一种基于并联T型枝节的宽阻带低通滤波器

针对高低阻抗线结构的平面低通滤波器的阻带不够宽、截止频率的2倍频或3倍频处出现寄生通带、尺寸较大的问题,采用并联T型枝节代替高阻抗传输线的方法,利用T型枝节构成的带阻滤波支路,可以抑制寄生通带,增加阻带宽度,提高滤波器性能。以截止频率为4.25 GHz的七阶切比雪夫低通滤波器为例,实验结果表明,通带插损和回波损耗较小,过渡带陡峭,频率在13 GHz处的衰减低于-20 dB,阻带较宽,可以抑制3次谐波,同时滤波器的体积减小了,改善了滤波器的性能,可为低通滤波器宽阻带和小型化的设计及实现提供参考。     

微波窄带带通滤波器的设计

分析了微带线窄带滤波器设计的基本理论,借助AgilentADS仿真软件完成了中心频率位于L波段的窄带带通滤波器的设计。该滤波器选用切比雪夫的原型结构,并由耦合微带线构成,其通带为1．9GHz～2．1GHz,通带内衰减小于1．5dB,起伏小于0．5dB,在1．7GHz和2．3GHz衰减大于20dB,端口反射系数小于-15dB。版图仿真结果满足滤波器设计要求。     

零中频DVB/DAB/CMMB调谐器中可编程信道滤波器设计

介绍了应用于多模多频(DVB/DAB/CMMB)移动数字电视接收的可编程信道滤波器设计.滤波器采用0.1dB波纹的7阶切比雪夫(Chebyshev)Ⅰ型低通结构,截止频率1.8/2.5/3/3.5/4 MHz可编程,在偏离截止频率1.25/4 MHz的频点上,分别实现26/57 dB衰减.多级直流负反馈环路用于抵消因版...     

滤波器特性的非等波纹逼近方法

本文提出滤波器特性的非等波纹逼近方法。利用切比雪夫多项式构成有理函数，并与频率相关的系数组成特征函数，从而获得接近于同阶数椭圆函数滤波器的衰减特性，明显优于切比雪夫和逆切雪夫滤波器。理论明晰，过程简单，便于计算机编程。非等波纹逼近方法是最平坦逼近和等波纹逼近的一种中间形式，有其实用价值。     

具有片上数字控制频率调谐的9MHz有源RC滤波器

讨论了适用于无线局域网零中频收信机的4阶切比雪夫有源RC滤波器,为消除工艺偏差和环境变化对截止频率的影响,提出片上数字控制频率调谐电路.采用TSMC-0.25μm 1P5M CMOS工艺进行制造,测得调谐锁定时,滤波器的截止频率为9MHz,通带增益为0dB,增益波动小于1dB,带外抑制在30MHz处小于-40dB,通带内噪声小于-142dBm/Hz,当两输入信号的功率为-10dBm时,三阶交调小于-70dBm.     

具有片上数字控制频率调谐的9MHz有源RC滤波器

讨论了适用于无线局域网零中频收信机的4阶切比雪夫有源RC滤波器,为消除工艺偏差和环境变化对截止频率的影响,提出片上数字控制频率调谐电路．采用TSMC 0.25μm 1P5M CMOS工艺进行制造,测得调谐锁定时,滤波器的截止频率为9MHz,通带增益为0dB,增益波动小于1dB,带外抑制在30MHz处小于－40dB,通带内噪声小于－142dBm/Hz,当两输入信号的功率为－10dBm时,三阶交调小于－70dBm．     

基于消失模耦合的脊波导滤波器设计方法

针对传统脊波导滤波器设计中没有考虑耦合结构频率特性导致设计精度不高的问题,文中提出了一种基于消失模耦合的脊波导滤波器设计方法。该方法将工作于消失模状态下的矩形波导结构等效为频变阻抗变换器模型,通过等效电路变换将耦合结构的频变特性影响转换为对传输线谐振腔电抗斜率参数的影响,采用逐级仿真策略确定滤波器结构尺寸,避免了耗时的全波仿真优化。最后,通过一个4阶切比雪夫特性的脊波导滤波器设计实例进行验证。全波仿真结果显示了与理论设计相同的通带内等波纹特性,验证了所提方法的有效性。     

加载倒T形并联枝节的微带低通滤波器设计

针对传统的高低阻抗微带低通滤波器和开路端短截线微带低通滤波器体积较大、过渡带较缓且插入损耗较大的问题,采用高阻抗传输线单元加载并联倒T形枝节方法,构成带阻滤波支路,抑制了寄生通带,减小了滤波器面积。以7阶切比雪夫低通滤波器为例进行了设计和测试。实验结果表明,倒T形并联枝节滤波器截止频率为5.06 GHz,通带内最大插入损耗小于0.95 d B,在5.61~13.6 GHz内阻带抑制超过21 d B,而滤波器的面积比传统的开路端短截线微带低通滤波器减小20%。     

