Extraction of small-signal model parameters of Si/SiGe heterojunction bipolar transistor using least squares support vector machines

A novel straightforward methodology for extracting bias-dependent small-signal equivalent circuit model parameters (SSECMPs) of silicon/silicon–germanium heterojunction bipolar transistors is presented. The inverse mapping between SSECMPs and scattering (S) parameters is established and fitted using simulated data of the SSECM. Since the problem has large input space, S-parameters at many frequency points, the least squares support vector machines concept is used as regression technique. Physical SSECMPs values are obtained using the proposed methodology. Moreover, an excellent agreement is noted between the S-parameters measurements and their simulated counterpart using the extracted SSECMPs in the frequency range from 40 MHz to 40 GHz at different bias conditions

Efficient procedure for capacitance matrix calculation of multilayer VLSI interconnects using quasi-static analysis and Fourier series approach, Journal of Telecommunications and Information Technology, 2002, nr 2

In this paper, we present a new approach for capacitance matrix calculation of lossy multilayer VLSI interconnects based on quasi-static analysis and Fourier projection technique. The formulation is independent from the position of the interconnect conductors and number of layers in the structure, and is especially adequate to model 2D and 3D layered structures with planar boundaries. Thanks to the quasi-static algorithms considered for the capacitance analysis and the expansions in terms of convergent Fourier series the tool is reliable and very efficient; results can be obtained with relatively little programming effort. The validity of the technique is verified by comparing its results with on-surface MEI method, moment method for total charges in the structure, and CAD-oriented equivalent-circuit methodology, respectively

Cross-Memory Polynomial Modeling for RF Circuits

A new behavioral model is proposed which can provide similar accuracy to the memory polynomial model (MPM) but is shown to have a more efficient architecture for digital hardware implementation. These features have been achieved by the proposed formulation, in which the nonlinear weights of the memory terms are a function of only the present input sample. The new approach is evaluated and compared with the conventional MPM using a Wideband Code Division Multiple Access (WCDMA) signal applied to two different amplifier circuits

Comparison of Field-To-Line Coupling Models: Coupled Transmission Lines Model versus Single-cell Corrected Taylor Model

International audienceModels for field-to-line coupling are interesting be- cause they help to predict the immunity of PCBs and explain the relation between routing and immunity. In this article a meandered PCB trace illuminated by EM field in a TEM cell is analysed. The near-end and far-end coupling is predicted using two models: a detailed and an approximative one. The detailed model is a circuit of coupled multi-conductor transmission lines evaluated with a circuit simulator. The approximative model consists of a single Taylor cell with an analytical modification evaluated using a numerical computing tool. Both predictions are compared with measurements and turn out to be equally precise. The advantage of the coupled lines model is its flexibility, the advantage of the modified Taylor model is its ease of use

A Synthetic HIV-1 Subtype C Backbone Generates Comparable PR and RT Resistance Profiles to a Subtype B Backbone in a Recombinant Virus Assay

In order to determine phenotypic protease and reverse transcriptase inhibitor-associated resistance in HIV subtype C virus, we have synthetically constructed an HIV-1 subtype C (HIV-1-C) viral backbone for use in a recombinant virus assay. The in silico designed viral genome was divided into 4 fragments, which were chemically synthesized and joined together by conventional subcloning. Subsequently, gag-protease-reverse-transcriptase (GPRT) fragments from 8 HIV-1 subtype C-infected patient samples were RT-PCR-amplified and cloned into the HIV-1-C backbone (deleted for GPRT) using In-Fusion reagents. Recombinant viruses (1 to 5 per patient sample) were produced in MT4-eGFP cells where cyto-pathogenic effect (CPE), p24 and Viral Load (VL) were monitored. The resulting HIV-1-C recombinant virus stocks (RVS) were added to MT4-eGFP cells in the presence of serial dilutions of antiretroviral drugs (PI, NNRTI, NRTI) to determine the fold-change in IC50 compared to the IC50 of wild-type HIV-1 virus. Additionally, viral RNA was extracted from the HIV-1-C RVS and the amplified GPRT products were used to generate recombinant virus in a subtype B backbone. Phenotypic resistance profiles in a subtype B and subtype C backbone were compared. The following observations were made: i) functional, infectious HIV-1 subtype C viruses were generated, confirmed by VL and p24 measurements; ii) their rate of infection was slower than viruses generated in the subtype B backbone; iii) they did not produce clear CPE in MT4 cells; and iv) drug resistance profiles generated in both backbones were very similar, including re-sensitizing effects like M184V on AZT

Controlled Measurement Setup for Ultra-Wideband Dielectric Modeling of Muscle Tissue in 20–45 °C Temperature Range

In order to design electromagnetic applicators for diagnostic and therapeutic applications, an adequate dielectric tissue model is required. In addition, tissue temperature will heavily influence the dielectric properties and the dielectric model should, thus, be extended to incorporate this temperature dependence. Thus, this work has a dual purpose. Given the influence of temperature, dehydration, and probe-to-tissue contact pressure on dielectric measurements, this work will initially present the first setup to actively control and monitor the temperature of the sample, the dehydration rate of the investigated sample, and the applied probe-to-tissue contact pressure. Secondly, this work measured the dielectric properties of porcine muscle in the 0.5–40 GHz frequency range for temperatures from 20 °C to 45 °C. Following measurements, a single-pole Cole–Cole model is presented, in which the five Cole–Cole parameters (ϵ∞, σs, Δϵ, τ, and α) are given by a first order polynomial as function of tissue temperature. The dielectric model closely agrees with the limited dielectric models known in literature for muscle tissue at 37 °C, which makes it suited for the design of in vivo applicators. Furthermore, the dielectric data at 41–45 °C is of great importance for the design of hyperthermia applicators

Controlled Measurement Setup for Ultra-Wideband Dielectric Modeling of Muscle Tissue in 20–45 °C Temperature Range

In order to design electromagnetic applicators for diagnostic and therapeutic applications, an adequate dielectric tissue model is required. In addition, tissue temperature will heavily influence the dielectric properties and the dielectric model should, thus, be extended to incorporate this temperature dependence. Thus, this work has a dual purpose. Given the influence of temperature, dehydration, and probe-to-tissue contact pressure on dielectric measurements, this work will initially present the first setup to actively control and monitor the temperature of the sample, the dehydration rate of the investigated sample, and the applied probe-to-tissue contact pressure. Secondly, this work measured the dielectric properties of porcine muscle in the 0.5–40 GHz frequency range for temperatures from 20 °C to 45 °C. Following measurements, a single-pole Cole–Cole model is presented, in which the five Cole–Cole parameters (ϵ∞, σs, Δϵ, τ, and α) are given by a first order polynomial as function of tissue temperature. The dielectric model closely agrees with the limited dielectric models known in literature for muscle tissue at 37 °C, which makes it suited for the design of in vivo applicators. Furthermore, the dielectric data at 41–45 °C is of great importance for the design of hyperthermia applicators

Een analysemodel voor roosters van rechthoekige microstripantennes

SIGLEKULeuven Campusbibliotheek Exacte Wetenschappen / UCL - Université Catholique de LouvainBEBelgiu