BJ-320波导对称五端口测量网络设计

介绍了工作于26.4～40 GHz频带的对称五端口波导网络的设计方法.为了使五端口波导网络能较好地工作于六端口反射计中,要求各端口反射系数的绝对值小于0.2(| S11|≤0.2).这里结合了频移法、渐变线分割研究法和数值解法等理论对五端口波导测量网络进行设计.     

微波六端口反射计仿真设计

六端口反射计在微波阻抗与网络参量测量方面有着很重要的地位。该文介绍了一个工作于要求频段（9—10GHz）内的六端口反射计的设计方案，通过对反射计的S参数进行分析确立设计指标；依据这一指标，该文首先通过LSBRM方法确定波导网络的内半径及中心金属轴半径；进而采用频移法来确定渐变线的大端的高度；最后用渐变线分割的方法和数值积分的算法确定了波导渐变线的长度L，完成方案的设计；对设计好的反射计经测量检验，该反射计在9—10GHz频带内的最小衰减可达到-20dB，满足设计指标的要求。该文提供的方法，同样适用于其他频段内工作的反射计的设计，对相关科研工作人员具有一定的参考价值。     

安捷伦科技发布新型功能更强的经济型射频网络分析仪

本刊讯:2011年6月9日,北京??安捷伦科技公司(NYSE:A)日前宣布推出广受欢迎的ENA系列网络分析仪的最新产品--E5072A矢量网络分析仪。E5072A是双端口网络分析仪,测量频率从30 kHz至4.5 GHz或8.5 GHz,性能卓越,优于当前任何一类射频网络分析仪。它以增强的功能、可改变测量端口的配置结构、更宽输出信号功率范围来保证对器件指标的全     

一种通用的微波六端口反射计研究

在微波阻抗与网络参量测量方面,反射计应用举足轻重;在通过对反射计的S参数进行分析的基础上,介绍了一个六端口反射计的通用设计方案,并确立了设计指标;依据设计指标,利用LSBRM方法、频移法、渐变线分割的方法和数值积分等算法完成了六端口反射计的设计;最后通过实际的反射计测量检验验证其满足设计指标的要求.     

用于天线罩电厚度测量的小型微带六端口反射计

六端口反射计广泛用于高精度反射系数测量,若采用小型测量网络作为测量探头,它可用于天线罩电厚度的无损检测,本设计为一个用于此目的的六端口反射计,该反射计主要由微带对称五端口双环网络与多分支线微带定向耦合器组成,借助于Microwave Office软件对这两部分进行优化与仿真设计,实际电路测试结果表明,此微带六端口反射计在较宽的频带内具有高的测量精度,且由于体积小,可方便地用于天线罩电厚度测量.     

用于天线罩电厚度测量的小型微带入端口反射计

六端口反射计广泛用于高精度反射系数测量，若采用小型测量网络作为测量探头，它可用于天线罩电厚度的无损检测，本设计为一个用于此目的的六端口反射计，该反射计主要由微带对称五端口双环网络与多分支线微带定向耦合器组成，借助于Microwave Office软件对这两部分进行优化与仿真设计，实际电路测试结果表明，此微带六端口反射计在较宽的频带内具有高的测量精度，且由于体积小，可方便地用于天线罩电厚度测量。     

基于双魔T六端口反射计的自动化设计

根据六端口反射计工作原理，对基于双魔T的六端口测量系统进行自动化设计；通过放大器和A／O转换电路对输出端口的检波电压进行采集，根据相对功率法求解系统常数，完成系统的校正，然后接入待测负载，南三个状态下的系统常数和端口功率构建线性方程组，编程求解确定负载的反射系数，并画出状态圆对测量结果加以验证。试验结果表明，该系统不仅保证了反射系数的精度，而且测量效率得到了显著的提高。     

