小型化多层双模基片集成波导平衡带通滤波器

针对平衡滤波器小型化和高选择的应用需求,提出两种新型的多层双模基片集成波导平衡带通滤波器。首先详细分析了基于平衡端口馈电的双模基片集成波导谐振器的特性;然后根据谐振模式分布特性,设计了一种输入输出馈线同时在上层双模谐振器上的四阶平衡带通滤波器,下层双模谐振器通过十字交叉槽线结构与上层谐振器耦合,可以实现三个传输零点;又提出一种输入和输出馈线分别在上层和下层双模谐振器上的四阶平衡带通滤波器,上层和下层谐振器通过一个槽线进行耦合,可以实现两个对称的传输零点。基于提出的两种平衡滤波器结构,分别设计了一个中心频率为10 GHz的平衡带通滤波器,并进行加工和测试。测试和仿真结果一致性较好,表明了该结构可以实现小型化和高选择,并且具有很好的共模抑制特性。     

基于新型四模谐振器的双通带带通滤波器设计

提出了一种新型的基于双枝节加载的T型四模谐振器,并且利用该谐振器设计了一款双模双通带带通滤波器。首先利用奇偶模分析法以及场分布分析法对四模谐振器的频率特性进行分析,谐振器的每一个谐振模式均可以被独立调节。然后对馈线枝节的参数进行了详细的分析,得到馈线对滤波器外部耦合系数的影响,以调整滤波器通带的带通宽度。接着分析滤波器传输零点产生的原因,得到零点变化的规律,从而调整零点位置,提高滤波器的选择性。缺陷地结构(DGS)被蚀刻在滤波器的金属层底面,以引入非谐振节点,提供源与负载的耦合,可以产生额外的传输零点,进一步提高滤波器的选择性,而且不会增大滤波器的体积。对该滤波器进行加工和测试,仿真结果与测试结果基本吻合。     

基于双SSLR的小型化双通带带通滤波器设计

设计了一种新的具有良好选择性的小型化的双模双通带带通滤波器。该滤波器的谐振结构由两个短路枝节加载谐振器(SSLR)连接到同一个接地金属柱构成。首先通过奇偶模分析方法分析单个SSLR的谐振频率,得到谐振频率的变化规律;然后为了实现滤波器的小型化,将两个SSLR连接到同一个金属柱上并且折叠微带线,通过调节枝节长度分析滤波器通带的变化;设计中使用双枝节分别对谐振器馈电的结构,并且引入了源与负载耦合,可以在上阻带多提供一个传输零点,以提高阻带抑制;最后对滤波器的传输零点进行分析,提高滤波器的选择性。通过上述的分析,对该滤波器进行仿真、加工以及测试,得到最后实物的测试结果与软件的仿真结果较为一致。     

CDMA移动通信用高温超导滤波器的研制

本文提出了一种新型H型环带谐振器,具有结构紧凑,尺寸小,Q值高,非相邻耦合弱等优点.该谐振器在一侧设置了一个开口,改变开口位置,可以在较大范围内改变谐振器谐振频率,并且能够改变基频和二倍谐频之间的频率间隔.对于直连型馈线引入方式,H型环带谐振器容易实现外部Q值的匹配,同时对输入/输出端谐振器的谐振频率影响很小.本文还基于H型环带谐振器,采用2英寸双面YBCO高温超导薄膜设计并制作了用于CDMA移动通信系统的12节高温超导滤波器.该滤波器的中心频率为832MHz,相对带宽为1.6%.在70K温度下的测试结果显示滤波器的带内插入损耗低于0.28dB,反射损耗优于-15.5dB,带外抑制约为75dB,通带低频端带边陡峭度超过30dB/MHz,高频端带边陡峭度超过20dB/MHz.     

