5 GHz low power frequency synthesiser with dual-modulus counter

A 5 GHz low power frequency synthesiser with a dual-modulus counter (DMC) was fabricated in 0.18 μm CMOS technology. The DMC allows to reduce the power consumption and to provide the functionality of the divider without a swallower counter. The settling time takes no more than 5 μs with an adaptive bandwidth topology. The measured phase noise is -87 dBc/Hz and -119 dBc/Hz at 10 kHz and 1 MHz offset frequencies, respectively. The reference spurs level is lower than -55 dBc at 10 MHz offset. The proposed synthesiser covers frequencies between 5.14 and 5.86 GHz in steps of 20 MHz and consumes 16.4 mW at 1.5 V supply voltage.     

Aperture-coupled asymmetrical c-shaped slot microstrip antenna for circular polarisation

A novel aperture-coupled, asymmetrical C-shaped slot, square microstrip antenna is proposed for circular polarisation (CP). A narrow and asymmetrical C-shaped slot, microstrip antenna is fed at the centre using an aperture coupling to obtain a CP operation. The compactness of the antenna is easily obtained by inserting a C-shaped slot. Wide CP radiation is achieved simply by making the C-shaped slot asymmetrical. With this antenna, the measured 3 dB AR bandwidth is around 3.3% and the 10 dB return loss bandwidth achieved is 16.0%. The overall antenna size is 0.48λo x 0.48λo x 0.092λo at 2.4 GHz. The proposed slot microstrip patch technology is useful to design compact, broadband, circularly polarised antennas and arrays.     

A 2.4-GHz Low-Power/Low-Voltage Wireless Plug-and-Play Module for EEG Applications

This paper presents a plug-and-play module for wireless electroencephalogram (EEG) applications. The wireless module is composed by an electrode, processing electronics, a radio-frequency (RF) transceiver, and an associated antenna. The RF transceiver was fabricated in the UMC RF 0.18 mum CMOS process, and operates in the 2.4-GHz ISM band. The receiver has a sensitivity of -60 dBm and a power consumption of 6.3 mW from a 1.8 V supply. The transmitter delivers an output power of 0 dBm with a power consumption of 11.2 mW, for a range of 10 m. It is also presented the electrical performance and comparison between different electrodes for EEG applications, namely sputtered titanium nitride (TiN) electrodes, standard sintered silver/silver chloride (Ag/AgCl) ring electrodes and sputtered iridium oxide (IrO₂) electrodes. The experimental results show a better performance of the sputtered IrO₂ electrodes compared with the standard sintered Ag/AgCl ring electrodes. These results promise a new opportunity for the application of a dry IrO₂ electrodes in wireless modules for using in a wearable EEG braincap. These wireless EEG modules will allow patients to wear a brain cap and maintain their mobility, while simultaneously having their electrical brain activity monitored.     

Low-power analogue phase interpolator based clock and data recovery with high-frequency tolerance

A low-power delay-locked loop (DLL)-based clock and data recovery (CDR) circuit with a high-frequency tolerance is presented. The design of DLL clock generator is based on an analytical approach to satisfy the jitter requirements of the system. Meanwhile, a novel analogue phase interpolator (PI) has been employed for fine delay adjustment of the recovered clock. Using a charge-pump-based PI, it is possible to simplify the control circuit considerably and hence reduce the system power consumption. To improve the frequency-tracking ability of the system, a frequency control loop is also added to the proposed CDR system. Designed in conventional 0.18 μm CMOS technology and operating in 10 Gbps data rate, the entire circuit consumes 52 mW.     

Temperature-stable voltage reference based on different threshold voltages of NMOS transistors

A temperature-stable voltage reference based on threshold voltages of enhancement and depletion NMOS transistors has been presented and implemented with a 0.5 μm DPDM CMOS technology. The problem of a fixed voltage reference value is avoided by different parameter design. A significant reduce of temperature dependence of mobility is also achieved. The chip?s area is 0.014 mm². The test results show that the operation supply voltage is from 2 to 5 V, the maximum supply current is 8.24 mA, and the average reference voltage is 765 mV with an average line regulation of ±0.187%/V. A typical temperature coefficient of 39.2 ppm/°C for a temperature range of 0?100°C is obtained. The power-supply rejection ratio, without any filtering capacitors, is 246 dB at 100 Hz and 232 dB at 1 MHz for the smallest supply voltage.     

