A novel self-aligned punchthrough implant: A simulation study

This paper presents a simulation study of a novel self-aligned punchthrough implant. The self-aligned dopant profile is achieved using a high-energy implant after polysilicon gate definition. The result is that in the channel region the implant peak is just below the surface and in the source-drain regions the implant peak is well below the junctions. Performance is increased through the reduction of parasitic junction capacitance. In this analysis an established 0.5 μm baseline technology shows a 100% reduction in the delay of a loaded inverter. Technologies with smaller or larger gate dimensions can benefit as well     

A novel array antenna for MSAT applications

The issue of reducing the cost of phased array vehicle antennas through the use of a lens feeding arrangement instead of phase shifters at each element is addressed. In particular, the economic viability of a mobile satellite system (MSAT) is largely dependent on the efficient use of the allocated scarce spectrum and orbit as well as the satellite power. The type of vehicle antenna used will play a critical role in achieving this efficiency. A standard design approach for an electronically steered array uses phase shifters at each element to provide beam steering. A method for reducing the required number of phase shifters by using an R-KR lens feed network is outlined. The authors briefly discuss the phase shifter approach to beam steering, examine various lens feed techniques, and describe the R-KR lens approach. The lens feed network architecture is examined, a computer model for simulation of the array is presented, and the results of analysis of a suggested design for the MSAT application are given. In addition, satellite acquisition and tracking considerations are investigated     

A novel systolic array structure for DCT

This paper presents a new algorithm for the implementation of discrete cosine transform (DCT), based on the idea of reformulating prime N-length DCT into two cyclic convolutions with exactly the same structure, which are implemented with a proposed fast cyclic convolution-based systolic array structure. The proposed algorithm can save (N-1)/2 multiplications and 2Nregisters, at the cost of only (N-1)/2 additions of those used in previous designs. The I/O is kept low because of the simple control complexity of the algorithm. Furthermore, this new algorithm preserves all the other benefits of very large-scale integration algorithms based on circular correlation or cyclic convolution, such as regular and simple structure.     

基于最佳配相控制的相控阵天线快速测量方法研究

为了解决相控阵天线快速测试问题,研究了一种相控阵天线测量的新方法.测试中相控阵天线和测试探头均不动,利用相控阵天线中各移相器的移相状态可控的特点,采用优化的配相快速算法,应用相控阵天线一些已知可信的信息,从而使测量具有较高的效率.给出了一个相控阵天线模型的仿真结果,以验证方法的正确性和有效性.     

A silicon-based, three-dimensional neural interface: manufacturingprocesses for an intracortical electrode array

A method has been developed for the manufacture of a "three-dimensional" electrode array geometry for chronic intracortical stimulation. This silicon based array consists of a 4.2 x 4.2 x 0.12 mm thick monocrystalline substrate, from which project 100 conductive, silicon needles sharpened to facilitate cortical penetration. Each needle is electrically isolated from the other needles, and is about 0.09 mm thick at its base and 1.5 mm long. The sharpened end of each needle is coated with platinum to facilitate charge transfer into neural tissue. The following manufacturing processes were used to create this array. 1) Thermomigration of 100 aluminum pads through an n-type silicon block. This creates trails of highly conductive p+ silicon isolated from each other by opposing pn junctions. 2) A combination of mechanical and chemical micromachining which creates individual penetrating needles of the p+ silicon trails. 3) Metal deposition to create active electrode areas and electrical contact pads. 4) Array encapsulation with polyimide. The geometrical, mechanical, and electrical properties of these arrays should make them well suited as interfaces to cortical tissue.     

A simulation study evaluating the performance of high-density electrode arrays on myocardial tissue

Multielectrode arrays used to detect cellular activation have become so dense (electrodes per square millimeter) as to jeopardize the basic assumptions of activation mapping; namely, that electrodes are points adequately separated as to not interfere with the tissue or each other. This paper directly tests these assumptions for high-density electrode arrays. Using a finite element model with modified Fitzhugh-Nagumo kinetics, we represent electrodes as isopotential surfaces of varying widths and spacing ratio (SR) (center-to-center spacing divided by electrode width). We examine the signal strength and ability of a single electrode to detect activation due to a passing wavefront. We find that high-density arrays do not cause significant wavefront curvature or alter activation timing in the underlying tissue. Relationships between signal strength, cross talk, and array design are explained by the interaction of the propagating wavefront and induced sources on the isopotential electrodes. Sensitivity analysis shows that these results may be generalized to a wide range of physiologically relevant designs and applications. We conclude that electrode array designs in which electrode spacing greatly exceeds electrode diameter are overly conservative and that arrays with a SR of less than 2.0 may perform successfully in electrophysiological studies.     

A novel current-scaling a-Si:H TFTs pixel electrode circuit for AM-OLEDs

Hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel electrode circuit with a function of current scaling is proposed for active-matrix organic light-emitting displays (AM-OLEDs). In contrast to the conventional current mirror pixel electrode circuit, in this circuit a high data-to-organic light-emitting device (OLED) current ratio can be achieved, without increasing the a-Si:H TFT size, by using a cascade structure of storage capacitors. Moreover, the proposed circuit can compensate for the variations of TFT threshold voltage. Simulation results, based on a-Si:H TFT and OLED experimental data, showed that a data-to-OLED current ratio larger than 10 and a fast pixel programming time can be accomplished with the proposed circuit.     

