Study on signal transmission performance of microwave multi-chip modules interconnect via hole structure

Grounding is an important technology of microwave circuits. Soldering process can realize the grounding of microwave chip. However, the solder voids in soldering can make the reliability of grounding worse, deteriorating heat conduction performance and conductive properties, resulting in an error in signal transmission and significantly reduce the transmission performance of microwave signal. As the device operating frequency goes higher, solder voids can lead to serious signal integrity problems, for this reason, influence of different positions, sizes and number of void in soldering on signal transmission performance of microwave were investigated. The result shows that the void close to the feeding port has the greatest influence on the signal transmission performance, the signal transmission performance worsens with the volume of void enlarging, in addition, below the transmission line, with the increasing in number of voids, the signal transmission performance is deteriorated.

A neuron carries out its functions in networks receiving contacts from roughly 104 presynaptic neurons. Such a dense connectivity profile for a single neuron may give rise to enormous complex neuronal topologies, which might be very difficult to understand the underlying mechanisms of neurological functions and diseases. Extensive experimental data from neuroanatomical studies have uncovered that neural networks include some recurring topologies of microcircuits, known as network motifs which serve as characteristic building blocks of complex networks [1,2]. Therefore, it is widely assumed that a clear explanation on dynamical and functional features of these network motifs can be considered as the first step to understand large networks. Following this motivation, in this study, we investigate the Vibrational Resonance (VR) phenomenon in a triple-neuron feed-forward-loop (FFL) which is one of the most significant brain network motifs, shown in Figure ​Figure1.1. VR is a physical phenomenon found in nonlinear systems where a weak signal can be detected and processed by the system with the assistance of another high frequency signal. It is very similar to the well-known stochastic resonance phenomenon, where the role of noise is replaced in VR by a high frequency signal. In recent years, there exists a growing interest in applications of VR to neuroscience because two frequency signals are pervasive in neural systems, i.e. bursting neurons exhibit two widely different time scales, simultaneous arrival of vocal signals having distinct frequencies to auditory neurons. Due to the significance of its potential in neural signal processing, the VR phenomenon has already been studied with computational models of neurons and their networks [3,4]. However, a population of excitatory and inhibitory neurons has not been considered, yet. Here, we study the VR dynamics depending on whether the neurons in the FFL motifs are excitatory or inhibitory considering eight possible structural configurations of the considered microcircuit (Table ​(Table1).1). Such an approach provides us to test the functional influences of structural configuration on VR dynamics in neural populations. Figure 1 Schematic illustration of the considered feed-forward-loop motif. LF and HF refers to low and high frequency signals, respectively. Neuron 1 and 3 is considered as input and output neurons, respectively. Table 1 Eight possible FFL types. We found that the weak signal transmission in the network via the VR mechanism is possible depending on both the coupling strength between neurons and the network structure. For instance, when a weak coupling strength is present between connected neurons, weak signal injected to the input neuron can be transmitted to the output with only T8-FFL motif. In this case, signal transmission is impossible for other types of network motifs. For intermediate coupling strengths, signal transmission performance is high for all motifs and motif type does not change very much VR dynamics. Finally, for strong coupling strengths, the best VR performance is obtained with T1-FFL motif where all the neurons in the network are excitatory. We also clarify the mechanisms that underlies the differences in performance of network motifs.

Based on a comprehensive theoretical model of a recently proposed novel technique known as adaptively modulated optical orthogonal frequency-division multiplexing (AMOOFDM), investigations are undertaken into the impact of an analog-to-digital converter involved in the AMOOFDM modem on the transmission performance of AMOOFDM signals in unamplified intensity-modulation and direct-detection (IMDD) multimode-fiber (MMF)-based links. It is found that signal quantization and clipping effects are significant in determining the maximum achievable transmission performance of the AMOOFDM modem. A minimum quantization bit value of ten and optimum clipping ratio of 13 dB are identified, based on which, the transmission performance is maximized. It is shown that 40-Gb/s-over-220-m and 32-Gb/s-over-300-m IMDD-AMOOFDM signal transmission at 1550 nm with loss margins of about 15 dB is feasible in the installed worst case 62.5-mum MMF links having 3-dB effective bandwidths as small as 150 MHz middot km. Meanwhile, excellent performance, robustness to fiber types, and variation in launch conditions and signal bit rates is observed. In addition, discussions are presented of the potential of 100-Gb/s AMOOFDM signal transmission over installed MMF links

3-D integration technologies have been of increasing interest for compact and high-performance system integration and packaging. Through-silicon-via (TSV) is one of the key technologies to enable vertical connections for stacked ICs and silicon packages. In the recent years, the annular via and taped via geometries have been the focus for industry research institutes and has been demonstrated to have lower electrical resistance and better thermal stability. Different TSV physical structures such as cylindrical, tapered, annular are analyzed using the FEM based EM simulator HFSS in this study. In addition to the TSV shape impact on the performance of TSV signal transmission, the effect of substrate conductivity on the signal transmission is investigated in this study.

