This letter presents an innovative power amplifier (PA) behavioral model (BM) method valid for a range of different ambient temperatures and input power levels. This work presents a novel input image ...layer for a real-valued time-delay convolutional neural network (RVTDCNN). This image layer uses preprocessed ambient temperature and dissipated power. The preprocessed temperature and power as well as the present samples are placed in a central position inside the image layer. This maximizes the number of convolution operations that they are included in thereby magnifying the importance of these inputs in the feature maps. The newly proposed method delivers, in comparable conditions, a normalized mean square error (NMSE) improvement of over 3 dB compared to a previously published method.
This paper aims to find all static states, including stable and unstable states, of electrostatically actuated microelectromechanical systems (MEMS) device models. We apply the numerical ...path-following technique to solve for the curve connecting the static states. We demonstrate that device models with 2 DOF can already exhibit symmetry-breaking bifurcations in the curve of static states and can have multiple disjoint solution paths. These features are also found in a finite-element method (FEM) model for a flexible beam suspended by a torsion spring. We have observed multiple hysteresis loops in measurements of a capacitive RF-MEMS device and have captured the qualitative features of these measurements in a model with 5 DOF. Numerical procedures for determining stability of solutions and finding bifurcation points are provided. Numerical path following is shown to be an efficient technique to find the curve of static states both in low-dimensional models and in FEM models.
We present a fast radio frequency-capacitance-voltage (RF-CV) method to measure the CV relation of an electronic device. The approach is more accurate, much faster, and more cost effective compared ...to the existing off-the-shelf solutions. Capacitances are determined using a single-frequency 1-port S-parameter setup constructed from discrete components. We introduce a new way to correct for nonlinearities of the used components, which greatly increases the accuracy with which the phase and magnitude of the reflected signal is measured. The measurement technique is validated on an RF microelectromechanical systems capacitive switch and a barium-strontium-titanate tunable capacitor. Complete CV curves are measured in less than a millisecond, with a measurement accuracy well below 1%.
Non-linearities play an important role in micro- and nano- electromechanical system (MEMS and NEMS) design. In common electrostatic and magnetic actuators, the forces and voltages can depend in a ...non-linear way on position, charge, current and magnetic flux. Mechanical spring structures can cause additional non-linearities via material, geometrical and contact effects. For the design and operation of non-linear MEMS devices it is essential to be able to model and simulate such non-linearities. However, when there are many degrees of freedom, it becomes difficult to find all equilibrium solutions of the non-linear equations and to determine their stability. In these cases path following methods can be a powerful mathematical tool. In this paper we will show how path following methods can be used to determine the equilibria and stability of electromechanical devices. Based on the energy, work and the Hamiltonian of electromechanical systems (section 1), the equations of motion (section 2), the equilibrium (section 3) and stability conditions (section 6) are derived. Examples of path following simulations (section 4) in Mathematica (section 5), Matcont (section 7) and using FEM methods in Comsol (section 8) are given to illustrate the methods.
Non-linearities play an important role in micro- and nano-electromechanical system (MEMS and NEMS) design. In common electrostatic and magnetic actuators, the forces and voltages can depend in a ...non-linear way on position, charge, current and magnetic flux. Mechanical spring structures can cause additional non-linearities via material, geometrical and contact effects. For the design and operation of non-linear MEMS devices it is essential to be able to model and simulate such non-linearities. However, when there are many degrees of freedom, it becomes difficult to find all equilibrium solutions of the non-linear equations and to determine their stability. In this paper a generic methodology to analyze MEMS devices using path following methods is described. Starting from the energy and work expressions of electromechanical systems (Section 1), the equations of motion, the equilibrium and stability conditions are derived (Sections 2, 3 and 4). The basics of path following are introduced in Section 4. Using several examples it is discussed how path following can be implemented in Mathematica, Matcont and in the FEM package Comsol (Sections 5–8).
The capacitance versus actuation voltage, the C-V curve, is characteristic for the steady state behavior of a RF-MEMS capacitive switch. It is imperative to have an efficient method to simulate these ...curves and overcome the convergence problems from pull-in and release instability that is inherent to these electrostatic actuated devices. In this paper we show how the complete CV curve can be calculated in FE code, including conditionally stable parts and zipping regions, which also comprises a non-linear contact model. Efficiency improvement by use of a reduced order model for the electrostatic domain is shown. Validity of the simulation results is shown by comparison to measurements.
For predicting dynamic responses of electrostatically actuated RF-MEMS it is imperative to be able to include fluid squeeze film effects (air damping) in a directly coupled electrostatic-mechanical ...model, in an efficient and accurate way. This paper presents the modeling methodology to predict the dynamic response of a capacitive RF-MEMS obtained with implementation of a isothermal non-linear compressible Reynolds equation in a directly coupled fluid-structural element in a pre-release of the Ansys FE software. Multi-physics simulations of harmonic (AC) responses and transient switching cycles, in which the switch closes and non-linear contact is included, were validated with measurements. It is concluded that the presented multi-physics model is a powerful tool for virtual device design and indispensable for predicting functional performance of RF-MEMS. This model provides more accurate transient results than models based on the linearized Reynolds equations.
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