一种新耦合结构的介质滤波器的设计与仿真

设计并研究了一种电容负载型的同轴介质滤波器,它采用新颖的耦合结构,以及高介电常数低损耗的微波陶瓷材料,大大减小了同轴介质滤波器的体积。同时用HFSS软件对其进行仿真,讨论了部分结构参数对滤波器性能的影响,最后设计出性能良好的带通滤波器,其中心频率f0=999MHz,插入损耗Li=1.489dB,3dB带宽B=17MHz,带外抑制在f0±30MHz时>20dB。     

高阻带微波带通滤波器的研制

为了提高通信设备的性能,研制了高阻带的微波滤波器。该滤波器由5个高Q值的同轴介电陶瓷谐振器构成的带通滤波器。谐振器之间通过介电基片上的电容相互耦合。在装入外壳前,调整好每个谐振器的谐振频率和耦合电容,之后就不需要再调整,外壳上也没有可调零件,从而保证滤波器结构稳定,性能可靠。用εr=74的介电陶瓷制作出滤波器的性能为f0=982 MHz,Δf=10.9 MHzI,L=3.8 dB,阻带在f0±30 MHz处大于69 dB,远阻带衰减优于70 dB。     

一种新型基片集成波导双模带通滤波器

综合基片集成波导和双模滤波器两种前沿技术,设计了一种新型微波带通滤波器结构,该滤波器结构简单,无载品质因数高达10 000。同时,通过使用凹型过渡方式,解决了基片集成波导与微带线的过渡问题,从而方便了滤波器和有源微波电路的集成。文章设计的滤波器中心频率在5.63 GHz,通过TE102和TE201两种模式耦合,产生一个传输零点,极大的改善了阻带效果。实验表明,通带内反射损耗S11优于25 dB,3 dB带宽达60 MHz。     

基于慢波特性扇形SIW的可调带通滤波器

提出了一种具有慢波特性的扇形基片集成波导谐振腔,设计了一款小型化双频带通滤波器,相较于传统SIW带通滤波器,该滤波器小型化率为64%。通过引入金属盲孔结构实现了滤波器双频带中心频率的调节,同时,采用源负载耦合结构,在带外产生了4个传输零点,实现了滤波器的高选择特性。测试结果表明,滤波器的双通带中心频率分别为4.86 GHz和6.81 GHz,3 dB带宽分别为238 MHz和212 MHz,双频带插入损耗分别优于0.9 dB和1.1 dB,与仿真结果基本一致。     

基于基片集成波导(SIW)的双模带通滤波器

首先介绍了基片集成波导(SIW)这一新技术,并用表面电流理论解释了电磁波在SIW中的传输模式。同时,通过使用凹型过渡和接地共面波导过渡两种转换方式,解决了基片集成波导与微带线的过渡问题,从而解决了滤波器和有源微波电路的集成问题。文章用这两种过渡方式,分别设计了中心频率在5.63GHz和5.45GHz的双模带通滤波器。实验表明:这两种滤波器在通带内的反射损耗S11均优于-21dB,-3dB带宽都在50MHz以上。     

2140MHz双模介质谐振滤波器的结构设计和仿

研究对于CDMA频段2 140 MHz的微波双模介质滤波器的设计原理和计算方法,同时使用高频结构仿真软件对所设计的滤波器进行了仿真分析.根据以往的双模结构,使用了利用切角进行双模耦合的新结构.所要求的滤波器的参数指标为:中心频率f0=2 140 MHz ,插入损耗IL<0.1 dB,带宽BW=10 MHz ,带内波动Ap<0.05 dB,100 MHz处带外抑制As>25 dB.仿真结果表明该结构可以更加有效地减小插入损耗,且体积比传统滤波器减小了很多,有利于器件小型化.     