<div class="section abstract"><div class="htmlview paragraph">With the aim of improving engine performance, recent trend of fuel injection nozzle design followed by engineers and researchers is focusing on more efficient fuel break up, atomization, and fuel evaporation. Therefore, it is crucial to characterize the effect of nozzle geometric design on fuel internal flow dynamics and the consequent fuel-air mixture properties. In this study, the internal flow and spray characteristics generated by the practical multi-hole (10 holes) nozzles with different nozzle hole length and hole diameter were investigated in conjunction with a series of computational and experimental methods. Specifically, the Computational Fluid Dynamics (CFD) commercial code was used to predict the internal flow variation inside different nozzle configurations, and the high-speed video observation method was applied to visualize the spray evolution processes under non-evaporating conditions. Moreover, the Laser Absorption Scattering (LAS) method was implemented to explore the spray evaporation characteristics. The different nozzle internal flow properties summarized from the computational results could be used to give a comprehensive explanation for the mechanism behind the spray behaviors observed in the experiments. Furthermore, the nozzle geometrical design effect was correlated with the numerical and experimental results under the evaporating and non-evaporation conditions. It indicated that the hole geometry can alter the dynamic internal flow, liquid jet break up, spray propagation, and the ambient gas entrainment, simultaneously. Moreover, two of the most important factors, hole diameter and hole length, can exert different effect on the spray break up and evaporation process. For the current experiments, an appropriate ratio of nozzle hole length to diameter is found and suggested concerning the fuel break up and evaporating characteristics. When pursuing the optimum nozzle geometrical design, the effect of hole length and hole diameter should be considered from a comprehensive view.</div></div>

Shear performance and failure process of perfobond connector in steel-UHPC composite structures

HighlightsIME technology is combined with conductive PET and LSR polymer materials to preform Utah arrays for BCI.The effects of three key factors on the nodal displacement were analyzed using the Kriging model.The heat transfer during injection molding was further analyzed by PDEs in order to determine the parameters more accurately.The allowable variation range of the wire diameter is obtained by the relation between the wire diameter and the current.Injection molding is an efficient and precise manufacturing technology that is widely used in the production of plastic products. In recent years, injection molding technology has made significant progress, especially with the combination of in-mold electronics (IME) technology, which makes it possible to embed electronic components directly into the surface of a product. IME technology improves the integration and performance of a product by embedding conductive materials and functional components in the mold. Brain–computer interfaces (BCIs) are a rapidly growing field of research that aims to capture, analyze, and feedback brain signals by directly connecting the brain to external devices. The Utah array, a high-density microelectrode array, has been widely used for the recording and transmission of brain signals. However, the traditional fabrication method of the Utah array suffers from high cost and low integration, which limits its promotion in practical applications. The lines that receive EEG signals are one of the key parts of a brain–computer interface system. The optimization of injection molding parameters is particularly important in order to effectively embed these lines into thin films and to ensure the precise displacement of the line nodes and the stability of signal transmission during the injection molding process. In this study, a method based on the Kriging prediction model and sparse regression partial differential equations (PDEs) is proposed to optimize the key parameters in the injection molding process. This method can effectively predict and control the displacement of nodes in the film, ensure the stability and reliability of the line during the injection process, and improve the accuracy of EEG signal transmission and system performance. The optimal injection parameters were finally obtained: a holding pressure of 525 MPa, a holding time of 50 s, and a melting temperature of 285 °C. Under this condition, the average node displacement of UA was reduced from the initial 0.19 mm to 0.89 µm, with an optimization rate of 95.32%.

Preparation of digital aggregate from γ-C2S carbonation for life-cycle management and traceability of concrete: Mechanical, signal transmission, and microstructural performance

Nowadays, in order to improve the quality of signal transmission and reduce the signal attenuation and noise interference, the transmission digital baseband signal modulation become mainstream in today's signal transmission. For the digital baseband signal transmission performance of research helps us to understand the process of digital signal transmission. Firstly, using shift registers to produce m sequence, used to simulate the data signal and the pseudo random noise signal. Then, to design a low pass filter, used to simulate the channel. Data signal transmission in the channel was carried with additive random noise interference, we can measure signal interference by observing eye pattern at the receiving terminal. If to Manchester encoding of data signal, the receiver decoding output data signal can be extracted using the synchronous clock circuit to get the clock signal to synchronize, and display the eye pattern, which is used to evaluate the performance of the transmission system. And we put forward the optimization scheme of the digital baseband signal transmission performance through the research.

A next-generation satellite broadcasting system using the 21-GHz band (21.4–22.2 GHz) allocated for satellite broadcasting is expected to provide large-capacity advanced broadcasting services. To use the 21-GHz band, higher output power to compensate for rain attenuation and protection of the radio astronomy band are required. We report the design and prototype of a 300-MHz class wide-band modulator-demodulator (modem) for use with the 21-GHz band satellite broadcasting system. The prototype modem is evaluated for signal characteristics and transmission performance with intermediate frequency connection.