基于DGS的紧凑型低通滤波器

文中提出一种基于缺陷地结构的新型低通滤波器。其由位于微带结构顶部的加宽微带线、位于接地层中的经典哑铃型缺陷地结构（DGS）和蛇形缝隙缺陷地结构（DGS）组成,结构设计紧凑,容易调整。文中选用0.01 dB等波纹的切比雪夫型低通滤波器,分别采用哑铃型DGS、蛇形缝隙DGS替换LPF原型电路中的电感,加宽微带线替换并联电容,同时将加宽微带线产生的寄生电感考虑进去。哑铃型DGS产生的高频衰减点加宽阻带,蛇形缝隙DGS提供的低频衰减点使得通带到阻带陡峭过渡。实验结果表明,所设计的截止频率为2.54 GHz的低通滤波器具有明显的截止频率响应,通带内插损均在0.9dB以下,阻带抑制均在21dB以下。经实物加工测试验证,所设计的低通滤波器实际结果与仿真结果基本一致,具有可行性。     

一种低通带波纹的EBG带阻滤波器

分析了串联加载的电磁带隙结构(EBG)带阻滤波器的通带波纹,比较了电容、电感和并联谐振加载的影响,设计和制作了一种低通带波纹的EBG带阻滤波器。该结构共有4个周期,通过在微带线的接地面上蚀刻螺旋形结构来实现。滤波器的中心频率为2.44GHz,阻带中心衰减大于50dB,相邻通带内的波纹小于0.29dB。仿真结果与试验结果相吻合,说明了分析和设计的正确性。     

Designing IIR filters with a given 3-dB point

Often in infinite impulse response (IIR) filter design, our critical design parameter is the cutoff frequency at which the filter's power decays to half (-3 dB) the nominal passband value. This article presents techniques that aid in the design of discrete-time Chebyshev and elliptic filters given a 3-dB attenuation frequency point. These techniques place Chebyshev and elliptic filters on the same footing as Butterworth filters, which traditionally have been designed for a given 3-dB point. The result is that it is easy to replace a Butterworth design with either a Chebyshev or an elliptic filter of the same order and obtain a steeper rolloff at the expense of some ripple in the passband and/or stopband of the filter.     

基于SIW技术的毫米波滤波器研究与设计

基于基片集成波导（substrate integrated waveguide,SIW）结构设计了两款四阶的耦合带通滤波器,使用三维全波电磁场仿真软件HFSS对设计的两款滤波器进行了仿真设计和优化.由仿真结果分析得出,两款滤波器的工作频率均位于毫米波频段.第一款SIW滤波器实现了切比雪夫型响应,中心频率为20 GHz,带宽为2 GHz,通带内的插入损耗低于1.5 dB,回波损耗低于-20 dB,在阻带中对信号的衰减程度可以达到50 dB.第二款SIW滤波器实现了准椭圆函数型的响应,中心频率为29.1 GHz,带宽为300 MHz,通带内的插入损耗低于1 dB,回波损耗低于-20 dB,在通带到阻带的过渡中实现了两个陷波点.仿真结果表明,在毫米波滤波器设计中引入SIW结构,有利于优化滤波器尺寸,得到较好的滤波器性能指标,是毫米波滤波器发展的一个重要方向.     

Transmission Characteristics and a Design Method of Transmission-Line Low-Pass Filters with Multiple Pairs of Coincident Zeros and Multiple Pairs of Coincident Poles

The transmission characteristics and a design method are presented for a transmission-line Iow-pass filter with multiple pairs of coincident zeros in the finite frequency of the passband and multiple pairs of coincident poles in the finite frequency of the stopband and for a transmision-line low-pass filter with Butterworth characteristic in the passband and multiple pairs of coincident poles in the finite frequeney of the stopband. The former transmission-line low-pass filter shows an improved skirt attenuation performance and delay characteristic than a Chebyshev transmission-line low-pass filter in the same network degree. The latter type of transmission-line low-pass filter shows an improved skirt attenuation performance in comparison to a Butterworth transmission-line low-pass filter in the same network degree, it is positioned about in the middle between a Butterworth type and a Chebyshev type, the delay characteristic is improved considerably in comparison to the Chebyshev type, and the characteristic is close to that of the Butterworth type. With this design method, the connecting unit elements in addition to the stubs contribute to the attenuation response. The design example is shown on the basis of a concrete specification, and it is shown that the obtained attenuation strictly fulfills the specification.     

