Design and Optimization of RF ICs with Embedded Linear Macromodels of Multiport MEMS Devices Yong Jae Lee, 1 Yong-Hwa Park, 2 Feng Niu, 3 Dejan Filipovic 1 1 ECOT 243, Department of Electrical and Computer Engineering, University of Colorado, Boulder, CO 80309-0425 2 Visual Display Division, Samsung Electronics Company, Ltd., Suwon, Korea 3 Florida Communication Research Labs, Motorola, Inc., Plantation, FL 33322 Received 9 December 2005; accepted 31 March 2006 ABSTRACT: In this paper, we demonstrate efficient modeling approach for simulation, analysis, design, and optimization of multiport radio frequency microelectromechanical sys- tems (RF MEMS) resonating structures embedded in RF circuits. An in-house finite element method (FEM) solver is utilized to develop accurate and efficient macromodels that capture all the essential characteristics of the device. Using the datasets generated from the FEM simulations, the artificial neural network models are trained for two-way mapping between the physical input and electrical output parameters. Realized model is implemented in a cir- cuit simulator, enabling a simple yet accurate circuit simulator compatible modeling and optimization procedure instead of memory and time demanding FEM analysis. The deriva- tion of dynamic macromodels with preserved electromechanical behavior of the multiport resonating structures is also presented. Capabilities of the proposed approach are demon- strated with several examples featuring capacitively actuated MEMS resonating structures: a clamped–clamped beam, a free–free beam, and a coupled clamped–clamped beam. V V C 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE 17: 196–209, 2007. Keywords: ART neural network; computer-aided design; finite element methods; microelectro- mechanical devices I. INTRODUCTION Microelectromechanical system (MEMS) devices offer high quality performance while maintaining the small size, low power consumption, low cost, and other desirable features for modern communication systems. To further reduce the cost of MEMS fabri- cation, the reliable computer-aided engineering becomes increasingly important. At present time, the software-based design of RF circuits with embedded MEMS devices is inadequate because it requires sep- arate software packages for mechanical and RF domains. However, modeling of MEMS devices in individual physics-based domains is mature as veri- fied by many publications. For example, electromag- netic [1, 2] and electromechanical [3, 4] commer- cially available software tools have been traditionally utilized and typically excellent results are reported. A hybrid finite element-boundary integral-method of moment (FE-BI-MOM) [5] is employed for modeling capacitive RF MEMS switches in the frequency do- main, while an efficient finite difference time domain scheme is utilized for RF MEMS tuners [6]. If a physical structure of a device is known but exact Correspondence to: D. Filipovic; e-mail: dejan@colorado.edu DOI 10.1002/mmce.20214 Published online 1 March 2007 in Wiley InterScience (www. interscience.wiley.com). V V C 2007 Wiley Periodicals, Inc. 196