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。     

一种改进型毫米波开槽波导空间功率分配合成网络

研究了一种改进型毫米波开槽波导空间功率分配合成网络。该功率分配/合成结构具有合成效率高且合成效率基本不受合成路数的限制、尺寸小、设计过程灵活和容易散热等特点。在详细阐述了其原理及设计过程的基础上,设计了一个中心频率为38GHz的Ka频段末端的功率合成器。仿真结果显示此种结构回波损耗小于-12dB的带宽达2.3GHz,相对中心频率带宽约为6%,且插入损耗小于0.3dB,可见具有极低的插入损耗和较低的回波损耗,从而验证了此种结构的可行性。     

面向5G高隔离度4单元MIMO手机天线设计

设计了一个4单元高隔离度手机天线,由4个辐射单元组成,辐射单元分别位于天线的4个角落。对天线辐射单元进行分析测试,测量天线辐射单元工作频段为3.43 GHz～3.86 GHz,覆盖5G移动通信测试频段。MIMO天线工作频段在端口回波损耗小于-10 dB阻抗带宽条件下,工作频段为3.45 GHz～3.64 GHz;在端口回波损耗小于-6 dB阻抗带宽条件下,天线工作频段为3.23 GHz～3.96 GHz。新设计的圆形开槽结构能减少天线和电子元器件耦合,并且天线具有良好的全向性和辐射特性。MIMO天线在3.2 GHz～4 GHz频率内,天线辐射效率为65%～73.4%。仿真表明,脑部辐射SAR(Specific Absorption Rate)参数小于1.6 W/kg,天线对人体影响较低。     

宽频带缝隙馈电双层贴片微带天线设计

采用矩形谐振缝隙耦合馈电的方式,在辐射贴片的上方引入寄生矩形谐振器,地板下方四分之一波长处放置反射面,两辐射贴片之间使用多层低介电常数的泡沫介质基板,设计了一款宽频带微带天线。该天线不仅频带宽,后向辐射小,而且结构简单,便于阵列集成。仿真结果表明:在电压驻波比(VSWR)小于等于2时,该天线的阻抗带宽度达到了中心频率的58.42%;在5.12~8.98 GHz的频率范围内,天线的增益大于7.1 dB,回波损耗小于-10 dB。     

多应用环境下新型微带偶极子天线设计与优化

传统偶极子天线结构存在偶极子臂细、安全性低、天线走线占用空间大、增益特性差等问题,提出多应用环境下螺旋形印刷微带偶极子天线设计与优化方法。初始化微带偶极子天线工作结构,设计加粗偶极子臂的螺旋形印刷天线,减小天线走线占用空间。设计振子方向、振子阻抗特性,推导出最优结构参数。实验证明可知,在330MHZ-332MHZ的有效范围内,驻波比小于1.30dB ,在331.5MHZ-334.9MHZ有效范围内,回波损耗小于-10dB,其方向对称性较好,天线输入端驻波比与回波损耗较为理想,该天线具有较好特性。     

10-26GHz CMOS六位数控衰减器设计与实现

为了使衰减器更好的适应相控阵系统对高集成度波束赋形电路的应用需求。基于55nm CMOS工艺,设计了一款具有低插入损耗、低附加相移特性的六位数控衰减器,该数控衰减器采用桥T和π型衰减结构级联而成,在10-26 GHz频率范围内实现步进为0.5dB、动态范围为0-31.5 dB的信号幅度衰减。为减小插入损耗,NMOS开关采用悬浮栅和悬浮衬底连接方式,同时采用了电容补偿网络和电感补偿以有效降低附加相移。仿真结果表明,在10-26GHz的频带范围内,该数控衰减器的插入损耗小于-7dB,输入/输出回波小于-10dB,附加相移小于±3°,所有衰减态的衰减误差均方根小于0.8dB,芯片的核心电路面积为0.36 mm×0.16 mm。     

基于两种谐振器的微型化毫米波LTCC滤波器设计

利用两种新型谐振器设计多层毫米波低温共烧陶瓷(LTCC)滤波器,其一是双环谐振器,另一是分形缺陷梯形谐振器.使用这两种谐振器设计的LTCC滤波器都采用带线结构,整个体积为5.5 inm×2.5mm x0.6mm,利用全波分析软件优化设计并加工出两种结构的滤波器,双环谐振结构滤波器的中心频率为31.5GHz,相对带宽为10.0%,带内插入损耗和回波损耗分别为1.2,11.4dB.分形梯形谐振腔滤波器具有较宽的频带,带宽为30.1-39.20GHz,相对带宽为26.3%.带内插入损耗小于1.9dB,回波损耗小于11.2dB.测试结果与仿真分析数据基本一致,说明方案可行有效,所设计滤波器可以满足毫米波通讯系统的要求.     