基于SOLT校准技术的S参数测量不确定度评定

目前,常用的S参数测量不确定度评定方法中均未考虑S参数相关性的问题,论文给出了一种2GHz~18GHz频率范围内S参数测量不确定度的评定方法,该方法从校准件的定义出发,基于SOLT校准技术对矢量网络分析仪进行自校准,将校准件引入的不确定度通过矢量网络分析仪传递给被测件(DUT),通过使用蒙特卡洛仿真的方法(MCM)得到矢量网络分析仪测量DUT S参数的测量不确定度,评定过程中考虑了相关性问题,提高了S参数测量不确定度的可靠性和合理性。     

基于 SOLT 校准技术的S参数测量不确定度评定磁

目前,常用的 S 参数测量不确定度评定方法中均未考虑 S 参数相关性的问题,论文给出了一种2GHz ～18GHz 频率范围内 S 参数测量不确定度的评定方法,该方法从校准件的定义出发,基于 SOLT 校准技术对矢量网络分析仪进行自校准,将校准件引入的不确定度通过矢量网络分析仪传递给被测件（DUT ）,通过使用蒙特卡洛仿真的方法（MCM ）得到矢量网络分析仪测量 DUT S 参数的测量不确定度,评定过程中考虑了相关性问题,提高了 S 参数测量不确定度的可靠性和合理性。     

FBAR传感器信号检测与处理电路研究

设计并制作了薄膜体声波谐振器(FBAR)的生化传感器信号检测与处理电路,该电路采用混频器,把高频信号混频到低频信号,降低了信号的处理难度,并以Cyclone FPGA为核心控制器,完成对采样数据的处理和存储,并实现了实时传输等功能。利用该电路对双工器进行了初步测试,结果表明,谐振频率与网络分析仪所测结果一致。     

薄膜体声波谐振器的结构参数优化分析

建立了微型薄膜体声波谐振器的等效电路模型,研究其整体频率响应特性.提出的等效电路模型考虑了氧化锌压电薄膜两端电极和作为支撑层的氮化硅薄膜对谐振器整体性能的影响,将它们作为传输线引入到等效电路当中.运用PSPICE软件研究了谐振器各结构层的尺寸参数对谐振器谐振频率、品质因数和有效机电耦合系数的影响,并讨论了使用不同材料的电极,谐振器品质因数的变化情况.基于以上分析,对谐振器的结构参数进行优化,获得薄膜体声波谐振器性能的提高.     

Highly sensitive mass sensor using film bulk acoustic resonator

Film bulk acoustic resonators (FBAR) have recently been adopted as alternatives to surface acoustic wave (SAW) in high frequency devices, due to their inherent advantages, such as low insertion loss, high power handling capability and small size. FBAR device can also be one of the standard components as mass sensor applications. FBAR sensors have high sensitivity, good linearity, low hysteresis and wide adaptability. In this study, a highly sensitive mass sensor using film bulk acoustic resonator was developed. The device structure of FBAR is simulated and designed by the Mason model, and fabricated using micro electromechanical systems (MEMS) processes. The fabricated FBAR sensor exhibits a resonant frequency of 2442.188 MHz, measured using an HP8720 network analyzer and a CASCADE probe station. Experimental results indicate that the mass loading effects agree with the simulated ones. Results of this study demonstrate that the sensitivity of the device can be achieved as high as 3654 Hz cm²/ng.     

Ladder‐lattice bulk acoustic wave filters: Concepts,design, and implementation

This article presents a study of ladder‐lattice bulk acoustic wave (BAW) filters. First, a review of BAW technology and filters topologies is addressed. Next, a mixed ladder‐lattice BAW filter for application on W‐CDMA reception front‐ends (2.11–2.17 GHz) is presented. An improved solidly mounted resonators (SMR) technology was used for the filter implementation. The filter synthesis methodology is briefly described. Layout guidelines are discussed enabling an optimized filter design. The filter on‐wafer measurement results are as follows: ?3.55 dB of insertion loss, ?8.7 dB of return loss, an isolation higher than ?47 dB at the transmission band (1.92–1.98 GHz) and an improved selectivity (?30 dB at 2.14 GHz ± 60 MHz). Therefore, we can observe that the mixed topology combines the advantages of ladder and lattice networks, having very steep responses and an improved isolation at undesired bands. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

