幅度校准功能的低附加相移数控衰减器

提出了一种可用于Ka波段相控阵系统的高精度低附加相移五位数控衰减器（Digital Controlled Attenuator,DCA）。该DCA采用了嵌入式开关的T型、简化T型和Π型三种衰减结构设计基本衰减单元，实现了15.5 dB的衰减动态范围和0.5 dB的最小衰减步进。幅度校准技术被用于信号通路中，可有效降低由工艺波动引起的衰减幅度误差增大问题，增强了电路设计的鲁棒性。同时，在T型和Π型衰减结构中采用电容补偿技术提高其高频衰减性能，实现低附加相移。基于65 nm CMOS工艺，对所提出的DCA进行了优化仿真、流片与测试验证。芯片核心尺寸为500μm×150μm。测试结果表明：在25～35GHz频带范围内，参考态插入损耗为6.54～8.6dB,32衰减态对应的输入/输出回波损耗优于-15 dB，幅度误差RMS和相位误差RMS分别为0.12～0.26 dB和1.02°～2.07°。     

GaAs基双相压控衰减器MMIC设计

基于0.25μm砷化镓赝配高电子迁移率晶体管工艺,设计一款工作在13～16 GHz的双相压控衰减器。电路采用平衡式结构,以获得小的输入、输出回波损耗;衰减器部分采用T型衰减结构和π型衰减结构级联的方式;并联支路采用多栅开关管串联的形式,减小寄生,提高线性度。仿真结果表明,所设计的压控衰减器在工作频带(13～16 GHz)内,输入、输出回波损耗小于-14 dB,插入损耗为-12. 5 dB,衰减范围达到20 dB以上,输入1 dB压缩点大于30 dBm,芯片尺寸为1. 8 mm×1. 2 mm。     

S波段数控衰减器芯片设计与实现

采用0.5μm Ga As PHEMT工艺设计了一款工作于2.7GHz~3.5GHz的3bit数控衰减器芯片,经过测试通态插入损耗0.7d B,最大衰减量5.6d B,衰减步进0.8d B,衰减平坦度≤0.1d B,衰减精度±0.2d B,全态输入/输出电压驻波比系数1.25,全态衰减附加相移在-3°~2°之间,芯片面积1.04mm×1.2mm。     

一种低成本光通信用MEMS可变光衰减器

介绍了一种采用新型体硅微机械加工工艺研制的低成本光通信用微机械可变光衰减器.根据光通信系统对可变光衰减器的插入损耗低、动态衰减范围大、响应时间短等技术要求,对器件的机械模型结构和光耦合模型结构进行了分析.测试表明器件的动态衰减范围≥50dB,插入损耗≤0.8dB,回波损耗≤-45dB,波长相关损耗≤0.2dB,偏振相关损耗≤0.25dB,响应时间＜1 ms.     

一种微波附件组合的设计与实现

在综合测试与诊断领域,随着被测系统复杂性的提高,对测试系统准确度要求进一步提高。文中设计实现了一种微波附件组合,主要由微波开关、衰减器、功率放大器和电源组成。该设备实现了各项技术指标要求,其中微波开关的驻波比在DC-1GHz时不大于1.3,在1GHz-18GHz时不大于1.5;衰减器的衰减量是40dB,精度是±3.5dB,驻波比不大于1.6;功率放大器的频率范围在0.9GHz～1.3GHz范围之内,输出功率不小于5W。该微波附件组合结合信号源、频谱仪、功率计及各类模拟器等射频仪器资源来实现射频测量通道的资源扩展、大功率信号的衰减调理、微波功率合成等功能。以满足被测试对象飞机系统中的微波射频系统、部件等微波信号性能测试的测试需求。     

Ka波段在线自检测MEMS微波功分器的设计与优化

提出了一种基于MEMS技术,由MEMS微波功分器和在线式MEMS微波功率传感器组成的在线自检测MEMS微波功分器,实现了MEMS微波功分器在Ka波段的实时在线功率自检测。MEMS微波功分器为T型功率等分功分器,由共面波导、圆形的不对称共面带线和空气桥构成,三个端口处分别放置三个相同的在线式MEMS微波功率传感器用于端口处信号功率的实时监测。该结构基于GaAs MMIC工艺,它可以与GaAs微波电路实现单片集成,通过ADS和HFSS软件的协同仿真,在中心频率34GHz处,回波损耗S11小于-30dB?插入损耗S21(S31)约为-4.7dB。在26GHz ~40GHz的频率范围内,S11约小于-15dB,隔离度S23小于-15dB。     

基于PDLC的可变光衰减器的研制

介绍了一种新型的低成本、小体积的的液晶可变光衰减器的设计与制作.该衰减器采用聚合物分散液晶材料,使其填充在经过耦合的带透明导电电极的两根单模光纤的间隙里,利用聚合物分散液晶在不同电场强度下引起的光的散射效应的变化,来实现对光路能量的可控连续衰减.采用体硅微细加工技术术成功地制作出了这种衰减器,并对器件进行了测试,结果表明:当传输的光波长为1550nm时,该衰减器的插入损耗为0.85dB;衰减的最大范围为0.85dB-14.21dB;驱动电压范围9V～57V.     