结构参数对微波介质滤波器电性能的影响

利用Ansoft-HFSS仿真软件对微波介质滤波器进行建模及仿真,总结了结构参数对其电性能影响的变化规律,并提取了最优的器件结构参数.采用传统的电子陶瓷生产工艺制备样品,利用此规律指导器件的后期调试工作.结果表明,中心频率f0=2 493.0 MHz,插入损耗IL=1.539 dB,3 dB带宽BW3 dB=30.2 MHz,带内波动小于0.1 dB,在f0- 125 MHz外带外抑制Ls＞45 dB;在f0 +125 MHz外Ls＞65 dB,电压驻波比VSWR＜1.2.测试结果与仿真结果吻合,验证了该规律的可行性和正确性.     

基于新型互补开环谐振器的带通滤波器

展示了一种新型互补开环谐振器(Complementary Split Ring Resonators,CSRR).文章分析了CSRR的运行机理,研究了环缝的半径、径向间距对带通滤波器性能的影响,将该结构用于一个三阶波导带通滤波器的设计.并采用有限元法对这种结构的传输特性进行了仿真.仿真结果表明,所设计的波导带通滤波器带宽满足指标700 MHz,中心频率10 GHz,插损0.5 dB,具有体积小、性能高的特点.     

基于ADS的微波带通滤波器的研究与设计

基于ADS2009微波仿真设计系统,设计出一款适合于S波段的微波带通滤波器,本设计使用了宽带匹配技术,结合微带线和集总元件设计出宽带的匹配网络。滤波器适用频率范围:2.3 GHz~2.5 GHz,可用带宽W B=200 MHz,带内纹波小于0.5 dB,带内插损l I1 dB。实物测试结果表明,滤波器的性能参数与仿真结果高度接近,说明ADS微波仿真系统具有较高的仿真精度和较好的的实际应用价值。     

960 MHz同轴介质谐振器滤波器的研制

研制了用四个高Q值介质同轴谐振器构成的带通滤波器,谐振器之间的耦合通过陶瓷基片上的电容实现,讨论了影响谐振器插入损耗的主要因素。结果表明,该四级式低损耗介质同轴谐振器滤波器中心频率f0为960MHz,插入损耗小于3.0dB,能满足设计要求。     

一种新型基片集成波导带通滤波器的设计

基片集成波导是一种具有低差损、低辐射、高品质因数的新型平面导波结构．文中利用基片集成波导结构设计并制作了一种工作于X波段的带通滤波器,该滤波器易与其它微波平面电路集成．实测结果表明,该滤波器的中心频率是9.75 GHz,相对带宽是15.4％,通带内反射系数均小于-15 dB,插入损耗均优于1.5 dB,与仿真结果基本吻合,验证了设计方法的正确性．     

Microwave-frequency response of an optical-fibre delay-line filter

The frequency response of a single-mode fibre recirculating delay-line filter has been measured from 0 to 18 GHz using a broadband measurement system that includes an inteferometric waveguide modulator and a high-speed photodetector. An optical-fibre notch filter having a fundamental passband at 740 MHz exhibited 23 overtones that were uniform to within ±1.5 dB over the entire measurement range.     

输入输出电容对孔耦合同轴滤波器性能的影响

为了提高滤波器的电性能,研究了孔耦合两腔介质同轴滤波器的调试技术.理论上分析了耦合谐振器的频率和有载品质因数(Q)值与输入、输出电容的关系.采用介电常数εr=74的微波介质陶瓷制作了孔耦合两腔介质滤波器,通过观察反射系数(S11)波形讨论了输入、输出电容对滤波器性能的影响.结果表明,反射系数的波形和大小能直接反映出输入、输出电容的大小是否合适.最后制作出中心频率为902 MHz、通带带宽13.2 MHz、阻带衰减(f0士40 MHz)＞24.9 dB的带通滤波器.该调试技术对两腔以上介质滤波器的调试具有指导作用.     

