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Item type:Publication, Access status: without files , Sensitivity analysis and empirical optimization of cross-domain coupling on RFICs using polynomial chaos expansionThis work aims at investigating the variability of internal coupling mechanisms between different domains of a Radio Frequency Integrated Circuit (RFIC). In doing so, an Equivalent Circuit Model (ECM) is used in order to model the various coupling paths. First, the elements of the ECM are assumed to be uniformly distributed and their exact values therefore not fully known. Afterwards, the impact of theses uncertainties on the cross-domain transfer function, i.e. the coupling from the digital domain - the aggressor - into the other more sensitive domains - the victims - is analyzed using Polynomial Chaos Expansion (PCE) in combination with a sampling-based technique known as Stochastic Testing (ST). This approach intends to account for not accurately known configurations of the RFIC and package. In addition, the PCE representation allows for conducting sensitivity analysis through the derivation of conditional variances, i.e. Sobol indices, and sensitivities. PCE in combination with ST offers an efficient way to analyze the coupling effects. Finally, an improved version of the original design is proposed using an empirical optimization approach based on the techniques described above.Publicationtype: Conference Paper109 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Efficient prediction of equalization effort and channel performance for PCB-based data links(IEEE, 2017-09-28); ; ; ; High-speed data links that utilize multilayer printed circuit boards suffer from loss, dispersion, and intersymbol interference. Often, equalization and error correction are required to make these channels functional at gigabit data rates and demand costly analyses. The characterization of loss-dominated links can be generalized and simplified by means of a normalized link length as presented herein. Based on a correlation of this normalized length and observed eye opening, a novel assessment of wired digital links for frequencies up to 50GHz and data rates up to 30 Gb/s is proposed. It allows for an efficient prediction of the amount and type of required equalization for a given link as well as determining maximum tolerable loss for a given equalizer configuration. The proposed method and its applicability are demonstrated by means of practical examples.Publicationtype: Journal Article214 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Extension of the contour integral method for stochastic modeling of waveguiding structuresElectromagnetic fields confined in a printed circuit board (PCB) cavity, the field inside a substrate integrated waveguide (SIW), and the normal scattered fields of infinitely extended structures have in common that the wave vector lies in a plane. In this thesis, the Contour Integral Method (CIM) is extended to model practical problems and devices as PCBs and planar microwave devices with inhomogeneous substrates and optical devices in TE and TM polarization. Physics-based approaches are used to incorporate transitions to the planar problem. For the handling of stochastic formulations of physics-based models, Polynomial Chaos Expansion (PCE) was used. Algorithms and methodologies are proposed to apply PCE efficiently and comprehensively. The proposed extensions and methods are validated using state of the art real world application examples.Publicationtype: Doctoral Thesis663 1219 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Variability analysis of via crosstalk using polynomial chaos expansion(IEEE, 2017-07-03); ; ; ; In this work we use the method of polynomial chaos expansion (PCE) for statistical analysis of a via interconnect in a printed circuit board (PCB) in presence of geometrical uncertainties. A physics-based via (PBV) model is applied to the case of two signal vias surrounded by ground vias. This model consist of a near-field part and a far-field part. Here, the focus is on the far-field part modeled by the contour integral method (CIM). In order to account for variability in the geometry, namely a variation of the pitch, PCE is applied to the CIM in an intrusive manner. The system matrix of the deterministic case is replaced by an augmented version. The method is validated with Monte Carlo Sampling (MC) and shows excellent agreement for a simple geometry. We observe the same agreement in more complicated geometric configurations- A t least for frequencies below the first resonance.Publicationtype: Conference Paper137 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Efficient design of continuous time linear equalization for loss dominated digital linksSignal degradation in high-speed data links can be mitigated by means of channel equalization. One preferred choice in conjunction with other techniques is the Continuous Time Linear Equalizer (CTLE) due to its effectiveness. Although CTLE being common technology, adaptation of design parameters regularly relies on trial and error. This work proposes a simple, yet very effective method for CTLE design, referred to as matched CTLE (mCTLE). It advocates channel characterization in the frequency domain which is crucial for the placement of CTLE poles and zeros. Demonstration and discussion based on typical interconnect topologies illustrate the novel approach in the context of existing literature.Publicationtype: Conference Paper86 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Efficient total crosstalk