基于双二阶的低功耗椭圆带通滤波器设计

为解决椭圆滤波器通带纹波较大的问题,设计了一种基于双二阶的椭圆窄带带通滤波器,滤波器由3个双二阶构造的带阻滤波器级联实现,滤波器中心频率11kHz,带宽2kHz,通带纹波不超过1dB,阻带衰减不小于30dB每倍频程。滤波器功耗不超过30mW,满足水下引信接收机长时间工作的要求。     

一种宽阻带窄带腔体滤波器的设计

该文介绍了一种窄带带通腔体滤波器的原理和设计方法,通过加载电容原理,使滤波器的寄生通带远离通频带,并设计了带哑铃型横杆的谐振器结构,在谐振器连接点形成电压驻波零点,从而进一步抑制滤波器的寄生通带,实现了具有宽阻带的带通腔体滤波器。最后,利用微波仿真软件CST设计了一款中心频率为2.45 GHz,相对带宽为4.08%的窄带带通腔体滤波器。仿真结果表明,滤波器带外抑制高,阻带范围宽,通带内驻波良好,满足设计指标要求。     

A low power high linearity baseband for a direct conversation CMMB tuner

An analog baseband circuit made in a 0.35-μm SiGe BiCMOS process is presented for China Multimedia Mobile Broadcasting (CMMB) direct conversion receivers. A high linearity 8th-order Chebyshev low pass filter (LPF) with accurate calibration system is used. Measurement results show that the filter provides 0.5-dB passband ripple, 4% bandwidth accuracy, and -35-dB attenuation at 6 MHz with a cutoff frequency of 4 MHz. The current steering type variable gain amplifier (VGA) achieves more than 40-dB gain range with excellent temperature compensation. This tuner baseband achieves an OIP3 of 25.5 dBm, dissipates 16.4 mA under a 2.8-V supply and occupies 1.1 mm2 of die size.     

A 1-V +31 dBm IIP3, Reconfigurable, Continuously Tunable, Power-Adjustable Active-RC LPF

This paper proposes a biquad design methodology and presents a baseband low-pass filter for wireless and wireline applications with reconfigurable frequency response (Chebyshev/Inverse Chebyshev), selectable order (1st/3rd/5th), continuously tunable cutoff frequency (1-20 MHz), and adjustable power consumption (3-7.5 mW). A discrete capacitor array coarsely tunes the low-pass filter, and a novel continuous impedance multiplier (CIM) then finely tunes the filter. Resistive/capacitive networks select between the Chebyshev and inverse Chebyshev approximation types. Also, a new stability metric for biquads, minimum acceptable phase margin (MAPM), is presented and discussed in the context of filter compensation and passband ripple considerations. Experimental results yield an IIP3 of 31.3 dBm, a THD of -40 dB at 447 mV_{pk, diff} input signal amplitude, and a DR of 71.4 dB. The filter's tunable range covers frequencies from 1 MHz to 20 MHz. In Inverse Chebyshev mode, the filter achieves a passband group delay variation less than plusmn2.5%. The design is fabricated in 0.13 mum CMOS, occupies 1.53 mm² , and operates from a 1-V supply.     

A new 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications

This paper proposes a new current-mode 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications. The design is based on the state-space synthesis method. The proposed filter has 5.75 MHz cut-off frequency with maximum 0.177 dB passband ripple and attenuation greater than 40 dB at 7.88 MHz. Only BJTs and grounded capacitors were used, and operated with single power supply of 2.5 V. Since the parameters of proposed filter are tunable, it is easy to control of cut-off frequency. This adjustment is accomplished by changing external currents. SPICE simulations are given to confirm the theoretical analysis. For this purpose, the filter is simulated by using both idealized BJT models and AT&T CBIC-U2 type transistors.     

三阶级联复数有源RC带通滤波器

采用0.18μmCMOS工艺设计了一款应用在无线传网中的三阶级联有源RC复数带通滤波器,同时设计了自动频率调谐电路(AFT)。该滤波器采用的是切比雪夫逼近函数予以实现。在5比特数字控制码开关电容阵列的控制下,AFT电路即可完成对主体滤波器电路频率变化的校正。仿真结果显示,滤波器的中心频率稳定在2MHz,通带带宽为2MHz,镜像抑制比大于34dB,相邻信道阻带衰减大于34dB,通带纹波小于1dB,消耗电流为2.3mA,工作电源电压为1.8V。     

IIR数字滤波器的Matlab和FPGA实现

提出一种通过两个二阶节级联构成四阶IIR数字椭圆滤波器的设计方法,并利用Matlab仿真软件设计了通带内波纹不大于0.1 dB,阻带衰减不小于42 dB的IIR数字滤波器。论述了一种采用可编程逻辑器件,通过VHDL硬件描述语言实现该滤波器的方法。给出了在QuartusⅡ软件下的仿真结果,并在FPGA器件上验证实现。实验证明,这种方法是切实可行的。