基于薄膜体声波谐振器的免疫球蛋白传感器制备

研制了一种基于薄膜体声波谐振器（ FBAR）的生物免疫球蛋白传感器,该FBAR采用AlN作为压电层,3对Ti/W金属层作为布拉格声学反射层,工作频率为2.047 GHz,回波损耗为－32 dB。利用自组装膜法修饰顶部金电极敏感区域。测试了免疫球蛋白G抗体和抗原的特异性结合前后传感器的指标变化。结果得到传感器的Q值和灵敏度分别达到846,3.38 kHz·cm2/ng,远高于广泛使用的石英晶体微天平（ QCM）,具有广阔的应用前景。     

短路反射法测量复介电常数的研究

研究了基于波导六端口反射计系统的短路反射法测量介质材料复介电常数的测量原理,通过六端口反射计测量得到介质样品加载前后参考面的复反射系数,求得样品介质的相对介电常数和损耗正切。提出了一种新的求解复超越方程的数值解法,该方法以泰勒近似获取初值,通过梯度迭代得到最终结果,避免了复超越方程中无用多值的出现。实际测试结果表明,该方法可以快速单一地测得介质材料的相对介电常数,且精度较高。     

Design and fabrication of microfluidic devices integrated with an open‐ended MEMS probe for single‐cell impedance measurement

When an electrical current with a low frequency is applied to a cell, the current passes through the outside of the cell. Thus, impedance measurements at low frequencies cannot be used to determine the pathological change of the cellular organelle taking place inside the cell. However, increasing the frequency of the electrical current makes the capacitive impedance of the cell decrease, allowing the electrical current to flow through the cell. This study presents the design and fabrication of a microfluidic device integrated with a coplanar waveguide open-ended micro-electro-mechanical-systems (MEMS) probe for the impedance measurement of the single HeLa cell in frequencies between 1 MHz and 1 GHz. The device includes a poly-dimethlysiloxane (PDMS) cover with a microchannel and microstructures to capture the single HeLa cell and a conductor-backed CPW fabricated using a silicon chip and two printed circuit boards (PCB). The effects of the substrate on the characteristic impedance of the conductor-backed coplanar waveguide (CBCPW) structure were investigated under three conditions by utilizing a time-domain reflectometer (TDR). Finally, impedance measurements using the proposed device and a vector network analyzer (VNA) are demonstrated for de-ionized (DI) water, alcohol, PBS, and a single HeLa cell.     

A readout circuit for an intra-ocular pressure sensor

A readout circuit for a passive telemetric intra-ocular pressure (IOP) sensor is being developed. The intra-ocular sensor consists of a capacitive pressure sensor in parallel with a planar coil. This inductor–capacitor (LC) resonant circuit transduces the pressure into a shift of resonance frequency. A voltage controlled oscillator (VCO) is used to excite the sensor over a large frequency range (20–40 MHz), hereby detecting resonance of the internal sensor, and thus enabling the measurement of the intra-ocular pressure. This low power circuit is extremely compact, making it suitable for long-term ambulant patient monitoring. The circuit allows wireless readout of the smallest pressure transducers. Tests show promising results at mutual coil distances up to 7.5 mm.     

Electrical Frequency Tuning of Film Bulk Acoustic Resonator

This paper describes the design, fabrication, and measurement of an electrically tunable film bulk acoustic resonator (FBAR) that is formed by integrating FBAR with an electrostatic microelectromechanical systems actuator. Around 1.47% tuning of the series resonant frequency ( Deltaf cong 22.5 MHz) at 1.5 GHz is experimentally obtained with an electrostatic actuation voltage of 7 V. This is the highest frequency tuning reported for FBAR operating at above 1 GHz without any extra power consumption. Two integration approaches of FBAR and air-gap capacitor are presented and compared, in terms of fabrication process and Q factor. The approach that minimizes any possible energy loss in the acoustic wave propagation path shows a quality factor (160-304) significantly higher than the one having a capacitor right on top surface of the FBAR's piezoelectric film. Furthermore, we have characterized the electrical tuning of FBAR through piezoelectric stiffening due to an applied DC electric field and report a linear frequency shift of about -8 ppm/V at 3.4 GHz.