Exploiting the Terahertz Band for Radionavigation

This paper demonstrates the feasibility of GPS-like ranging at terahertz (THz) frequencies. It is well established that GPS carrier signals are vulnerable to jamming via radio-frequency interference (RFI). As a result, there is a need for alternative radionavigation systems. THz signals offer a compelling option. Because of their high frequency (roughly ×100 higher than GPS), THz signals can be used to make highly precise range measurements. In addition, the large separation between the GPS and THz frequencies means that interference at GPS frequencies is very unlikely to impact the THz band. This paper lays the groundwork for a GPS-like ranging capability at THz frequencies. To this end, we identify key differences between THz hardware and GPS (radio frequency) hardware; we experimentally evaluate performance of a 0.30-THz system on a compact outdoor test range, and we introduce a measurement error model that highlights the distinctive role that multipath interference plays at THz frequencies.     

Microporous,Crystalline, and Water-Processable Framework Materials of Organic Amphiphile Salts

Porous framework materials are of major importance for a wide range of technologies. Nevertheless, many of these materials lack processibility as they are typically synthesized under rather harsh conditions and obtained as microcrystalline powders that cannot easily be coated or deposited from solution. Herein, a new approach to water-processable metal–organic framework materials is presented. The materials are based on amphiphilic organic building blocks consisting of polar carboxylate groups and non-polar alkyl chains connected to a rigid aromatic core. The amphiphilic building blocks assemble to porous framework structures via bonding to kinetically labile sodium ions from concentrated aqueous solution. The obtained crystalline materials, termed amphiphile salt frameworks , are thermally and mechanically stable (some derivatives up to 365 °C and up to at least 4000 bar hydrostatic pressure), exhibit persistent microporous channels accessible to several gases (N₂, CO₂, propane, propylene, n-butane), and can be reversibly assembled/disassembled by crystallization from or dissolution in water. Systematic variation of the hydrophobic side chains of the amphiphile building blocks allows extracting structure-property relationships and first design rules for this new class of water-processable microporous framework materials.     

Self-organizing technique for improving coverage in connected mobile objects networks

Despite the multiple benefits offered today by connected mobile objects networks (CMONs), some constraints continue to limit their development and to degrade their applications and services’ performance. Given their limited energy, some or many objects may stop functioning which leads to the deterioration of network functionalities such as monitoring, detection and transfer of data. It is in this context that our work is situated, namely the improvement of applications performance and the quality of service (QoS) within CMONs, by exploiting some communication environment parameters and geometry techniques. We propose a new technique called self-organization area coverage (SOAC) for CMONs which aims to ensure maximum coverage in the network while optimizing the exploited resources. SOAC has been evaluated and compared not only to the network without improvement but to two other solutions proposed in the literature. The obtained results show a clear improvement in terms of network coverage and several QoS parameters.     

High pass filter with above IC integrated SrTiO3 high K MIM capacitors

This paper describes realization and characterization of SrTiO₃ (STO) high K MIM capacitors above BiCMOS integrated circuit (IC). These capacitances are connected to IC and are used as coupling capacitors in order to realize a high pass filter. Surface capacitance achieved is 10 nF/mm² with capacitance value of 1.2 nF. The process for STO MIM fabrication does not exceed 400 °C, which is compatible with interconnections. Typical K and dielectric losses values obtained are, respectively 110% and 2%. Yield obtained reaches 83% for capacitors. A functional high pass filter using these STO capacitors was realized in this study. It exhibits a cut-off frequency at 6.5 kHz and a constant gain at higher frequencies of −1.3 dB.     

Localized Ligand Induced Electroless Plating (LIEP) Process for the Fabrication of Copper Patterns Onto Flexible Polymer Substrates

The “ligand induced electroless plating (LIEP) process” is a simple process to obtain localized metal plating onto flexible polymers such as poly(ethylene terephtalate) and polyvinylidene fluoride sheets. This generic and cost‐effective process, efficient on any common polymer surface, is based on the covalent grafting by the GraftFast process of a thin chelating polymer film, such as poly(acrylic acid), which can complex copper ions. The entrapped copper ions are then chemically reduced in situ and the resulting Cu⁰ species act as a seed layer for the electroless copper growth which, thus, starts inside the host polymer. The present work focuses on the application of the LIEP process to the patterning of localized metallic tracks via two simple lithographic methods. The first is based on a standard photolithography process using a positive photoresist masking to prevent the covalent grafting of PAA in designated areas of the polymer substrate. In the second, the patterning is performed by direct printing of the mask with a commercial laser printer. In both cases, the mask was lifted off before the copper electroless plating step, which provides ecological benefits, since only the amount of copper necessary for the metallic patterning is used.     

车载视觉武装司机

使车载视觉变成现实的大部分必要技术已经问世。未来,我们将看到具有视觉功能、为司机提建议、甚至自动对道路、交通状况以及天气变化做出响应的汽车。其中两种关键技术,即能够把原始图像转换成可用信息的数码     

Comparison of low frequency noise and high frequency performances of double and simple polysilicon Bi-CMOS BJT

The issue of this paper concerns 0.35 μm Bi-CMOS double polysilicon bipolar transistors and 0.5 μm Bi-CMOS simple polysilicon bipolar transistors. Low-frequency noise measurements are performed. Noise spectral densities are analysed versus bias and geometry. From these noise measurements, base and emitter series resistances are extracted. A comparison of both technologies is done. Though double polysilicon transistors have a more complex structure than the simple polysilicon ones, they exhibit similar or even better performances. Indeed, DC characteristics and noise levels are equivalent for both technologies. Double polysilicon transistors exhibit a reduction of the base resistance and a significant improvement of the transition frequency f_T is obtained.     

A Behavioral Model of MEMS Convective Accelerometers for the Evaluation of Design and Calibration Strategies at System Level

This paper presents a behavioral model that can be used to improve the manufacturability of systems based on MEMS convective sensors. This model permits to handle faults related to process scattering, taking into account not only the electrical and lateral geometrical parameters but also the influence of the cavity depth. Moreover correlations between conductive and convective phenomena are included. The model is validated with respect to FEM simulations and a very good agreement is obtained between the behavioral model and FEM results. The proposed model can then be used in system-level simulations, for instance to evaluate the impact of process scattering on the performances of the sensing part and/or to investigate different design and calibration strategies with respect to the system robustness.     

Joint Estimation of Location and Scatter in Complex Elliptically Symmetric Distributions

The joint estimation of the location vector and the shape matrix of a set of independent and identically Complex Elliptically Symmetric (CES) distributed observations is investigated from both the theoretical and computational viewpoints. This joint estimation problem is framed in the original context of semiparametric models allowing us to handle the (generally unknown) density generator as an infinite-dimensional nuisance parameter. In the first part of the paper, a computationally efficient and memory saving implementation of the robust and semiparmaetric efficient R-estimator for shape matrices is derived. Building upon this result, in the second part, a joint estimator, relying on the Tyler’s M-estimator of location and on the R-estimator of shape matrix, is proposed and its Mean Squared Error (MSE) performance compared with the Semiparametric Cramér-Rao Bound (SCRB).

     

Improvement of conical corrugated horn analysis using Gaussianbeams

The classical analysis of a conical corrugated horn is extended out of the balanced hybrid conditions using a vectorial multimodal Gaussian beam expansion. An experimental validation is also presented