微波功分器的模拟与设计

介绍了功分器的原理,采用电容补偿法以减小功分器的尺寸,并利用奇偶模分析法推导了电容补偿的设计公式,利用HFSS软件模拟了电容补偿前后功分器的幅频特性和相频特性,电容补偿使得功分器的面积减小近一半,但也使得其幅频特性变差:在中心频率点10GHz处,S11均小于-32dB,但在9～11GHz的频率范围内,S11由低于-24dB变差为低于-14dB。     

X频段八波束接收组件的设计与实现

针对X频段多波束有源相控阵系统的高集成、小型化、多波束等需求,设计了一款高集成、小型化的瓦片式八波束接收组件,该组件基于多层印制板技术,纵向实现了众多有源器件以及八套波束合路网络高密度布局,实现了组件的高集成化;针对组件的八波束合成需求,基于Wilkinson功分器的形式设计了一款小型化的高效合路网络,在7.5-9 GHz范围内,其插入损耗小于13 dB,端口间隔离度小于-20 dB,输出驻波比小于1.2,通道间幅相一致性良好;为降低组件内部信号的传输损耗,对组件内部的垂直互联结构进行了建模分析,得到不同结构参数对其传输性能的影响,通过优化结构参数的方法实现信号的低损耗传输。在此基础上对组件进行了加工实现,经测试,在7.5-9 GHz范围内,组件输出通道增益大于18 dB,输出驻波比小于1.5,通道间相位一致性小于±5°,尺寸仅有80 mm × 80 mm × 7.66 mm。     

高阶∑△ADC中的抽取滤波器的设计

从电路实现和降低功耗的角度出发,优化并改进了梳状滤波器结构,同时设计了 FIR 补偿滤波器对其通带衰减进行补偿,通过合理的硬件电路安排来节省面积、提高速度,最终完成了高阶∑△ADC 中的抽取滤波器的设计。经过 Matlab 仿真,该滤波器阻带衰减为-65dB,通带纹波为±0.05dB,过渡带为0.454fs～0.583fs,经过 VerilogXL 和系统验证,该滤波器完全满足∑△ADC 的系统要求。     

RF-MEMS Capacitive Switches Fabricated Using Printed Circuit Processing Techniques

This paper presents radio frequency microelectromechanical systems (RF-MEMS) capacitive switches fabricated using printed circuit processing techniques. The key feature of this approach is the use of most commonly used flexible circuit film, Kapton E polyimide film, as the movable switch membrane. The physical dimensions of these switches are in the mesoscale range. For example, electrode area of a typical capacitive shunt switch on coplanar waveguide (CPW) is 2 mmtimes1 mm, respectively. A CPW shunt switch with insertion loss <0.4 dB and isolation >10 dB in the frequency range of 8 to 30 GHz is reported. K-band, Ku-band, and X-band high-isolation CPW shunt switches designed by inductive compensation of the switch down-position capacitance are also presented. Inductance compensation has been implemented by introducing inductive step-in-width junctions in the MEMS switch electrode. The K-band switch provides a maximum isolation value of 54 dB at 18 GHz. For the K-band switch, the insertion loss is less than 0.3-0.4 dB in the frequency range of 1-30 GHz and the isolation values are better than 20 dB in the frequency range of 12 to 30 GHz. The Ku-band switch provides a maximum isolation of 46 dB at 16.5 GHz. For the Ku-band switch, the insertion loss is less than 0.4-0.45 dB in the frequency range of 1-30 GHz and the isolation is greater than 20 dB in the frequency range of 12 to 22 GHz. The X-band switch provides a maximum isolation value of 32 dB at 10.6 GHz. The insertion loss is less than 0.25-0.3 dB in the frequency range of 1-18 GHz and the isolation is better than 20 dB in the frequency range of 8.5 to 13.5 GHz for the X-band switch. The measured typical pull-down voltage is in the range of 100-120 for this type of switches. These switches are uniquely suitable for monolithic integration with printed circuits and antennas on organic laminate substrates     

A Discrete Positioning Microactuator: Linearity Modeling and VOA Application

In this paper, we propose a discrete microactuator that can produce a desirable nonlinear displacement of the digital input. To develop a design algorithm with an arbitrary displacement function, we used curved comb electrodes that were electrically separated for each digital input. The algorithm was used to linearize the variable optical attenuator with a constant increment of 0.5 dB and an attenuation range of 32.6 dB. The experimental linearity was considerably improved down to 4.2% with an insertion loss of 1.1 dB     