A novel hybrid of adaptive array and equalizer for mobilecommunications

The combination of the adaptive array and equalizer (AE) has been developed for suppressing the cochannel interference and the intersymbol interference (ISI) in mobile communications. In this paper, a novel hybrid of the adaptive array and equalizer (NHAE) system is proposed to combat the problems of insufficient degrees of freedom and mainbeam multipath interferers. The NHAE utilizes a modified training sequence to adjust the weight vector of the array that leads the array to cancel only the cochannel interferers. The ISI which is caused by the multipath interferers and the transmission system is removed by the equalizer following the array. Therefore, the array in the NHAE may need a fewer number of the elements than the conventional array which cancels both the cochannel interferers and multipath interferers. Besides, the presence of the mainbeam multipath interferers, which may seriously degrade the performance of the AE, has much less effect on the NHAE since it is suppressed by the equalizer instead of by the array. Simulation results are presented to demonstrate the merits of the NHAE     

Assessment of carbon nanotube array transistors: A three-dimensional quantum simulation

The noise characteristics of advanced silicon semiconductor devices fabricated with FinFET technology are investigated and modeled at the probe tip reference planes in the microwave frequency range. The transistor noise model is obtained by assigning an equivalent temperature to each resistor of the small signal equivalent circuit. These temperatures are selected to be equal to the room temperature with the exception of the temperature values of the intrinsic output, feedback, and substrate resistances, which are selected in order to reproduce accurately the 50 Ω noise factor measurements over a broadband frequency range going from 0.5 GHz up to 26.5 GHz. Accurate model simulations are obtained at such high frequencies, thanks to the inclusion of the noise temperature associated to the feedback and substrate resistances representing non-quasi-static effects which cannot be neglected in the investigated frequency range.     

System design for cooperative control of a microactuator array

A system design is presented with the aim of controlling many microactuators as autonomous distributed micromachines (ADMs). ADMs consist of many microcells which are smart enough to control their own motions and to cooperate with each other. A conveyance system in a plane is selected as an example of ADMs. We have developed a practical design of ADMs composed of many microcells integrated with actuators, sensors, and circuits which can be fabricated by IC-compatible micromachining. The behavior of the system is examined by simulation on a computer model. A fluidic microactuator array for a conveyor has also been fabricated and operated successfully     

A novel strategy for microcomputer-based control of a single-phaseoutput cycloconverter

A novel control algorithm using a time process chart that is capable of accurate control of cycloconverters is developed. This algorithm is obtained by making a straight-line approximation in a newly contrived phase plane. In spite of its rather simple procedures, this algorithm is capable of highly accurate control that is comparable to that of the conventional analog scheme. A six-pulse noncirculating current-type cycloconverter is controlled with a small-scale interface and a high-speed control program. Experimental results confirm the validity and usefulness of the proposed method. As far as the processing time is concerned, this method could be used to control a system with a larger pulse number, such as a 12 or 24-pulse system     

A novel polysilicon thin-film transistor with a p-n-p structuredgate electrode

We propose and fabricate a novel polycrystalline silicon thin-film transistor (poly-Si TFT) which exhibits the properties of an offset gated structure in the OFF state, while acting as a nonoffset structure in the ON state. The fabrication process is compatible with the conventional nonoffset poly-Si TFT's process and does not require any additional mask. Experimental results show that the leakage current of the new device is two orders of magnitude lower than that of the nonoffset gated device, while the ON current of the new device is almost identical to the nonoffset gated device. It is observed that the ON/OFF current ratio of the proposed poly-Si TFT is improved remarkably     

一种新型的FBG压力传感器数值模拟研究

提出一种基于金属圆筒式膜盒感受联杆传递到悬臂梁的组合式FBG压力传感机构,对其压力传感特性进行理论研究.利用双FBG(FBG1、FBG2)产生双反射峰实现温度压力同时区分测量,并且用有限元软件ANSYS进行了二维数值模拟实验.     

A novel hydrodynamic model for nanoscale devices simulation

This paper presents a novel scheme to incorporate quantum effect in classical hydrodynamic model. The scheme can be applied to multi-dimensional and transient conditions and no additional equations are required to solve quantum potential, so complexity of equations is drastically reduced. Simulation results show consistent with that of Monte Carlo simulation. This technology provides an efficient method for investigating quantum effect in small size semiconductor devices. A new guess method for hydrodynamics model has also been proposed in this paper and a 2D hydrodynamic simulator based on quantum correction and new initial guess method has been developed. The solution obtained from DD model gives a good initial guess of HD model. Its advantage is it can achieve convergence after a few iterations because initial guess is closed to final solution. Two-dimensional simulations have been carried out on a few nanoscale devices. The results have been compared with that of other initial guess methods and the significant differences have been found, especially in numerical stability.     