Geometric centre tracking of tagged objects using a low power demodulation smart vision sensor

In this study, a modulated light detecting smart CMOS image sensor is presented. The design has the ability to sense asynchronous signals transmitted from electronic markers such as flashing light emitting diodes (LEDs) tagged on moving objects. The geometric centre of the detected region is returned as the output result. With the presented sensor, object localisation and position detection functions are simplified, performed at higher speeds in real time and power requirement is reduced. The sensor in-pixel processing filters out the background image data, detects the modulated marker regions and projects the extracted region on the two axes, while the geometric centre extraction units placed at each axis identify the coordinates assigned to the marker. The design presents less sensitivity to object texture compared with techniques based on edge extraction or binarisation. The sensor has been designed as a 64 x 64 pixel VLSI CMOS chip in the 0.35 μm standard CMOS technology and analysed in the presence of mismatches and noise. Issues such as sensor array scalability, speed and power dissipation are also examined in this study and features of the sensor are reported and compared with some previous designs.     

Compact carrier-injection photonic crystal switch for on-chip communications

Performances and metrics of an electro-optical wavelength switch in silicon?on- insulator technology using a 20 μm long photonic crystal directional coupler structure are theoretically studied using both electrical and finite difference time domain simulations. The possibility of photonic switching through carrier injection using a forward-biased PIN diode configuration is evaluated. It is shown that wavelength routing near λ=1550 nm with optical insertion loss of 1 dB and an electrical cut-off frequency of 60 MHz can be achieved with a bias voltage of 1 V and a dissipated electrical power of 700 μW. Integration of the device could be applied to active routing of light in silicon chips for the realisation of on-chip switching networks.     

Three-dimensional photoacoustic imaging using a two-dimensional CMUT array

In this paper, we describe using a 2-D array of capacitive micromachined ultrasonic transducers (CMUTs) to perform 3-D photoacoustic and acoustic imaging. A tunable optical parametric oscillator laser system that generates nanosecond laser pulses was used to induce the photoacoustic signals. To demonstrate the feasibility of the system, 2 different phantoms were imaged. The first phantom consisted of alternating black and transparent fishing lines of 180 μm and 150 μm diameter, respectively. The second phantom comprised polyethylene tubes, embedded in chicken breast tissue, filled with liquids such as the dye indocyanine green, pig blood, and a mixture of the 2. The tubes were embedded at a depth of 0.8 cm inside the tissue and were at an overall distance of 1.8 cm from the CMUT array. Two-dimensional cross-sectional slices and 3-D volume rendered images of pulse-echo data as well as photoacoustic data are presented. The profile and beamwidths of the fishing line are analyzed and compared with a numerical simulation carried out using the Field II ultrasound simulation software. We investigated using a large aperture (64 x 64 element array) to perform photoacoustic and acoustic imaging by mechanically scanning a smaller CMUT array (16 x 16 elements). Two-dimensional transducer arrays overcome many of the limitations of a mechanically scanned system and enable volumetric imaging. Advantages of CMUT technology for photoacoustic imaging include the ease of integration with electronics, ability to fabricate large, fully populated 2-D arrays with arbitrary geometries, wide-bandwidth arrays and high-frequency arrays. A CMUT based photoacoustic system is proposed as a viable alternative to a piezoelectric transducer based photoacoustic systems.     

Polymer microring resonators for high-sensitivity and wideband photoacoustic imaging

Polymer microring resonators have been exploited for high-sensitivity and wideband photoacoustic imaging. To demonstrate high-sensitivity ultrasound detection, highfrequency photoacoustic imaging of a 49-μm-diameter black bead at an imaging depth of 5 mm was imaged photoacoustically using a synthetic 2-D array with 249 elements and a low laser fluence of 0.35 mJ/cm². A bandpass filter with a center frequency of 28 MHz and a bandwidth of 16 MHz was applied to all element data but without signal averaging, and a signalto- noise ratio of 16.4 dB was obtained. A wideband detector response is essential for imaging reconstruction of multiscale objects, e.g., various sizes of tissues, by using a range of characteristic acoustic wavelengths. A simulation of photoacoustic tomography of beads shows that objects with their boundaries characteristic of high spatial frequencies and the inner structure primarily of low spatial frequency components can be faithfully reconstructed using such a detector. Photoacoustic tomography experiments of 49- and 301-μm-diameter beads were presented. A high resolution of 12.5 μm was obtained. The boundary of a 301-μm bead was imaged clearly. The results demonstrated that the high sensitivity and broadband response of polymer microring resonators have potential for high resolution and high-fidelity photoacoustic imaging.     

