Aerodynamic behavior of the bridge of a capacitive RF MEMS switch

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The present paper proposes a coupled 3D multi-physics model and presents the results of its transient simulation, for a RF MEMS capacitive switch of bridge-type. The fluid structure interaction (FSI) simulation sustains time-varying viscous damping and modified time response of the bridge deflection compared to the actuation modulation above closing of the switch. Complex 3D geometries of the bridge were rarely taken into account in viscous damping assessment much less in the simulation of the full flow around the bridge of the switch. The final goal of the paper is to obtain the dependency of an equivalent damping coefficient with respect to time, to be used in subsequent reduced order models for the switch, that include the aerodynamic behaviour of the switch

Parasitic inductive coupling of integrated circuits with their environment

This paper describes an original methodology for the modeling of parasitic inductive couplings. The key idea is the use of magnetic hooks which are gates for magnetic fluxes that cross conductive loops and consequently induce parasitic voltages, thus disturbing the signal integrity. The multiple connected domains of integrated circuits are modeled by a Magneto-Electric-Equivalent-Circuit (MEEC), consisting of two mutual coupled circuits, an electric and magnetic one. Magnetic hooks are the externally connected nodes of the magnetic circuit. © 2014 The Institute of Electronics, Information and Communication Engineer. Keywords: Chip; Computational Electromagnetics; IC & Semiconductor EMC; Numerical Modeling; Signal Integrit

Parametric models based on the adjoint field technique for RF passive integrated components

Taking into consideration the variability specific to the nowadays nanotechnologies, the fast extraction of parametric models is a must for the present VLSI and radio-frequency (RF)-integrated-circuit (IC) design environments. The major contribution of the paper is a new, effective methodology for the extraction of parametric compact models for passive RF integrated components with field effects, valid for high-frequency broad range. The proposed numeric method is systematically based on a dual approach, which provides two complementary approximations of the exact solution. Duality is applied both to the spaces where the discrete solution is found as well as to the open boundary conditions. The adjoint field technique is applied in an original manner to the finite-integral techniques to handle the parameter variability of the extracted model. The new method needs much less computing resources for modeling than other numerical methods

MOESP algorithm for converting one-dimensional Maxwell equation into a linear system

We present a method for converting 1-D Maxwell equation into a linear system using the Multivariable Output Error State Space (MOESP) method, a subspace system identification method. To show the efficiency of the method, we first apply it to a set of ordinary differantial equations. Input and output from the equation set are computed by numerical methods and the obtained data is used for building the required matrices. An appropriate Single Input Single Output (SISO) linear system is estimated by MOESP algorithm for the equation at hand. The goal of the research is to build a low order linear state space system model for the Maxwell equation. On the other hand the order estimation for the system can be used in other way. For example, with this estimation one can determine an appropriate order for the physical system, for which one of the well-known model order reduction techniques can be used to obtain a reduced order model

Incorporating the Avoidance Behavior to the Standard Particle Swarm Optimization 2011

Inspired from social and cognitive behaviors of animals living as swarms; particle swarm optimization (PSO) provides a simple but very powerful tool for researchers who are dealing with collective intelligence. The algorithm depends on modeling the very basic random behavior (i.e. exploration capability) of individuals in addition to their tendency to revisit positions of good memories (cognitive behavior) and tendency to keep an eye on and follow the majority of swarm members (social behavior). The balance among these three major behaviors is the key of success of the algorithm. On the other hand, there are other social and cognitive phenomena, which might be useful for improvement of the algorithm. In this paper, we particularly investigate avoidance from the bad behavior. We propose modifications about modeling the Standard PSO 2011 formulation, and we test performance of our proposals at each step via benchmark functions, and compare the results of the proposed algorithms with well-known algorithms. Our results show that incorporation of Social Avoidance behavior into SPSO11 improves the performance. It is also shown that in case the Social Avoidance behavior is applied in an adaptive manner at the very first iterations of the algorithm, there might be further improvements

Models for integrated components coupled with their EM environment

Abstract: Purpose – The main aim of this study is the modelling of the interaction of on-chip components with their electromagnetic environment. Design/methodology/approach – The integrated circuit is decomposed in passive and active components interconnected by means of terminals and connectors which represent intentional and parasitic couplings of a capacitive and inductive nature. Reduced order models are extracted independently for each component. Findings – The paper shows that one of the main theoretical problems encountered in the modelling of RF components is the difficulty to define a unique terminal voltage, independent of the integration path (this independence being a condition to allow the connection of the component in an electric circuit, where the voltage does not depend of the path shape). The concept of an electromagnetic circuit element that allows the interconnection between IC models is proposed as a solution for this drawback. The system is described either with EM field models, or by electric/magnetic circuits. By using the new concept of hooks, the EM interaction is described effectively with a reduced number of quantities. Research limitations/implications – Since hooks have a virtual character, their identification is the result of an optimization procedure. By increasing their number the model accuracy is improved as also is the computational effort. The optimal automatic identification of electric and magnetic hooks is the subject of further research. Currently, the hooks are placed manually. Practical implications – The modelling of IC components with hooks is part of a new methodology that takes a layout description of typical RF functional blocks that will operate at RF frequencies up to 60?GHz and transform them into sufficiently accurate, reliable electrical simulation models, taking EM coupling and variability into account. This will decrease extra design iterations, over-dimensioning or complete failures in the design cycle of RF-IC. Originality/value – For the first time, the concept of magnetic terminals is used to describe interactions in RF integrated circuits. These EM "hooks" are defined in mathematical terms, as proper boundary conditions. The concept of hooks is also new. The proposed modeling methodology for EM coupling is also new. The paper is useful for nEDA designers