A 4‐bit ultra‐wideband complementary metal‐oxide‐semiconductor attenuator with low root‐mean‐square amplitude error

This article presents the 4‐bit ultra‐wideband complementary metal‐oxide‐semiconductor (CMOS) attenuator in a standard 0.18‐μm CMOS process. This design adopts switched bridge‐T type topologies for each attenuation bit. Based on insertion losses and input P_1‐dB considerations, the circuit performances can be optimized by the proper bit ordering arrangement. Therefore, the bit ordering 0.5‐4‐2‐1 dB is employed in the 4‐bit attenuator. Moreover, series inductors are added between each bit to further improve the input and output return losses. Measured results demonstrate that the attenuation range of the circuit is 7.5 dB with 0.5 dB step and the root‐mean‐square (RMS) amplitude error is between 0.11 and 0.13 dB from 3.1 to 10.8 GHz. The differences between simulated and measured RMS amplitude errors are less than 0.2 dB, which demonstrates the good agreement and feasibility of the design concept. The measured input P_1‐dB is 15 dBm at 5 GHz and the chip area is 1.12 mm² including all testing pads.     

A compact wideband balun design using double‐sided parallel strip lines with over 9:1 bandwidth

A simplified miniaturized wideband balun design covering (0.38‐3.5 GHz) is presented. The broadband balun structure occupies a small area of 20.7 mm × 20.8 mm. The balun is designed using low loss double‐sided parallel strip lines and is comprised of a two‐stage Wilkinson divider followed by loading, symmetrically, the two output ports. One port with a phase inverter circuit; while a very similar but non‐inverting circuit is placed in the other port for loading‐balance compensation. To realize the balun's function, different smooth transitions have been employed and were accounted for. The fabricated balun circuit demonstrated phase and amplitude imbalance of less than ±5° and ± 0.4 dB, respectively, over the band.     

MEMS capacitive series switch fabricated using PCB technology

In this article, an RF MEMS capacitive series switch fabricated using printed circuit processing techniques is discussed. Design, modeling, fabrication, and characterization of the CPW series switch are presented. An example CPW series capacitive switch with insertion loss less than 0.5 dB in the frequency range of 13–18 GHz and isolation better than 10 dB up to 18 GHz is discussed. The switch provides a minimum insertion loss of about 0.1 dB at the self‐resonance frequency of 16 GHz and a maximum isolation of about 42 dB at 1 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Recessed ground microstrip line at 60 GHz and its application of band‐pass filter

The effect of finite‐size recessed ground on characteristic features of a microstrip transmission line is investigated and verified experimentally on alumina substrate of height 0.127 mm with ε_r = 9.8 at 60 GHz. A measured characteristic impedance of 238 Ω, effective dielectric constant of 3.09, and attenuation constant of 3.4 Np/m is achieved by using a recessed ground of dimensions (width × depth) 4.5 mm × 0.95 mm, below a 50‐Ω (on conventional ground plane) microstrip line. The effect of recessed ground on lumped equivalent circuit elements of microstrip line discontinuities including series‐gap, open‐end, and step discontinuities is also studied. To show the usefulness of recessed ground microstrip line, a prototype of fifth‐order Chebyshev‐type recessed ground end‐coupled band‐pass filter is designed and fabricated at 60 GHz. The filter exhibits measured insertion loss lower than 2.2 dB and return loss better than 13 dB over 3‐dB passband of 6% centered at 60 GHz. The measured results show good consistency with simulated results and confirm the usefulness of recessed ground plane microstrip line.     

A W‐band broadband power divider/combiner using two parallel antisymmetric tapered probes

In this article, a broadband microstrip‐to‐waveguide transition with antisymmetric tapered probe as well as a W‐band power divider/combiner using dual proposed antisymmetric tapered probes is presented. Because of tapered microstrip shapes and metallic steps, the proposed transition is proved to be broadband, efficient, and compact. The insertion loss of the transition sample is less than 0.56 dB between 75 GHz and 100 GHz. Under the assistance of the gradually changed waveguide and dual parallel tapered probes, the operating band of the power divider/combiner has been significantly improved, which is adequate to work in the whole W‐band. A back‐to‐back prototype of the divider/combiner is fabricated and measured. The measured insertion loss of the single divider/combiner is less than 0.29 dB between 90 GHz and 100 GHz, and agrees well with the simulations. Because the circuit size is smaller than 8.0 mm × 2.2 mm (Thanks to the excellent performance and compact size), the proposed design can find wide applications in miniaturized MCM/MMIC systems.