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Item type:Publication, Access status: without files , Functional via structures in passive microwave components on multilayer ceramic substratesPublicationtype: Doctoral Thesis53 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Analysis of Differential Crosstalk and Transmission for Via Arrays in Low Temperature Cofired Ceramics(2021-05); ; ; ; Given the ubiquitous use of via arrays in multilayer substrates based on organic materials, this work explores ceramic-based solutions instead. Assuming typical design and technology constraints, the performance of via arrays on low temperature cofired ceramics is studied in terms of crosstalk as well as transmission. Both single-ended and differential signaling are considered, thus covering a broad range of use cases for microwave applications and high-speed digital links. By employing single vias optimized with respect to 50O systems as fundamental building blocks for larger via arrays, different array configurations are proposed and analyzed. The question as to what moving from organic to ceramic materials and vice versa implies in terms of electrical performance is investigated. The majority of the work is based on the computationally efficient physics-based via modeling technique due to the size and complexity of the via array models, but comparisons to conventional full-wave solvers show strong agreement between the two methods up to 50GHz.Publicationtype: Conference Paper32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Vertical Integration of Passive Microwave Components Using Functional Via Structures in LTCC Multilayer SubstratesA recently developed concept for designing passive microwave components using functional vertical interconnect accesses (vias) for vertical integration in printed circuit boards (PCBs) is extended and transferred to the low temperature cofired ceramic (LTCC) technology. Given the changed material properties and new technology constraints, it is shown how and to what extent the controlled vertical interconnect accesses (via) structures can behave as quasi-transmission lines, thus allowing for another degree of freedom in component design. To demonstrate the validity and utility of functional vias, several novel microwave components are proposed and subsequently analyzed including vertically integrated 2- and 3-way Wilkinson power dividers, as well as vertically integrated 90° and 180° hybrid couplers. Prototypes for the 2-way and 3-way power dividers were manufactured on an LTCC multilayer substrate. Both measurement and full-wave simulation results are in excellent agreement and thus provide a proof of the concept.Publicationtype: Journal Article59 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Introducing Functional Via Structures to Low Temperature Cofired Ceramics: How to Optimize Reliably and Efficiently(2021-02-11); ; ; ; Low temperature cofired ceramics (LTCCs) refer to a mature technology with low-loss dielectric materials, high quality conductors, and high dimensional accuracy. This class of ceramics-based substrates is a popular choice for integration of a variety of electronics with active and passive components in both single- and multilayered environments. Vertical interconnect accesses (vias) are widely used in LTCC and elsewhere for signal routing as well as power and ground supply within the stack-up. Since vias represent discontinuities in the signal path, they introduce parasitic elements that inevitably degrade the electrical performance. This work intends to delineate two distinct, straightforward, and efficient ways to estimate as well as control via impedance and phase delay. The usability of vias in LTCC is extended through the concept of functional via structures, which is based on the generalization of vias as quasi-coaxial lines that behave similarly to real transmission lines. The advantage of the proposed concept is highlighted by deploying vias for three-dimensional (3-D) integration of power dividers, and improving the signal integrity (SI) and power integrity (PI) of via arrays in LTCC multilayered substrates.Publicationtype: Journal Article21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Vertically Integrated Microwave-Filters Using Functional Via Structures in LTCCA novel approach to filter design including proof of concept is demonstrated through the first-time vertical integration of Chebyshev lowpass- and bandpass-filters in low temperature cofired ceramic (LTCC) multilayered substrates. Integration is achieved by replacing planar stub elements by resonant vertical interconnect accesses (vias) which serve the functional purpose of a vertical transmission line and therefor add another full degree of freedom in circuit design. The filters shown are comprised of two lowpass filters of 3rd- and 5th-order, and one bandpass filter of 5th-order. The general description of the design is given together with full filter specifications. Full-wave simulations based on the finite element method (FEM) and measurement results are compared to each other and are in excellent agreement.Publicationtype: Conference Paper37 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Design of Wideband Functional Via Structures for LTCC Multilayer Substrates up to 110 GHzPublicationtype: Conference Paper95 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Design of experiments for analyzing the efficiency of a multi-coil wireless power transfer system using polynomial chaos expansionPitch distances of single coils in multi-coil wireless power transfer systems have a substantial impact on the efficiency. But traditional full factorial (FF) design of experiments is time-consuming due to the large number of measurements in order to describe the efficiency with varying pitch distances. In this paper, polynomial chaos expansion (PCE) is applied to construct a design of experiments and to obtain a surrogate model of the efficiency of a multi-coil system. Instead of large-scale FF, the proposed method reduces the maximum number of necessary measurements by a factor of 6 to 20, while providing accurate information on the efficiency. The agreement between the results of the PCE function and FF design is analyzed in order to validate the method.Publicationtype: Conference Paper101 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Quantifying the impact of RF probing variability on TRL calibration for LTCC substrates(2019-05); ; When conducting radio frequency (RF) measurements using microwave probes, slight misplacements of the probing tips introduce errors and deteriorate measurement results, especially in the case of manual probing. For this reason, short transmission lines in combination with polynomial chaos expansion (PCE) are used to model the imperfect conncections between probes and launching structures, and to quantify the impact of probing inaccuracies on the thru-reflect-line (TRL) calibration technique. The analysis is accompanied by a comparison between PCE and Monte Carlo sampling (MCS) in order to assess the accuracy of the proposed method. Additionally, a set of microstrip TRL standards are manufactured on a low temperature cofired ceramic (LTCC) substrate and subsequently measured in the frequency range from 0.05 to 50 GHz for the purpose of studying the correlation with the underlying PCE model.Publicationtype: Conference Paper171 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Variance-Based Iterative Model Order Reduction of Equivalent Circuits for EMC AnalysisThis paper proposes a novel and iterative way to conduct model order reduction (MOR) of linear equivalent circuit models (ECMs) without the use of a state-space representation as a surrogate model. The result is an ECM with a reduced total number of circuit elements but same system behavior. The proposed method is as follows: first, the original ECM is decomposed into smaller subcircuits after which a variance-based global sensitivity analysis by means of polynomial chaos expansion is conducted in order to extract the Sobol indices which measure the relative impact of the circuit elements. The least influential ones are then removed by either shorting them or replacing them by an electric open. The frequency responses of the resulting reduced circuits are then fitted against the original frequency response through nonlinear least squares optimization and by subsequently updating the element values. As opposed to the traditional MOR techniques from systems theory, the proposed approach operates on the ECM themselves directly. Thus, it not only offers additional physical insight into the system at any iteration step but also inherently leads to reduced-order models that are at once stable, causal, and passive. This makes the approach especially useful for practical electromagnetic compatibility problems and analysis. In the following, this novel approach is first described in detail and then applied to different test cases. Finally, a discussion of its limitations will be given.Publicationtype: Journal Article160 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Feasibility of uncertainty quantification for power distribution network modeling using PCE and a contour integral method(2018-06-22); ; ; ; This work presents the modeling of the printed circuit board part of power distribution networks (PDNs) and example results for the uncertainty quantification for the magnitude of the corresponding impedance. Variability is considered for several parameters, including geometry, material properties, and the models of the decoupling capacitors. For the computation of the parallel plate impedance an efficient and accurate two-dimensional contour integral method (CIM) is applied together with models for the wave number for the complete frequency range of interest. Polynomial chaos expansion (PCE) is used in the non-intrusive form of stochastic testing for the uncertainty quantification and Monte Carlo simulations are used for the validation of these results. To our knowledge this combination of methods represents the first application of CIM and PCE to the modeling of PDNs. The PCE is found to be numerically more efficient than Monte Carlo in cases where parameters are varied that have an influence on the parallel plate impedance. It can be less efficient for variation of only the models of decoupling capacitors. It is applicable if not too many parameters are varied at a time and accurate if resonance effects due to low-loss substrate materials and components are not too pronounced at the considered frequency.Publicationtype: Conference Paper214