与仿真结果基本吻合,适合工程应用。     

遗传算法应用于干涉滤光片的设计

为了设计参量更加优良的干涉滤光片,在光子晶体基础上,利用遗传算法设计了窄带滤光片、宽带阻滤光片宽带通滤光片。进行了总结并对需待完善的地方进行了说明。所设计干涉滤光片可以根据给定材料的折射率,计算出此滤光片的最优化透射率。结果表明,如果评价函数对膜系结构的微小变化敏感,用遗传算法对膜系的优化能获得好的结果和较高的效率。