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。     

基于铣削式加工的140 GHz矩形波导带通滤波器

利用现代计算机数控机床（Computer Numerical Control,CNC）铣削技术实现了中心频率为140 GHz的矩形波导带通滤波器。基于电磁仿真软件HFSS对该滤波器进行了优化设计和容差分析。采用CNC铣削技术完成了该滤波器的加工制备。测试结果与仿真结果吻合良好，表明该滤波器具备优越的性能：其中心频率为140.2 GHz、3 dB相对带宽为10.1%，插入损耗小于0.5 dB，带内回波损耗优于25 dB，距中心频率±20 GHz处带外抑制大于30 dB。该结果进一步验证了利用CNC铣削技术加工140 GHz波段滤波器的可行性。     

S波段微带均衡器的设计与实现

设计了一种用于低噪声放大器后端的微带增益均衡器,通过对其结构进行理论分析、设计、仿真及加工调试,完全实现了所需的目标幅频曲线,改善了输出增益平坦度。根据测试结果,该微带均衡器工作于2 GHz-3 GHz频带内的幅度在2 GHz频点最大衰减3.5 dB,3 GHz频点最小衰减0.5dB,并随频率呈递增特性,且输入输出回波损耗超过14 dB。     

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。     

一种新型MEMS微波功率传感器的理论模型与优化设计

提出了一种新型的MEMS微波功率传感器.与传统的结构相比,新结构具有测量误差小、设计简单、使用方便等显著优点.然后在全面考虑了热传导、热对流、热辐射三种传热机制的基础上,对传感器的主要部分即热电堆建立了热模型,进而导出了灵敏度、时间常数、噪声的理论解析式.最后根据拉格朗日乘数法原理,以给定的时间常数和噪声大小为约束条件,求得灵敏度达最大时热偶长度和串联数目的最佳值.     

A compact omnidirectional dual‐circinal rectenna for 2.45 GHz wireless power transfer

A compact dual‐circinal rectenna with omnidirectional characteristic is designed for microwave wireless power transmission at 2.45 GHz. A novel dual‐circinal receiving antenna with the reflection coefficient of ?32.5 dB is proposed which is formed by expanding folded curves. By designing an impedance matching network with a 60 ° radial stub and a single stub, a rectifier is presented with the maximum efficiency of 55.6 % and the output dc voltage of 1.19 V under the input power of 0 dBm. Simulation and measurements have been carried out for the antenna and the rectifier. The measured results agree well with the simulated value. The results of rectenna experiment show that the maximum conversion efficiency is 51% at 2.45 GHz when the input power is 0 dBm. The proposed rectenna has the characteristics of compact size and omnidirectional harvesting which are advantageous in RF energy harvesting applications.     

A Micromachined Inline-Type Wideband Microwave Power Sensor Based on GaAs MMIC Technology

Wideband 8–12-GHz inline-type microwave power sensors that are based on measuring the microwave power coupled from the coplanar waveguide line by a microelectromechanical systems membrane are presented. In this method, the signal is available during the power detection. In order to obtain the low reflection losses and insertion losses, as well as the wideband response of the power sensor, an impedance match structure and a compensating capacitance are proposed. The fabrication of the power sensor is compatible with the GaAs monolithic microwave integrated circuit (MMIC) process. The experimental results show that the sensor has reflection losses better than 20 dB and insertion losses less than 0.45 dB up to 12 GHz. A sensitivity of more than 30 $muhbox{V/mW}$ and a resolution of 0.2 mW are obtained at the 10-GHz frequency.$hfill$[2008-0219]      

一种应用于微波探测的双频天线的设计

为增加火灾探测天线频带范围,基于微带贴片天线,采用凹槽加载技术,设计了中心频率在Ku(12.4～18.0 GHz)波段的双频微带单元天线.利用HFSS软件对其建模、仿真及优化,结果表明,该单元天线在14.8 GHz和16.1 GHz时回波损失达到最小值,且回波损失小于-10 dB的带宽分别为600MHz和390 MHz.利用该单元天线,进而设计了一款2×2阵列天线,实测结果表明:该阵列天线具有很好的双频谐振特性,在14.3～14.9 GHz和15.7 ～16.1 GHz频带内既保留了原单元天线好的回波损耗特性,又提高了增益,使两个频段最大增益分别达到13.7 dBi和11.3 dBi.     

