可调谐光纤F-P线性滤波器的设计与分析

光纤滤波器在光纤通信和光纤传感领域发挥着重要的作用。本文基于光学薄膜干涉理论设计了一种用于光纤传感的可调谐F-P线性滤波器,该滤波器由两端面相对的入射光纤与出射光纤构成,两光纤端端面分别镀有反射光纤薄膜。该F-P干涉腔改善了传统F-P腔的透射率响应特性,有助于提高滤波器的线性度和线性范围。本文采用光学薄膜干涉矩阵分析法对该滤波器的透射率响应关系进行了计算与分析,并得出该FP滤波器的结构参数。设计结果表明,这种新型线性滤波器具有线性度好、线性范围宽和线性区间可调的优点。     

可调频率跨导电容Chebyshev滤波器的设计及仿真

首先提出了一种新的跨导运放,其输入级采用了工作在线性区的MOS管作源极负反馈有源电阻实现其良好的线性度,输出级采用折叠式结构,并在电路中引入电压共模负反馈(CMFB)稳定其静态工作点。接着提出了一种新的利用开关电容技术调节跨导运放偏置电流值大小的电路,应用该电路可以精确调节跨导运放Gm值的大小,应用这些电路设计得到了四阶Chebyshev低通滤波器,并实现其频率的精确可调,0.35μm2层多晶硅,4层金属CMOS工艺Spicemodel仿真结果表明设计正确、有效。     

Design of a compact microstrip tunable dual-band bandpass filter

A novel microstrip tunable dual-band bandpass filter with high attenuation level in the upper stopband region is presented. The proposed structure comprises of T-shaped resonators and the coupled microstrip feeding lines. To reach a compact size, the feeding lines are bended. By altering the physical lengths, the characteristics of BPF can easily tune. So, the operational frequencies of the filter can be adjusted and has been fixed to 2.1 GHz and 2.63 GHz, which are applicative for 3G and 4G systems. The insertion-losses of the first and second pass-bands are only 0.68 dB and 1.08 dB, respectively. The undesired harmonics in the upper stopband, with an excellent attenuation level of −38 dB, are rejected up to 6.65 GHz. The results exhibit high return loss of 19.3 dB and 30.7 dB in the first and second pass-bands. The proposed circuit has been fabricated and tested that the obtained results are well close to the simulations results. The total size of the designed circuit is only 16.4 × 13.4 mm².     

一种基于TFF的50GHz平顶型可调谐光滤波器

文章介绍了一种基于薄膜滤光片(TFF)技术的50 GHz通道间隔、平顶型可调谐光滤波器(TOF)的研制.对角度调谐干涉滤光片的原理进行了讨论,同时对超窄带膜系设计进行了优化.研制出的器件样品经过全面测试,实现了40 nm波长范围内96个ITU-T通道的可选择下路,为智能化的光网络提供了一种低成本、高性能的动态波长选择方案.     

新型三角贴片加槽双模滤波器的设计

为了实现微波滤波器的小型化,文中设计了一个新型的三角贴片加槽双模滤波器。通过加槽的设计,使谐振器的工作频率进一步降低,从而实现了滤波器的小型化及低损耗;同时研究了该结构尺寸参数的变化对通带中心频率的影响。最后利用HFSS对滤波器进行了仿真,得到工作频率为2.352～45 GHz以及5.64～5.65 GHz的双通带带通滤波器。整个滤波器采用微带结构,经过仿真优化,得到的滤波器的滤波特性符合预期的要求。     

液晶损耗对可调谐液晶光学滤波器性能的影响

F- P型可调谐液晶光学滤波器是一种小体积窄带宽低压调谐滤波器。液晶作为腔内工作物质,其损耗对器件的性能有重要的影响。文章以F- P干涉仪为基础,分析了液晶损耗对这类滤波器的半强度带宽(FWHM) 和峰值透过率的影响,以利于不同要求的滤波器的设计制作。     

Design of a tunable frequency CMOS fully differential fourth-order Chebyshev filter

