A wireless and passive wafer cleanliness monitoring unit via electromagnetic coupling for semicondutcor/MEMS manufacturing facilities

This paper presents a wireless and passive chemical sensing system, in situ real time, via electromagnetic (EM) coupling, capable of monitoring wafer cleanliness during rinsing process at semiconductor/MEMS manufacturing facilities. A MEMS chemical sensor is embedded in a wafer-form transponder to evaluate the rinsing process in situ by measuring the conductivity of rinsing water inside micro-features formed by two interdigitated electrodes. All necessary power for the transponder is supplied from an external interrogator via the on-wafer transponder antenna. The modulated conductivity data is then emitted back from the transponder to the external interrogator in wireless and battery-free manner. The wireless system has been implemented on a 4-inch glass wafer to maintain the wafer form factor, not disturbing hydrodynamics of the rinsing process. The working distance of the system was measured to be about 25 cm, primarily limited by the coupled power to the transponder. Real time and in situ characterization of system was performed with three different control solutions: hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH). Detection uncertainty of the system was observed to be less than 2% (2 ppb for a 100 ppb solution).     

可调频手持发射器的倍频和音量控制电路设计

为了保证多媒体教学正常进行,避免无线话筒在使用时出现同频干扰,提出了手持发射器的可调频设计方案.设计选用IAP15L2K61S2单片机为微控制器,利用单片机内部定时器并结合外部锁相倍频电路,产生几种不同频率的脉冲,作为音频信号的载波;利用音频芯片M62429控制音频信号幅度调节无线话筒音量,实现音频信号的可调频传输和音量调节功能.测试结果表明,该设计方案可产生多种频率稳定的脉冲信号作为音频信号载波,并具有音量控制功能,有一定的工程价值和良好的应用前景.     

Third-order intermodulation in a micromechanical thermal mixer

A radio frequency (RF) micromechanical shell-type resonator with a resistive thermal actuator is shown to perform as a highly linear, broadband mixer and a high-quality factor post-translation (intermediate frequency) filter. The resistor is capable of frequency translation of RF carrier signals as high as 1.5 GHz to the intermediate frequency of 12.7 MHz. The thermal actuator allows electrical isolation between the input and output of the mixer-filter, dc bias independent mixing, and provides a 50-Ohm load to match the output of front-end electronics. High linearity is demonstrated in the mixer with a third-order input intercept point of +30 dBm for interferers spaced at a 50-kHz offset from the carrier frequency. A variant of the Duffing oscillator model and finite element modeling are used to analyze the origin of nonlinearities in the micromechanical system. [1503].     

Mobile wearable device for long term monitoring of vital signs

In long-term prevention and in rehabilitation of health of elderly people the recording of vital signs plays an important role. Especially the progress of rehabilitation can be deduced from the recording of an electrocardigram (ECG), blood pressure and body temperature. In this paper we present a wireless coupled recording device for long-term monitoring of these vital sign signals. We record the ECG, the blood pressure and the skin temperature and include a 3D-acceleration sensor for the determination of the movements during recording. To deal with motion artifacts in all recorded properties we use data fusion to reject or correct distorted vital sign signals.     

一种面向4G-LTE网络的丢包区分算法

无线网络中的丢包,一般认为是由拥塞或无线信道衰落造成的.在4G-LTE移动网络中,其传输特征的变化使得已有丢包区分算法并不适用.对此,提出了一种针对4G-LTE移动网络的丢包区分算法LDA-LTE.首先,基于LTE基站仿真器构建了真实可控的4G-LTE移动网络仿真测试平台;然后分别采集并分析了4G-LTE移动网络在拥塞和无线信道衰落条件下的传输特征;最后根据以上传输特征,提出了LDA-LTE丢包区分算法,实现了4G-LTE移动网络在拥塞和无线信道衰落同时发生场景中的丢包区分.实验结果证明,在4G-LTE移动网络中,由于网络传输特性与丢包特征的变化,使得传统的丢包区分算法并不适用,所提方法的区分结果准确度更高.     

易损/危险品物流监测智能微系统

一种基于数据采集、射频识别的信息采集系统,可以采集存储物流过程中超过阈值的振动、湿度以及温度,并记录对应的时间,然后通过无线通信向外发送记录的数据。本系统由三部分组成,包括基于加速度传感器、温/湿度传感器的数据采集模块、基于RFID的无线通信模块及报警模块。本系统不仅可为易损邮寄物品保驾护航,还可对流通中的危险品状态进行实时监测,能应用于多种恶劣环境,实时将报警消息发送至运输人员手中,及时发现问题,提高运输效率,有效地降低运输货品的破损率和危险品的事故率。     

0.2 mT Residual offset of CMOS integrated vertical Hall sensors

A residual offset lower than 0.2 mT is obtained with a CMOS integrated vertical Hall (VH)-sensor microsystem. Instead of the conventional design with five contacts in the sensor active area, we apply a layout with only four contacts. This design shows a higher effectiveness for the offset reduction by the spinning current (SC) method, because of the symmetrical current flow for the two different biasing phases. Furthermore, to obtain very low offsets, coupled sensors are integrated with the spinning current electronics in the final microsystem. A sensitivity up to S_v=0.025 V/VT is achieved for these sensors without any additional technology step. The measured output noise level of the integrated microsystem (1.9 μT/ ) is in the usual range of commercial integrated Hall-sensors. Our new developments open the way to the realization of compact, low-cost angular sensors with 10 bit resolution.     