analysis of large via arrays in silicon interposers(2016-12-01); ; ; ; In this paper, we present for the first time a rigorous crosstalk analysis of through silicon via (TSV) arrays consisting of several hundreds of TSVs in interposers with metallized surfaces, using the physics-based via (PBV) modeling approach for applications up to 500 GHz. The PBV modeling approach is valid for complete and almost complete metallizations of the substrate where radial wave propagation in the parallel-plate structure dominates the electromagnetic properties and is utilized with models of good accuracy for localized and propagating fields in the inhomogeneous dielectrics. The approach shows very good to good agreement of crosstalk results for frequencies up to 500 GHz in comparison to full-wave simulations and attains a speedup of at least two orders of magnitude in comparison to general-purpose simulators. The definition of a weighted power sum for total uncorrelated crosstalk is applied for all channels in the TSV array. These power sum results give more meaningful insights into the global effects of the parameter variations than single crosstalk contributions. Based on variations of several technology and design parameters of TSVs, we derive quantitative estimations of the impact of these parameters on the total crosstalk.Publicationtype: Journal Article78 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Extension of the contour integral method for the modeling of TE scattering in two-dimensional photonic structures using the duality principleThe Contour Integral Method (CIM) is a numerically efficient modeling technique for planar or infinitely extended two-dimensional (2-D) structures. In the optical regime, the CIM has already been adapted and applied for the modeling of TM0z-mode scattering in photonic crystals. In this work the dual case of TE0z-mode scattering is addressed. Making use of the duality principle, expressions for the behavior of the TE0z-mode can be derived from the system matrices associated with the TE0z-mode. This allows to reuse use formulas and program code written for the TE0z-mode with minimal adjustments. The results are validated by comparison to full-wave simulations.Publicationtype: Conference Paper158 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Design space exploration for printed circuit board vias using polynomial chaos expansionThis work discusses how the Williamson equivalent circuit for the modeling of via transitions is augmented using the polynomial chaos expansion (PCE) method to take into account stochastic variations of model parameters. In addition, it is shown how the PCE can be applied in combination with Monte-Carlo (MC) sampling to conduct an efficient design space analysis. The physics-based via (PBV) model is used to efficiently model multilayer via interconnects by concatenating equivalent circuit models representing certain geometric sections of the interconnect. These equivalent circuits are expanded with respect to the stochastic model parameters by means of PCE and concatenated to derive an augmented model of the whole interconnect. From this representation, stochastic scattering parameters are extracted. Numerical examples verify the method and the computational advantages over MC sampling. The method provides a fast and comprehensive approach to design space exploration and variability assessment in the design stage of via interconnects. The presented approach is not limited to via models and can be applied to various microwave structures in a similar way.Publicationtype: Conference Paper92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Impact of continuous time linear equalizer variability on eye opening of high-speed linksIn this paper a variability analysis on three generic continuous-time linear equalizer (CTLE) implementations is conducted based on their respective equivalent circuits. It is studied how the simultaneous variation of all circuit elements affects a CTLE's performance. The variability analysis is conducted applying polynomial chaos expansion (PCE) with stochastic testing (ST). To obtain meaningful results, the impact of the variations on the transmission through a realistic channel, the vertical and horizontal eye opening are investigated. The eye opening and its uncertainty due to the variations of the CTLE's parameter values is analyzed for data rates from 2 to 18 Gbit/s, to compare the performance of the different CTLE implementations. Finally, the relative impact of specific circuit elements is linked to the uncertainty of the eye opening.Publicationtype: Conference Paper54 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Efficient stochastic transmission line modeling using polynomial chaos expansion with multiple variablesThe polynomial chaos expansion (PCE) is widely used in computational electromagnetics to model stochastic parameters and uncertainty. The major drawback of PCE is that the computational costs grow exponentially with the number of stochastic variables. This work presents a systematic and numerically efficient approach for the application of PCE to cascaded transmission lines where the characteristic impedances are stochastically given and independent from each other. As an example, a stepped impedance filter is analyzed containing up to 31 transmission line segments. The modeling approach is validated with Monte-Carlo (MC) and shows a very good agreement and a significant speedup. The presented method is valid for concatenation of any passive linear circuit.Publicationtype: Conference Paper71