一种高选择性可调带通与带阻可切换滤波器

设计了一种高选择性可调带通与带阻可切换微带滤波器。在微带谐振器及枝节末端加载变容二极管实现中心频率的可调;在输入与输出端口馈线之间,利用PIN二极管实现滤波器阻带和通带特性的切换。采用奇偶模的方法对滤波器结构进行分析,通过对奇偶模频率的调节实现了频率调节过程中的恒定绝对带宽。同时,在输入与输出馈线间引入源与负载耦合,使得频带两侧各有一个传输零点,且传输零点在整个频率调谐范围内相对位置几乎不变。因此,在整个频率调节范围内,滤波器实现了高选择性及良好的带外抑制能力。最终设计出的可调带阻滤波器的频率调谐范围为5.58～5.89 GHz,绝对带宽80 MHz±5 MHz,阻带衰减优于14 dB;可调带通滤波器的频率调谐范围为5.42～5.79 GHz,绝对带宽120 MHz±5 MHz,插入损耗1.69～2.25 dB,回波损耗优于13 dB。同时,该滤波器具有0.28λ_g×0.62λ_g（λ_g是可调频率范围中心频率的波长）的紧凑结构尺寸。实验和仿真结果一致性较好。     

具有宽阻带特性的6阶自均衡高温超导滤波器

本文提出了一种新颖的L型阶跃阻抗谐振器,该谐振器具有结构紧凑、抑制二次谐波能力强及易于实现电耦合及磁耦合等特点。使用该谐振器设计并制作了一款具有小型化、高选择性及宽阻带特性的6阶自均衡高温超导滤波器。测试结果表明,在70 K温度下滤波器的中心频率为1 601 MHz,3 dB带宽为24 MHz,带内回波损耗<14.87 dB,带内最大插入损耗约为0.22 dB,60%带宽范围内群时延起伏<3.13 ns,通带两侧具有一对深度的传输零点,实现了1 632~5 511 MHz范围内衰减>60 dB的宽平坦阻带。     

自均衡相位特性的超导滤波器小型化设计

提出了一种具有多个传输零点的高温超导滤波器小型化设计方法。该滤波器由十个慢波交叉指结构谐振器和三个自均衡CQ跨线结构组成,其中一个CQ结构通过产生一对实轴上的传输零点实现相位均衡,另外两个CQ结构通过产生两对虚轴上的传输零点实现滤波器的高频率选择性。滤波器中心频率为1,720MHz,带宽为10MHz,通带外陡峭度为40d B/MHz,通带内回波损耗为23d B,且在60%的通带内具有平坦的群时延响应。在Mg O衬底上采用DBCO高温超导薄膜制作十阶超导滤波器,并在77K温度下进行测试,最终得到了良好的带外抑制性能和平坦的群时延特性。测试结果与仿真结果基本一致,说明所提出的设计方法是有效的。     

基于一维金属开口谐振环的可调带通滤波器

利用等效LC谐振电路,分析了开口环的谐振频率与等效电路电参数之间的关系.区别于传统微带传输线及附属开口环结构,本文设计了两种以开口环作为传输媒介的结构.对两种结构仿真和实验测试,实现了带宽分别为300MHz和200MHz的带通滤波器的设计,并在开口谐振环外环一侧加载变容二极管及偏置电路实现通带频率的连续可调.从表面电流密度分别分析了两种结构的传输特性,在通带内,方环的传输系数比圆环高3dB,其中结构之间的等效间距是影响传输效率的一个重要因素.     

UHF波段宽阻带高温超导滤波器设计

在分析电容加载的微带线谐振器模型的基础上,提出一种基于叉指电容、块状电容和弓形折线电感的新颖谐振器,其第一谐频位于5.6f_0外。利用该谐振器,在28mm×12mm×0.5mm的YBCO/MgO高温超导基片上设计制作了4节超导滤波器,中心频率为500MHz,相对带宽为1%。测试结果表明该滤波器具有优异性能,带内插损小于0.3d B,反射损耗优于15d B,通带与5.6f_0处寄生通带之间的抑制度大于75d B,实现了宽阻带和高抑制度的带外抑制特性。     