一种新型四级叠层波导带通滤波器

提出一种新型四级叠层介质波导谐振器滤波器的结构及其设计方法。建立三维有限分析模型讨论了二级介质波导滤波器耦合特性,设计出二级片式介质波导谐振器滤波器。采用LTCC工艺叠加两块二级片式波导滤波器得到四级叠层波导滤波器,通过三维有限元分析模型绘制出四级叠层波导滤波器耦合特性曲线。最终设计出的四级叠层波导滤波器长8.8mm、宽6.2mm、厚1.6mm,中心频率5.2GHz,带宽300MHz,带内波动0.1 dB,插损0.8dB。其具有小型化、低插损以及适合表面帖装等特点,能满足下一代WLAN系统应用要求。     

四阶双模介质滤波器的设计和分析

理论分析了屏蔽腔中矩形介质的谐振频率,同时使用Ansoft HFSS对所设计的滤波器进行仿真分析。根据以往的双模结构,使用了利用切角进行双模耦合的新结构,对相邻腔体问的耦合采用耦合窗口和耦合杆相结合的方法。要求的滤波器参数指标为：中心频率f0=2140MHz,带宽BW=50MHz,插入损耗IL〈0．1dB,回波损耗RL〉22dB。仿真结果表明该结构可以更加有效地减小插入损耗,且体积比传统滤波器减小了很多,有利于器件小型化。     

A micromachining technology for integrating low-loss GHz RF passives on non-high-resistivity low-cost silicon MCM substrate

A micromachining technology for integrating high-performance radio-frequency (RF) passives on CMOS-grade low-cost silicon substrates is developed. The technology can form a thick solid-state dielectric isolation layer on silicon substrate through high-aspect-ratio trench etch and refill. On the non-high-resistivity but low-loss substrate, two metal layers with an inter-metal dielectric layer are formed for integrating embedded RF components and passive circuits. Using the technology, two types of integrated RF filters are fabricated that are band-pass filter and image-reject filter. The band-pass filter shows measured minimum insertion loss of 3.8 dB and return loss better than 15 dB, while the image-reject filter exhibits steeper band selection and achieves better than −30 dB image rejection. A 50 Ω co-planar waveguide (CPW) on the substrate is also demonstrated, showing low loss and low dispersion over the measured frequency range up to 40 GHz. The developed technology proves a viable solution to implementing silicon-based multi-chip modules (MCM) substrates for RF system-in-package (RF-SiP).     

0.22 THz Waveguide Bandpass Filter with High Stop-Band Suppression

A terahertz (THz) waveguide band-pass filter using an iris inductive window coupled structure was designed and fabricated. The filter was designed at 0.22 THz with a pass band of 20 GHz. The measured results show that the center frequency is 0.218 THz with a pass band of 0.205 THz to 0.231 THz, the minimum insertion loss is 1.26 dB at 0.224 THz, and the return loss is less than 13.1 dB. The stop-band suppression is 65.6 dB at 0.193 THz and 51.8 dB at 0.243 THz, respectively, which means a good performance of high stop-band suppression. A good agreement exists between the measured S-parameters and the simulated ones, especially in the upper band. The proposed THz waveguide filter has potential applications in THz communications.     

AN ANTI-ALIASING FILTER FOR ∑△ ADC

An anti-aliasing filter for ∑△ ADCs using a combination of active RC and analog FIR filters is presented in this letter. The first order active RC filter is set at 100kHz to minimize the die size and variations of linear phase and gain in 0-4kHz passband. The 2-tap FIR filter provides more than -53dB attenuation at 2MHz ±4kHz frequency range. The proposed filter achieved more than -76dB attenuation at sampling frequency with ±0.01° phase linearity and ±0.02dB gain variation within 0-4kHz bandwidth. The active die area of the fully differential filter is 0.17mm2 in 0.5μm CMOS technology. The experimental and simulation results have been obtained and the feasibility of the proposed method is shown.     

A nonreciprocal tunable waveguide directional filter using aturnstile open gyromagnetic resonator

The 4-port waveguide directional filter is a classic network in microwave engineering. The purpose of this paper is to describe one gyromagnetic version using an open gyromagnetic resonator in a dielectric-filled cavity. A property of the circuit is that it behaves as a 4-port circulator with one direction of circulation at one split frequency of the resonator and with the other direction for the other split frequency. An insertion loss between the coupled ports below 1.50 dB and an attenuation or isolation of typically 15 dB between the decoupled ports over most of the tuning range of the filter have been achieved. Its 3-dB bandwidth is typically 65 MHz. A typical tuning range of more than 1 GHz centered at about 10.5 GHz has been separately realized for each split branch