A new fully differential amplifier and a fully differential R-MOSFET-C fourth-order Chebyshev active lowpass filter employing passive resistors and current-steering MOS transistors as variable resistors are proposed. The implementation relies on the tunability of current-steering MOS transistors operating in the triode region which counteract the deviation of resistors in integrated circuit manufacturing technology in order that the cutoff frequency of Chebyshev active filter can be realized accurately tunable. The amplifier is not only with voltage common-mode negative feedback (VCMFB), but also with current common-mode negative feedback (CCMFB), which will benefit for the stability of its DC operating point. A cutoff frequency of 138 kHz fourth-order Chebyshev lowpass filter was designed and fabricated using 3.3 V power supply and 0.35 μm CMOS technology. Chip test results demonstrate better than −68 dB THD with 70 kHz, 2.0V_pp signal, frequency turning range of more than 14,000 from 3 Hz to 420 kHz, chip area of 0.36 mm² and power consumption of 16 mW.     

Design and analysis of a dynamic code division multiple access communication system based on tunable optical filter

A dynamic optical code division multiple access (DOCDMA) communication system is proposed for high-bandwidth communication systems. An implementation of the system is proposed based on a fast tunable optical filter (TOF) in each encoder and decoder. This technique actively modulates the central wavelength of a TOF according to a functional code at the transmitter during the bit period before the transmission of the data. The system is modeled and analyzed taking into account multiple access interference (MAI), thermal noise, and phase-induced intensity noise (PIIN). The performance of this system is compared to that of a spectral amplitude coding system that uses either a Hadamard code or a modified quadratic congruence (MQC) code. The results show that the proposed DOCDMA system reduces the PIIN effect on the performance of the system and improves the bit error rate (BER) performance at a large number of users. Furthermore, it is found that when the effective power is large enough, the MAI becomes the main factor that limits system performance, whereas when the effective power is relatively low, both thermal noise and PIIN become the main limiting factors with thermal noise having the main influence.     

一种大功率窄带电调滤波器设计

针对电调滤波器失谐和控制精度问题,提出采用参数扫描优化法设计腔间耦合孔、改变输入输出耦合环形状的补偿结构设计方法,采用运动机构和软件相结合的闭环控制系统,设计了调谐精度高(25 kHz)、窄带(f0×0.25%MHz,f0为中心频率)、大功率(100W)的电调滤波器,已应用于工程实际,具有较好的应用前景。     

基于可调谐FP滤波器的光纤光栅解调系统

为了进一步提高光纤光栅解调系统的性能,提出和研究了一种新颖的基于可调谐F-P(Fabry-Perot)滤波器的光纤光栅解调技术,并以此为基础构建了探测系统。系统使用一个固定波长的参考光纤光栅作为波长参考元件,通过对传感光纤光栅与参考光纤光栅的波长测量与差值运算,消除了可调谐FP滤波器腔长漂移对测量精度的影响。给出压电陶瓷电压对应的伸长量,有效地减小了压电陶瓷非线性对测量的影响,提高了光纤光栅波长的测量精度。在测量范围内,最大非线性偏差为0.5%。     

新型光纤声光可调滤波器的宽带信号放大器设计

为了改进现有宽带信号放大器的设计并优化器件的性能,采用了基于新型声致光纤光栅光路的设计方法,通过对放大器的理论的计算和调试,针对产生声致长周期光纤光栅所需的MHz量级声波信号需要,设计了一个新型射频放大电路.进行了理论分析和实验验证,取得了声致光纤光栅透射光谱中谐振峰的透射深度检验放大电路的性能数据,结果表示:该放大器能够满足产生声致长周期光纤光栅的器件要求,这一结果对大幅改善和优化宽带信号放大器的性能是有帮助的.     