动目标射频仿真测试的应用研究与分析

详细阐述了阵列天线收发系统测试应用的动目标射频仿真模拟原理,以阵列天线收发系统的典型设备干涉仪接收机和相控阵干扰机的测试为例,介绍了动目标射频仿真应用测试系统的构建方案,同时对多个辐射元射频仿真模拟的近场效应误差对测试造成的影响进行仿真分析,得出阵列天线收发系统的射频仿真测试应用限制条件。     

Low-power baseband filter for zero-intermediate frequency digital video broadcasting terrestrial/handheld receivers

Digital video broadcasting terrestrial (DVB-T) is being adopted bymany countries all over theworld. Recently, DVB-H, a new standard compatible with DVB-T, has been proposed for handheld terminals, which demands low power consumption. In this study, a continuous-time filter for DVB-T/H receivers is presented. High linearity and lownoise are achieved by selecting a Gm-C filter topology implemented with a novel programmable transconductor based onMOS transistors in the triode region. The filter is tunable in a wide range, which makes it suitable for VLSI integration. The filter has been designed in a standard 0.5 μm CMOS technologywith a single 3.3 Vsupply voltage. Experimental results show an IM3 of 258 dB for a two tone experiment with 2 Vpp output signal centred at 2 MHz.     

A CMOS sensor optimized for laser spot-position detection

An optical sensor architecture optimized for flying-spot, triangulation-based, three-dimensional (3-D) laser scanners will be presented. The architecture implements a spot-position detection algorithm based on a two-step procedure that allows for improved dynamic range and readout speed. The sensor, which contains two linear arrays of pixels, analog readout channels, and digital signal preprocessing circuitry, has been fabricated in 0.6-/spl mu/m CMOS double-poly triple-metal technology and measures 8.17/spl times/5.67 mm/sup 2/. Pixel size and shape have been selected for reducing the effect of laser speckle and for the possibility of measuring color in a multiwavelength 3-D scanner. Electrooptical test results confirm the sensor behavior as expected from simulations on a dynamic range of 80 dB and exhibits a maximum speed of 50-k voxel/s.     

一种用于多标准接收机的宽带低噪声放大器

设计了一种应用于软件无线电接收机的300kHz～1.6GHz宽带低噪声放大器,适用于数字广播、数字电视和定位导航等系统.该放大器采用噪声抵消结构以降低输入匹配器件在输出端所产生的热噪声和闪烁噪声,能够同时实现输入阻抗匹配和噪声优化.对采用中芯国际(SMIC)0.18 μm RF CMOS工艺实现的芯片的测试结果表明,3dB带宽为300kHz～1.6GHz,最大增益S21为16.7dB,输入反射系数S11小于-7.4dB,最小噪声系数为2.3 dB,输入参考的1dB增益压缩点为-11.6dBm,功耗为14.4mW,芯片面积为0.49mm2.     

24-GHz ultra-wideband transmitter for vehicular short-range radar applications

This paper presents a 24-GHz transmitter for ultra-wideband short-range radar applications fabricated in a 0.13-μm SiGe:C BiCMOS technology. The circuit is composed of a frequency synthesiser, based on 24-GHz voltage-controlled oscillator in an N-integer phase-locked loop (PLL), a RF switch delivering a 0-dBm output power, and a tunable rectangular pulse generator, whose pulse width covers a range between 0.5 and 1.2 ns. The transmitter has been developed for a flip-chip bumping assembly on a module with an UWB antenna. Assuming a 10.5-dBi antenna gain, it is compliant with European Telecommunications Standards Institute (ETSI) transmission mask and is able to cover the main automotive applications addressing both a resolution better than 0.1 m and maximum unambiguous range of 15 m.     

Integrated optics magnetic sensor from 2 kHz to 9 GHz

A new type of integrated optical magnetic field sensor is presented in this paper. The proposed sensor consists of a Mach-Zehnder waveguide interferometer and a doubly loaded loop antenna. Such a structure can successfully avoid detection of the undesired electric field signal. The size of the sensor is 35 mm×6 mm×1 mm. The measurements show that the frequency response is from 2 kHz to 9 GHz, the dynamic range is 98 dB, and the minimum detectable magnetic field is 51.8 μA/m at 1 GHz. Therefore, this sensing system can be used in electromagnetic compatibility measurements.     