Wi-Fi频段体声波滤波器的设计

为了保证移动设备在Wi-Fi频段正常工作且不受相邻频段的干扰,设计了一种用于Wi-Fi IEEE802.11b频段(2402~2482 MHz)的BAW滤波器。设计基于薄膜体声波谐振器(FBAR)的一维Mason等效电路模型构成初始结构的梯形滤波器。然后,将串联FBAR的谐振区面积值以及串、并联FBAR的谐振区面积的比值设置为优化参数,以所需的滤波器的带内插损和带外抑制为优化目标,使用ADS软件基于遗传和梯度的优化算法对滤波器进行优化。在滤波器的设计过程中,为了使仿真结果更加精确,采用声电磁协同仿真方法对滤波器进行仿真,并与Mason 等效电路模型仿真结果对比,结果表明,滤波器性能有所下降,带内插损增大1.6 dB,带内纹波增大1.1 dB,带外抑制基本一致。所设计的Wi-Fi频段的BAW滤波器具有低插入损耗(小于3 dB)、高带外抑制(大于40 dB)性能。     

Selective mode suppression in microstrip differential lines by means of electric-LC (ELC) and magnetic-LC (MLC) resonators

In this paper, it is demonstrated that the so-called electric-LC (ELC) resonators, and their dual counterparts, the magnetic-LC (MLC) resonators, are useful for the selective suppression of either the differential or the common mode in microstrip differential lines. The key point to mode suppression is the alignment of the resonator with the electric (differential mode) or magnetic (common mode) wall of the line. It is shown that by simply rotating the resonators 90^° we can selectively choose the suppressed mode in the vicinity of the resonator’s fundamental resonance frequency. The theory is validated through full-wave electromagnetic simulation, the lumped element equivalent circuit models of the proposed structures and experimental data.     

Design of a broadband μ-negative planar material with low frequency dispersion

Compared with the traditional split-ring resonator reported by Pendry et al. (IEEE Trans. Microw. Theory Tech. 47:2075, 1999), the co-directional split-ring resonator, which has inherent low mutual coupling between its outer and inner rings, can provide distinct dual-band magnetic resonances. In this paper, we analyzed and compared different types of split-ring resonator, but selected the co-directional split-ring resonator for the tri-band magnetic resonator design because of its attractive dual-band magnetic resonance characteristics. We then accommodated the rings’ resonant strengths in the co-directional split-ring resonator to be nearly equal, and added an arm-loaded ring to design a new tri-band magnetic resonator. Finally, we designed and experimentally demonstrated a broadband μ-negative planar material with low frequency dispersion, which consisted of three pairs of tri-band magnetic resonators with slightly different dimensions.     

A three-mode microstrip resonator and a miniature ultra-wideband filter based on it

An original microstrip resonator design with a strip conductor split by a slot at one of its ends is investigated. It is demonstrated that at the optimal slot sizes, when the eigenfrequency of the second oscillation mode hits the center between the first and third oscillation modes, the resonator can work as a thirdorder bandpass filter. The structure formed from only two such resonators electromagnetically coupled by split conductor sections is a miniature six-order wideband filter with high selectivity. The test prototype of the filter with a central passband frequency of ~1.2 GHz and a passband width of ~0.75 GHz fabricated on a substrate ~(45 × 11 × 1) mm³ in size with a permittivity of 80 is characterized by minimum loss in a passband of 0.5 dB. The parametric synthesis of the filter structure was performed using electrodynamic analysis of the 3D model. The measured characteristics of the test prototype agree well with the calculated data.     