一种新型SIR结构LTCC带通滤波器设计与制作

采用低温共烧陶瓷(LTCC)技术及SIR结构,设计制作了一种新型LTCC带通滤波器,采用ADS和HFSS软件进行三维建模和电磁场优化仿真及测试。结果表明:该滤波器中心频率为2.46 GHz左右,3 dB带宽为2.28~2.71 GHz,带外抑制≥25 dB(偏离中心频率±500 MHz),外形尺寸为3.20 mm×1.61 mm×1.03 mm。     

一种基于可调谐F-P腔滤波器的光分插复用器

文章提出了一种基于可调谐F-P腔滤波器的光分插复用器(0ADM),对它的串扰特性进行了详细的分析与计算,提出了减小串扰的改进措施;实验中,下载波长谱线宽度仅为0.18 nm,插损为4.2 dB,信道隔离度大于26.5 dB,自由光谱范围(FSR)大于33nm.该OADM具有结构简单、隔离度高、可精密调谐、插损小、成本低和功耗低等特点,可广泛应用于现有的密集波分复用(DWDM)系统.     

基于FBG传感系统的可调光滤波器非线性研究

采用光纤布拉格光栅(FBG)传感系统研究压电陶瓷(PZT)驱动法布里-珀罗(F-P)型可调谐光滤波器(TOF)的非线性特性。基于多光束干涉理论建立了TOF的非线性模型,推导了透射带波长和自由光谱范围(FSR)对驱动电压的非线性响应;基于FBG传感系统测试了F-P型TOF的波长非线性,并采用多项式拟合对其进行描述,实测F-P型TOF波长的非线性误差最大为1.006 nm;基于F-P型TOF的非线性模型,研究了其波长定位误差,并提出采用参考光栅的方法降低波长定位误差。实验表明,F-P型TOF的波长随机误差可由73～81 pm降至12 pm以下。     

低电压驱动的MEMS F-P可调光学滤波器研究

基于微机电系统（MEMS）技术,研制了一种新颖的光学腔与静电驱动器分离的Fabry-Pérot（F-P）可调谐滤波器。从光学设计、MEMS结构设计、制造工艺与器件测试等开展了F-P可调谐滤波器的研究,成功制备了工作在以1550 nm波长为中心、调谐范围为40 nm和驱动电压低于30 V的MEMS F-P可调滤波器。测试...     

基于单片机的UHF电调滤波器的实时调谐设计

为实现多部通信机在近距离内以邻近的频率互不干扰的正常工作,有效方法就是在接收机的输入端和输出端接入具有实时调谐功能的窄带高Q滤波器.提出了基于单片机的UHF电调滤波器的实时调谐设计,给出硬件结构图以及驱动和检测单元电路,并给出设计流程.     

基于液晶的可调谐太赫兹双折射滤波器的设计

液晶双折射滤波器具有室温下工作,调谐简单方便,带宽窄等优点。为了达到设计不同调谐范围和带宽的这种滤波器的目的,以满足实际应用的需要,扩大其应用范围,采用数值模拟的方法,进行参数计算和设计思路的总结,并设计了一套窄带输出的滤波器实例。结果表明,通过对影响滤波器调谐范围和输出带宽的关键参数的数值模拟和分析,为设计不同调谐范围的液晶双折射滤波器提供了依据;设计实例基本上满足预期的设计要求,调谐范围0.691~0.866 THz。     

Design and analysis of a structure-based microstrip bandpass filter

A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure （DGS） technology. A double-mode coupling resonator combined with DGS structure was used to achieve the resonance frequency and the filter size. CST microwave studio was used to optimize the attenuation performance to get the filter parameters. A structure-based passband filter was fabricated. Simulation is consistent with the measurement. Performance shows that the proposed filter could be suitable for the time division-long term devolution （TD-LTE） microwave systems at 2.6 GHz.     

新型高抑制波导滤波器设计

提出了一种新颖的波导带通滤波器设计。该滤波器是一个四阶广义切比雪夫滤波器,中心频率为9.93GHz,带宽为200 MHz,插损小于0.5 dB,带内回波损耗大于20 dB。谐振器为CQ结构,通过一个矩形波导膜片(一个不完全高度的导电杆),实现了交叉耦合,相比传统方法,产生一个额外的传输零点。由于在高端产生了两个零点,使得滤波器在阻带高端10.1 GHz处的带外抑制达到了35 dB以上。仿真实验证明了该设计方法能显著提高滤波器的带外抑制,对滤波器的小型化、高性能化有一定的意义。