Distortion analysis of bootstrap switch using volterra series

Linear behaviour of bootstrap switches is of critical importance in low-voltage analogue circuits and understanding the major factors affecting the linearity helps design a better switch. This study presents a theoretical approach for evaluating the distortion of bootstrap switches in the frequency domain based on the Volterra series. Five major factors affecting the linearity of the bootstrap switch are examined. In order to obtain a general design guideline the analysis is done in two parts. First, the distortion because of the nonlinear I?V characteristic of the main transistor of the switch is considered. In the second part, the distortion because of sampling errors, such as clock feed-through and charge injection, are added to the analysis. The theoretical results are verified by circuit simulations in a 0.18 μm CMOS process, using HSpice.     

A Microbolometer Asynchronous Dynamic Vision Sensor for LWIR

In this paper, a novel event-based dynamic IR vision sensor is presented. The device combines an uncooled microbolometer array with biology-inspired (“neuromorphic”) readout circuitry to implement an asynchronous, “spiking” vision sensor for the 8–15 $mu{rm m}$ thermal infrared spectral range. The sensor's autonomous pixels independently respond to changes in thermal IR radiation and communicate detected variations in the form of asynchronous “address-events.” The 64 $times$ 64 pixel ROIC chip has been fabricated in a 0.35 $mu{rm m}$ 2P4M standard CMOS process, covers about $4times 4 {rm mm}^{2}$ of silicon area and consumes 8 mW of power. An amorphous silicon (a-Si) microbolometer array has been processed on top of the ROIC and contacted to the pixel circuits. We discuss the bolometer detector properties, describe the pixel circuits and the implemented sensor architecture, and show measurement results of the readout circuits. Subsequently, a DFT-based approach to the characterization of asynchronous, spiking sensor arrays is discussed and applied. Test results and analysis of sensitivity, bandwidth, and noise of the fabricated IR sensor prototype are presented.      

Dynamic properties of electrically p-n confined, epitaxially regrown 1.27 μm InGaAs single-mode vertical-cavity surface-emitting lasers

The dynamic performance including chirp measurements of 1.27 μm single-mode InGaAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) with a large gain-cavity offset is presented. The VCSELs are based on a novel p?n confinement structure with selective area epitaxial regrowth. A resonance frequency of 9.11 GHz, a slope efficiency of 0.25 W/A and an α-factor of 5.7 were measured. The modulation bandwidth is limited by electrical parasitics. Eye diagrams at 5 Gb/s with 7 dB extinction ratio and Q-factor around 5 were obtained. The results are compared with the performance of oxide-confined VCSELs with similar active layer and negative gain-cavity detuning.     

Frequency Modulated Continuous Wave System for Optical Fiber Intensity Sensors With Optical Amplification

We report on the use of erbium doped fiber (EDF) amplification to enhance a frequency modulated continuous wave (FMCW) technique for referencing optical intensity sensors located between two Bragg grating structures. The experiment combines the concept of FMCW with the spectrally selective mirror properties of Bragg gratings to interrogate with referencing properties intensity based sensors. The interrogation system without amplification yields a sensor resolution of around 0.078 dB. When the EDF amplifier is introduced into the experimental set up, the sensor sensitivity does not change, but the signal-to-noise ratio is improved, resulting into an enhanced resolution of 0.025 dB. We also obtain a remote sensing operation at a location of 50 km, showing the feasibility of this configuration to be used as a remote sensing application.     

低损耗As-S玻璃光纤的制备与应用研究

采用反复蒸馏提纯技术和开放式动态蒸馏相结合的工艺, 制备了高纯As-S玻璃, 基本消除了玻璃在2.9、4和6.3 μm处的杂质吸收。利用旋转法制备出壁厚均匀、表面质量优异的硫系玻璃套管。采用棒管法拉制出丝径50 μm, 芯径40 μm具有芯包结构的硫系玻璃光纤。拉制的As-S光纤机械性能和光学性能优异, 光纤丝径波动小于1%, 弯曲半径优于4 mm, 中红外波段损耗基线小于0.5 dB/m。制备出像元呈正方形排列, 出端规格64×9, 入端规格192×3, 用于线-面转换的红外传像束, 像束断丝率为2.7%。利用该异型传像束成功实现了长线阵的红外推扫成像。