A simulation study of trellis-coded modulation for a satellite link

Trellis-coded modulation (TCM) offers a theoretical gain of more than 3 dB for an additive white Gaussian noise (AWGN) channel without an increase in signal bandwidth and without any alteration of the transmitted information rate. This article describes the simulation of TCM for an INTELSAT VI satellite link. It shows that the use of a simple four-state code can give a gain of up to 2.7 dB     

Experimental study of the control characteristics of a Schottky-trigger electrode on a Gunn device

To clarify the condition for the generation of a high-field domain in a Gunn device equipped with a Schottky-trigger electrode, a detailed experimental study was carried out. The difficulties in such experiments had so far rested in the accurate evaluation of the potential difference between the trigger electrode and the semiconductor thereunder, which we solved by an equivalent circuit representation of the device. Moreover, the accuracy of the evaluation of the potential difference was further increased by making use of the critical condition for the forward current through the Schottky barrier of the trigger electrode. From the experimental results it was made clear that a high-field domain is not necessarily generated when the field in the channel under the trigger electrode reaches the threshold field, but some form of the over-threshold-field state is established before a domain is generated. This shows that the device could be biased to higher anode voltages, leading to higher output voltages and wider operational margines than had earlier been expected.     

A novel tuning method for a neural control WDM demultiplexer

A new channel selection sequence using a neural control WDM demultiplexer is proposed in packet-switched WDM network. This demultiplexer achieves demultiplexing through an electrically controlled neuro-circuit, thereby achieving fast tuning. In the tuning experiment for optical signals at three different wavelengths, tuning is completed in approximately 20 /spl mu/s. The channel switching function is also examined by experimentation.     

Design and evaluation of a novel antenna array for azimuthalangle-of-arrival measurement

This paper describes a novel antenna array concept in which a “Y”-shaped distribution of elements is used to achieve uniform angle-of-arrival (AOA) measurement performance in azimuth, and a ground plane is employed to reduce the potential for confusion due to scattering from nearby structures and interference from low elevation angles. A simple method for field calibration of this array is also presented. A prototype has been built and tested in field conditions at 460 MHz. Using maximum likelihood estimation, the array is able to resolve single AOAs to within a few degrees and is able to identify discrete multipath from the same source. A shortcoming of the field-tested design is that it has poor gain along the horizon, due to edge diffraction from the ground plane. To control this diffraction, an elliptical rolled edge termination is proposed. It is shown that a rolled edge increases the horizon gain by 5 dB while maintaining high suppression at low elevations and maintaining a low physical profile     

A simultaneous multichannel monophasic action potential electrode array for in vivo epicardial repolarization mapping

While the recording of extracellular monophasic action potentials (MAPs) from single epicardial or endocardial sites has been performed for over a century, we are unaware of any previous successful attempt to record MAPs simultaneously from a large number of sites in vivo. We report here the design and validation of an array of MAP electrodes which records both depolarization and repolarization simultaneously at up to 16 epicardial sites in a square array on the heart in vivo. The array consists of 16 sintered Ag-AgCl electrodes mounted in a common housing with individual suspensions allowing each electrode to exert a controlled pressure on the epicardial surface. The electrodes are arranged in a square array, with each quadrant of four having an additional recessed sintered Ag-AgCl reference electrode at its center. A saline-soaked sponge establishes ionic contact between the reference electrodes and the tissue. The array was tested on six anesthetized open-chested pigs. Simultaneous diagnostic-quality MAP recordings were obtained from up to 13 out of 16 ventricular sites. Ventricular MAPs had amplitudes of 10-40 mV with uniform morphologies and stable baselines for up to 30 min. MAP duration at 90% repolarization was measured and shown to vary as expected with cycle length during sustained pacing. The relationship between MAP duration and effective refractory period was also confirmed. The ability of the array to detect local differences in repolarization was tested in two ways. Placement of the array straddling the atrioventricular (AV) junction yielded simultaneous atrial or ventricular recordings at corresponding sites during 1:1 and 2:1 AV conduction. Localized ischemia via constriction of a coronary artery branch resulted in shortening of the repolarization phase at the ischemic, but not the nonischemic, sites. In conclusion, these results indicate that the simultaneous multichannel MAP electrode array is a viable method for in vivo epicardial repolarization mapping. The array has the potential to be expanded to increase the number of sites and spatial resolution.     

Assessing the placement of a cochlear electrode array by multidimensional scaling

Correct placement of the electrode is crucial for cochlear implantation (CI) surgery. It determines the access to the auditory nerve and subsequent hearing performance. Here, we propose an objective measures tool that can partially verify the electrode position. The intracochlear spread of the electrical fields is measured and analyzed by means of multidimensional scaling resulting in an intuitive visual representation. The user can then detect major issues, such as electrode foldover or ossification. Other implantation issues, such as electrode migration into the scala vestibuli, may not significantly alter the electrical conduction pattern and remain undetected. Still, as the measurement is quick and readily available, it may be a valuable intraoperative verification tool.