Self-coupled dual-mode ring resonator with turning transmission zeros in microwave bandpass filter for planar metamaterial: analysis and design

An H-shape dual-mode closed resonator with self-coupled segments is reported. The self-coupling between ring segments renders an equivalent mode perturbation effect as the normal ways of adding stub, cutting notch, or varying line impedance to the ring resonator. The mode perturbation and transmission-zero generation from the self-coupling effect and step-impedance were analyzed using the even–odd mode theory. By regulating the impedance ratio and coupling coefficients of self-coupled sections, the self-coupled ring resonator can produce either the capacitive or inductive perturbation. The input and output positions affect the number and locations of transmission zero. The positions of input and output ports are properly selected. In the capacitive perturbation case, when the two transmission zeros are located on both sides of the passband, and bring about a pseudo-elliptic bandpass response. The analysis of finding optimized taping positions of input and output ports is proposed. Comparing to the regular uniform ring resonator, the H-shaped self-coupled ring resonator has shorter ring length, is easily to be folded and does not destroy the dual-mode characteristics. The feature of compact size is favorable in the design of a bandpass filter. A 2.45-GHz bandpass filter based on the H-shaped self-coupled ring resonator was performed to verify the proposed theory. A schematic bandpass filter was implemented with a compact size which is only 20% of the conventional dual-mode bandpass filter.     

Ka波段波导滤波器的设计

采用高精度三维电磁场分析软件对电感膜片建模,并与等效电路相结合设计波导带通滤波器。实验结果表明,样品测试结果与仿真结果基本吻合,该方法不仅适合波导滤波器设计,也适合其它谐振器耦合结构滤波器的设计。     

用于集成光学陀螺的波导谐振腔设计

给出了一种集成光学陀螺谐振腔的优化设计方案,在保证集成光学陀螺精度的同时更利于微型化。选用传输损耗为0.01dB/cm的硅基二氧化硅材料作基底,谐振腔内损耗仅为0.5dB,保证了谐振腔的高清晰度;采用准单模矩形波导结构,利用弯曲波导对一阶模的有效限制实现了光的基模传输,利于谐振腔的小型化;分析了波导的传输损耗、波导耦合器分光比对谐振腔性能及陀螺极限灵敏度的影响,得出波导耦合器分光比的优化参数,并仿真得到谐振腔的谐振清晰度达到70以上。在激光器线宽为30kHz,探测器响应度0.95A/W,积分时间为10s的条件下,系统的极限灵敏度为1.6°/h。     

Prediction and suppression of strong dispersive coupling in microracetrack channel drop filters

For a four-port microracetrack channel drop filter, unexpected transmission characteristics due to strong dispersive coupling are demonstrated by the light tunneling between the input-output waveguides and the resonator, where a large dropping transmission at off-resonance wavelengths is observed by finite-difference time-domain simulation. It causes a severe decline of the extinction ratio and finesse. An appropriate decrease of the coupling strength is found to suppress the dispersive coupling and greately increase the extinction ratio and finesse, a decreased coupling strength can be realized by the application of an asymmetrical coupling waveguide structure. In addition, the profile of the coupling dispersion in the transmission spectra can be predicted based on a coupled mode theory analysis of an equivalent system consisting of two coupling straight waveguides. The effects of structure parameters on the transmission spectra obtained by this method agree well with the numerical results. It is useful to avoid the strong dispersive coupling region in the filter design.     

基于CSMRC结构和容性肖特基二极管的220GHz三倍频器

设计了基于容性肖特基二极管的220 GHz非平衡三倍频器。首先对容性肖特基二极管进行测试和关键参数提取,建立了肖特基二极管的等效电路模型,以此为基础进行三倍频电路设计;在倍频电路设计中通过引入紧凑悬置微带谐振单元(CSMRC)滤波结构来减小信号传输损耗;由于三倍频电路设计中难以实现全波阻抗匹配,因此采用了整体电路结构谐波平衡调匹配方法设计倍频电路,最后对制备出的倍频器进行测试和分析;实验测试结果表明:倍频器在213.1~221.6 GHz范围内输出功率大于10 mW,倍频效率大于5%,最高输出功率为18.7 mW@218.6 GHz,最高倍频效率为8.24%@217.9 GHz。