A novel wideband bandpass filter based on CSRR‐loaded substrate integrated folded waveguide

A novel wideband bandpass filter based on folded substrate integrated waveguide (FSIW) is presented in the article. Five square complementary split‐ring resonators (CSRRs) are etched in the middle layer of the FSIW. By adjusting the physical size of the CSRR structure, the resonant frequency of the CSRRs can be tuned at the same time and the stopband performance can be changed. As transverse electromagnetic (TEM) mode can be transmitted in the stripline, FSIW excited by stripline shows wider passband than that excited by microstrip line directly. To achieve perfect impedance matching, two microstrip lines to stripline transitions are added in two ports of the filter. The proposed bandpass filter exhibits compact size, high selectivity, good stopband rejection, lower radiation loss, and wideband performances. The measured results show that the fractional bandwidth of the filter is about 35.5%. The measured return loss is better than 15 dB from 4.84 GHz to 6.90 GHz, and the insertion loss is less than 1.2 dB. The comparison between the simulated results and the measured ones validate the possibility of the technology that combines the FSIW and CSRR.     

Dual‐band circularly polarized aperture‐coupled stack antenna with fractal patch for WLAN and WiMAX applications

This article presents a novel circular polarized (CP) aperture coupled stack antenna for wireless local area network and worldwide interoperability for microwave access dual‐band systems. The compact stack antenna consisted of square fractal patch, aperture couple, feed line and the perturbation. The square patch is constructed with the complementary Minkowski‐island‐based fractal geometry. By way of adjusting the relevant parameters, we can obtain the dual‐band responses at 3.5 and 5.25 GHz respectively. The CP of each band are presented. The measured 10 dB return loss impedance bandwidth are 270 MHz (7.5%) for 3.5 GHz band and 450 MHz (8.6%) for 5.25 GHz band. The 3 dB axial ratio bandwidths for each bands are 1.4 and 0.76%, the polarization of radiation patterns are both left‐hand CP, and the antenna power gain are 2.84–3.1 and 0.16–2.2, dBic respectively. The proposed antenna is successfully simulated and measured with frequency responses, radiation patterns and current distributions. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:130–138, 2014.     

Multiway wideband power dividers

In this article, we propose a new design methodology to broaden the bandwidth of a multiway Bagley power divider (BPD). Single‐frequency matching uniform quarter‐wave‐length microstrip lines in the conventional design are replaced with impedance‐varying transmission lines of broadband matching characteristics. The equivalent transmission line model is used for profiling impedance variations, which are governed by a truncated Fourier series. Such variations are determined by finding the optimum series coefficients that result in a wideband matching nature. The proposed technique leads to flexible spectrum allocation and matching level. Furthermore, the resulting structures are compact and planar. First, analytical results of three 3‐way BPDs of different fractional bandwidths are presented and discussed to validate the proposed approach. Then, two examples of 3‐ and 5‐way BPDs with bandwidths of 4–10 GHz and 5–9 GHz, respectively, are simulated, fabricated, and measured. Simulated and measured results are in a good agreement, with input port matching of below ?15 dB and ?12.5 dB for the 3‐ and 5‐way dividers, respectively, over the bands of interest. The obtained transmission parameters of the 3‐ and 5‐way dividers are ?4.77 ± 1 dB and ?7 ± 1 dB, respectively, over the design bands. The proposed wideband dividers find many applications in microwave front‐end circuitry, especially in only‐transmitting antenna subsystems, such as broad‐ and multicast communication links. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:730–738, 2015.     

3GHz～5GHz CMOS超宽带低噪声放大器设计

提出了一个低噪声、高线性的超宽带低噪声放大器(UWB LNA).电路由窄带PCSNIM LNA拓扑结构和并联低Q负载结构组成,采用TSMC 0.18 μm RFCMOS工艺,并在其输入输出端引入了高阶带通滤波器.仿真结果表明,在1.8V直流电压下LNA的功耗约为10.6 mW.在3 GHz～5 GHz 的超宽带频段内,...     

A micro compact coplanar power divider at X-band with finite-width ground plane based on GaAs MMIC technology

A micro coplanar Wilkinson power divider at X-band on GaAs substrate is presented in this paper. The proposed power divider introduces a size reduction method, and the length of the transmission line is reduced to λ/8 (at 10 GHz). Since the two segments of the two edge coupled quarter-wave asymmetric coplanar striplines (ACPSs) with finite-width ground plane are closed to each other, their characteristic parameters, such as characteristic impedance and attenuation coefficient, are obtained using the quasi-static conformal mapping technique (CMT) of coupled coplanar waveguide (CCPW) with finite-width ground plane. S-parameters for the power divider are deduced in the case of quasi-static TEM even–odd mode. The fabrication process is compatible with the GaAs MMIC process. The measured S-parameters are compared with the simulated results of HFSS v.11 and the calculated results of TEM even–odd analysis. Simulated results show that it has reflection loss less of 16.5 dB and insertion loss less of 3.6 dB. Measured results show that the divider has reflection loss less of 15.0 dB and insertion loss less of 3.5 dB. Compared with conventional Wilkinson power divider, the length of the power divider is shortened from 2,620 to 1,570 μm.