An aseptic packaging should, in principle, provide protection against any kind of bacteriological penetration. This means that any microholes present in the packaging walls or seams must not have a diameter greater than about 0.5μm In practice, the tolerance limit probably lies higher owing to the fact that the length and surface properties of the holes obstruct penetration. The time factor, the concentration of microbes and their growth possibilities in the vicinity of the hole are of course also of crucial importance as to what practical tolerance limit should be set.This report clarifies to what extent and under which circumstances it is possible to determine the size of microholes by measuring the electrolyte conductance.The results establish that this measuring method is capable of indicating holes as small as 0.8 μm in diameter, provided that no hole is longer than 1 mm and direct current is used for the measurement. The accuracy of the method is reduced with increasing hole length. If, for example, the length of the hole is 10 mm, as it could be in a defective seal, the method only distinguishes holes that have diameters in excess of 3 μm. The analysis also shows that the accuracy of the method in measuring the hole diameter depends upon the accuracy in determining the hole length. An underestimation of the hole length results in an underestimation of the hole diameter and vice versa.The method also detects holes that do not completely penetrate the packaging material, e.g. cracks in the inner layer of the wall material, provided that the wall material is laminated with aluminium foil. Where such defects are present, a galvani‐cally generated current occurs, the size of which reveals the size of the defect in question.The method has also been applied to a number of aseptic packagings/products bought at random. It was found that microholes and other defects were surprisingly frequent — about 40% of the packagings had detectable microholes/defects, most of them having a diameter of 10 μm, assuming the hole length to be 15 μm. Despite this, no evident infection or quality deterioration of the product could be established. The practical tolerance of microholes would therefore be even higher in the cases studied.The measuring method can be recommended for determination of microholes — their size and frequency — in packagings and it can be used as a measure of the aseptic integrity of the packagings.

The effect of chirp characteristics of directly modulated laser on the signal transmission performance is investigated by simulation. We have identified that negative dispersion shifted fiber shows performance improvement for both adiabatic and transient dominated laser. However, much better performance is observed in case of transient dominated laser. Finally equalizing fibers are inserted to compensate the further distortion induced by laser chirp and fiber nonlinearities. The simulation results suggest that by optimizing transmission fiber parameters and utilizing the repeaters after certain intervals, the performance will be further improved.

The impact of the number of pilot tones in Wimedia-defined orthogonal frequency-division multiplexed (OFDM) ultra wideband signal (UWB) transmission over fiber-to-home (FTTH) networks is experimentally analyzed. This paper analyses the expected reach and performance of multichannel OFDM-UWB transmission in adequate FTTH distances. Amplified section and standard single-mode fiber are considered. The experimental results indicate a strong dependence of the FTTH reach/performance on the number of pilot tones used to estimate the equalizer transfer function. The results reveal the number of pilot tones as an important parameter to be considered in UWB radio signals transmission over optical systems.

Metro network, as a medium distance transmission system, poses a special challenge of transmission capacity and cost. In this paper, we present a detailed comparison of applying three advanced modulation formats including pulse amplitude modulation-4 (PAM-4), carrierless amplitude and phase modulation-16 QAM (CAP-16), and discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S OFDM) with low-cost direct detection for 100-Gb/s/λ metro optical transmission systems. These modulation formats are all experimentally demonstrated with similar digital signal processing algorithms. Three kinds of chromatic dispersion (CD) compensation ways named CD precompensation method, single sideband (SSB), and dispersion compensating fiber (DCF) are also compared. Two types of modulators including an IQ modulator and a dual-drive Mach–Zehnder modulator are employed to generate SSB or CD precompensated signals in this experiment and their transmission performance is also evaluated. To the best of our knowledge, this is the first time that the performance of single-wavelength 100-G signal transmission based on direct detection is evaluated over 480 km of standard single mode fiber with PAM-4, CAP-16, and DFT-S OFDM modulation formats.

In the measurements of regional cerebral blood flow (rCBF) using inhalation of 133Xe gas, the activity present is generally limited in lower levels than those of usual brain scintigraphy. Measurements with low count-rate are usually resulted in diminishing the accuracies of results obtained. Therefore, it is necessary to make measurements using a high sensitive collimator for getting as much count-rate as possible when a gamma camera is used. The relationships among sensitivity and structures of multi-parallel collimator were mathematically analyzed. The results of analysis suggested that sensitivity usually increased by using a collimator with holes of reduced height and diameter. A prototype multi-parallel collimator with holes of low height and small diameter was made in our laboratory for testing sensitivity and resolution. The collimator possessing 1141 holes of 6 mm phi in hole diameter, 1.5 cm is hole height and septal thickness of 1 mm lead showed 24 times more sensitive than those of a general all purpose collimator supplied by the manufacturer. However, resolution measured in FWHM was of 9 to 14 mm at the collimator face and of 29 to 38 mm at 5 cm from the face. The results indicated that this collimator was useful enough in rCBF measurements with 133Xe inhalation using a gamma camera. The mathematical analysis however, suggested that optimum collimator for rCBF measurements was approximate 4.5 mm phi in hole diameter and 1.0 cm in hole height.