A Multichannel Sinusoidal Model Applied to Spot Microphone Signals for Immersive Audio

In this paper, a multichannel version of the sinusoids plus noise model (also known as deterministic plus stochastic decomposition) is proposed and applied to spot microphone signals of a music recording. These are the recordings captured by the various microphones placed in a venue, before the mixing process produces the final multichannel audio mix. Coding these microphone signals makes them available to the decoder, allowing for interactive audio reproduction which is a necessary component in immersive audio applications. The proposed model uses a single reference audio signal in order to derive a noise signal per spot microphone. This noise signal can significantly enhance the sinusoidal representation of the corresponding spot signal. The reference can be one of the spot signals or a downmix, depending on the application. Thus, for a collection of multiple spot signals, only the reference is fully encoded (e.g., as an MP3 monophonic signal). For the remaining spot signals, their sinusoidal parameters and corresponding noise spectral envelopes are retained and coded, resulting in bitrates for this side information in the order of 15 kb/s for perceptual performance above the 4.0 grade on the mean opinion score (MOS) scale.      

A top-down design methodology of MEMS varactor for RF applications based on a substrate-induced capacitive model

Due to their excellent quality factor in microwave frequency range, microelectromechanical (MEMS) varactors are an attractive choice for wireless communication engineers for building high performance telecommunication circuits. Significant progress in the technology of MEMS varactor has been reported over the past few years; however a comprehensive design methodology for the varactors based on some performance specifications is not reported. Also, it has been found that for the varactors fabricated with multi user processes (MUMPs), the measured capacitance deviates widely from the predicted value. In this work, it has been shown that a substrate-induced capacitance can change the expected capacitance of the varactor widely and can justify the deviation of the measured values to a good degree of accuracy. Here, a quantitative account of this difference has been presented. The capacitance profile of the varactor fabricated in PolyMUMPs process has been measured and the results show good agreement with the design values; thus indicating a clear influence of substrate induced capacitance on the varactor. Finally, a systematic design methodology of the varactor for a voltage controlled oscillator (VCO) application has been given.

     

A top-down design methodology of MEMS varactor for RF applications based on a substrate-induced capacitive model

Due to their excellent quality factor in microwave frequency range, microelectromechanical (MEMS) varactors are an attractive choice for wireless communication engineers for building high performance telecommunication circuits. Significant progress in the technology of MEMS varactor has been reported over the past few years; however a comprehensive design methodology for the varactors based on some performance specifications is not reported. Also, it has been found that for the varactors fabricated with multi user processes (MUMPs), the measured capacitance deviates widely from the predicted value. In this work, it has been shown that a substrate-induced capacitance can change the expected capacitance of the varactor widely and can justify the deviation of the measured values to a good degree of accuracy. Here, a quantitative account of this difference has been presented. The capacitance profile of the varactor fabricated in PolyMUMPs process has been measured and the results show good agreement with the design values; thus indicating a clear influence of substrate induced capacitance on the varactor. Finally, a systematic design methodology of the varactor for a voltage controlled oscillator (VCO) application has been given.     

无线传感器网络的安全机制

近年来，随着微电子技术和无线通信技术的进步，推动了低功耗、低价格、多功能传感器的快速发展，进而也促进了无线传感器网络的发展．无线传感器网络在军事、医疗、商业等多个领域均有广阔的应用市场．针对无线传感器网络的特点，本文主要阐述它在通信过程中存在的安全威胁、分析它的安全需求和采取的安全机制，确保无线通信的安全．     

Heterodyne mixing and polarization diversity techniques in radio over fiber system with high sensitivity and dispersion tolerance

We propose and experimentally demonstrate the heterodyne mixing and polarization diversity tech- niques in radio over fiber (ROF) systems with the advantages of high sensitivity and dispersion endurance. The generation of 2.5 Gb/s optical DPSK and PSK signals, fiber propagation and wireless transmission over 15 GHz subcarrier are illustrated with very low sensitivity of -26 and -32 dBm, respectively. Moreover, based on the wireless polarization diversity techniques, we successfully performed the t...     

A study on the novel micromixer with chaotic flows

This paper presents the novel micro mixer with chaotic flow using coupling between Lorentz force and the moving force of the electric charge in an electric field. Rapid mixing is essential for μ-TAS technology, but is often difficult to achieve it at low Reynolds numbers in micro-systems. Although it is effective to mix with a stirrer for rapid mixing in a general macro-system, it is very difficult to fabricate it in a microsystem. Because the chaotic flow plays a role as a stirrer in a mixing chamber, the novel mixer is expected to mix more rapidly than existing micro mixers. The mixer not only has a simple structure compared with existing ones but also is able to achieve high mixing efficiency in spite of low power consumption. In order to estimate the efficiency for each mixer, the analytical expression and the computer simulations are performed. The results about the flow directions and the experimental results with mixing visualization are presented. Through the comparison with the mixing experiment using the diffusion process, we confirm that the proposed mixer with a simpler structure is able to achieve higher mixing efficiency.     

Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

In this paper, a 4.2–5.4 GHz, ?Gm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 μm SiGe BiCMOS process that includes high‐speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post‐layout simulation results, phase noise is ?110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and ?113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation‐mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm² on Si substrate, including DC and RF pads. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

基于DSP的EASI十二导联多功能Holter系统

一种以数字信号处理器(DSP)为核心,具有实时检测、无线传输和24小时心电数据连续记录功能的多功能Holter系统。在该系统中,通过EASI导联系统模块采集心电信号,然后采用小波变换算法对心电信号进行实时特征提取,并将心电数据存入MicroSD卡实现24小时心电数据记录;或者通过Zigbee无线传输模块将心电数据传输到电脑进行远程实时监测及十二导联心电数据的推导。     

A balanced dual‐band bandpass filter with independently tunable differential‐mode frequencies

A balanced dual‐band bandpass filter (BPF) with independently tunable differential‐mode (DM) frequencies is proposed in this letter. The proposed BPF is composed of complementary split‐ring resonators (CSRRs) etched on the ground and varactors loaded on the resonators. A balanced stepped‐impedance microstrip‐slotline transition structure is introduced to transfer the DM signals successfully and block the common‐mode (CM) signals transmission. Good DM transmission and CM suppression can be achieved. Moreover, by changing the reverse bias voltages of the varactors loaded on coupling CSRRs, two DM resonant frequencies of the proposed balanced BPF can be tuned independently. To verify the feasibility of the design method, a balanced BPF with DM frequency ranging from 0.80 GHz to 1.12 GHz and 1.55 GHz to 2.05 GHz is fabricated and measured. Good agreement between the simulation and measurement results demonstrate the validity of the design.     

Intra-body data transmission for the personal area network

Intra-body communication is a wireless means of exchanging information within a personal area network (PAN) between wearable electronic sensors and devices. The feasibility of intra-body communication is confirmed through several experiments on signal propagation within the human body, and a human phantom is designed and used to obtain reproducible results over repeated experiments. Based on the results of these experiments, a prototype transmission system is constructed using aluminum electrodes powered by 3 V DC and operating in the 10.7 MHz frequency modulation (FM) band. This prototype is demonstrated to be capable of transmitting analog signals through the human subjects in the presence of external noise. Digital data transmission at 9600 bps is also achieved using newly fabricated 10.7 MHz frequency shift keying (FSK) transmitter and receiver devices. The carrier frequency of 10.7 MHz is the intermediate frequency of FM radio receivers, meaning that the proposed system can make use of a wide selection of inexpensive, commercial radio frequency devices.     

无线便携式动物脑电遥测记录系统

开发出一套无线便携式动物脑电遥测系统。采集的数据经过放大、滤波后调制发射,接收器接收到无线信号后进行解调并通过串口打印显示出电压信号。实验中将测量电极植入大鼠颅骨内,并将信号采集发射器背负在大鼠身上,分别记录大鼠睡眠、清醒和癫痫脑电波形。实验结果表明该系统,复杂环境下发射器的发射距离达到20 m,可以稳定工作8 h,且具有体积小、功耗低、精度高等特点,适用于大鼠脑电遥测实验。     

CAD oriented frequency,temperature, and DC bias dependent small‐signal,scalable circuit model of parallel‐plate paraelectric varactors

Simple, CAD compatible small‐signal scalable circuit model for the thin film parallel‐plate ferroelectric varactors is reported. It is based on the measured permittivity and loss tangent of the ferroelectric films along with the fundamental theoretical relationships of ferroelectrics in paraelectric phase. The model makes use of the measured DC field (voltage) at the inflection point of the C‐V curve where the nonlinearity (dC/dV) and the tunability are maximum. Both the capacitance and the equivalent loss resistance (dielectric losses) in the ferroelectric film take into account the low permittivity layers at the boundaries of the nano‐columns of the film. The frequency dependent losses in the top and bottom plates of the varactors and the parasitic inductance of the plates are also taken into account. The model is valid for ferroelectric films having columnar structure. It is useful in wide temperature, DC field, and frequency ranges. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

基于微控制器的钻杆扭矩测量及其超声-蓝牙分级无线传输系统

为实时测量狭窄金属钻杆钻头的扭矩信息,基于微控制器设计了钻杆底部的扭矩数据采集终端,实现扭矩信号数字化并将数据OOK调制于超声波,利用超声波实现钻杆内的数据无线传输,解决了钻杆内电磁波衰减严重的问题。在钻杆顶部设置数据接收终端,接收超声信号并通过蓝牙链路将数据无线发送至上位机。上位PC机通过蓝牙适配器无线接收超声信号并解调恢复扭矩数据。这种联合超声-蓝牙的分级无线技术为狭窄金属屏蔽管内的无线数据传输提供了一种新的思路。