Analytic Modeling Of RF MEMS Shunt Connected Capacitive Switches (original) (raw)
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The electromagnetic and the electromechanical characteristics of the radio frequency micro-electro-mechanicalsystem (RF MEMS) switches for high-frequency applications are the critical performance metrics that need to optimize. Performance indices of the RF MEMS switches such as isolation, insertion loss, pull-in voltage, holddown voltage, reliability are dependent on types and properties of conducting and insulating materials that are used in the construction of switch. This article proposes the design and analysis of the two terminal capacitive shunt switches built on a coplanar waveguide (CPW) for applications in subsets of Ka-and V-Band frequency range. The proposed switch used a fixed-fixed gold membrane with the low-spring constant uniform single meander flexures support and achieved a low pull-in voltage of 5.1 Volts. An impact of the variation of the geometric parameter trade-offs like conducting membrane height, dielectric material height, and the air gap between the membrane and the dielectric materials like Silicon Nitride (Si3N4) and Hafnium Dioxide (HfO2) are studied to investigate RF and electromechanical performance of the switch.
DESIGN AND ANALYSIS OF MEMS CAPACITIVE SHUNT TYPE SWITCH FOR RF APPLICATIONS
RF-MEMS is a promising technology that has the potential to revolutionize RF and microwave system implementation for next generation telecommunication applications [1]. In this paper, a MEMS capacitive shunt type switch is design and analyzed for RF applications. This new switch design focuses on the failure mechanisms restriction, the simplicity in fabrication, the power handling and consumption, as well as controllability with electromagnetic characteristics. The MEMS switch is designed in both ON and OFF states. The proposed MEMS switch has dimension of 508 µm × 620 µm with a height of 500 µm and implemented on GaAs as a substrate material with relative permittivity of 12.9. The electrostatic and electromagnetic analyses of the designed RF-MEMS Switch have been performed using Ansoft High frequency structure simulator (HFSS) electromagnetic simulator tool.
International Journal of Computer and Electrical Engineering, 2013
This paper critically analyses the DC and RF performance of RF MEMS capacitive coupled switches with respect to changing beam geometry. Switches are designed for operation in the range 10-40 GHz. Pull-in analysis of the switch is performed with aluminum, gold, titanium and platinum as the membrane material. Simulation reveals that for the same geometry, actuation voltage of the switch with aluminum beam is 18.75 V and that with platinum beam is 27.1875 V. RF analysis shows that insertion loss as low as 0.2 dB and isolation as high as 60 dB can be achieved by proper switch design. Design and DC analysis of the proposed switch is carried out using CoventorWare 2010 and RF performance by High frequency Structure simulator (Ansoft HFSS) v 13.0
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IEEE Applied Electromagnetics Conference, 2009
RF MEMS are small mechanical devices fabricated by photolithographic processes, which are used for elemental signal processing functions in RF and microwave, frequency circuits. The design of low loss RF MEMS fixed free capacitive switch is explained. The most common RF MEMS control component is a microwave transmission line switch, currently under development for applications requiring low insertion loss, high linearity, moderate switching speeds and low to moderate power. These shunt switches possess a movable metal membrane which pulls down onto a metal dielectric sandwich to form a capacitive switch. These switches exhibit low loss (<0.25 dB at 35 GHz) with good isolation (35 dB at 35 GHz).This paper gives the construction and performance of low loss RF MEMS Fixed Free switches at microwave and millimetre-wave frequencies (0.1 to 100 Ghz) and also describes the improvements in the design of the switch.
A Generalized Capacitance Model of RF MEMS Switch by considering the Fringing Effect
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Movable suspended microstructures are common features of sensors and devices in the field of Micro Electro Mechanical Systems [MEMS]. This paper addresses the study of approach to model the capacitance for the crab-type meander-based RF MEMS shunt switch with etching holes on the beam. The presented report evaluates the parallel-plate capacitance and fringing-field capacitance caused by the etching holes created on the beam and introducing empirical formulae. The capacitance involves a parallel plate and a fringing field. The parallel-plate capacitance term is proposed by the authors of this work; the fringing-field capacitance term is adopted from previous work. The proposed accurate empirical capacitance formulae are derived by curve fitting the simulated values through the commercially available FEM solver. Two existing benchmark models of fringing-field capacitance are used to modify the perforated MEMS switch to obtain the proposed formula. With the existing models and presented formula, the capacitances are computed for a wide range of dimensions; the simulated results of the presented formula are validated with the calculated results. The deviation of the presented formula has an error estimation of ±0.2%. The variation of the capacitance with different dielectric thickness and error is estimated and analyzed for the proposed empirical formula. The proposed formulae are good for the ligament efficiency µ ≤0.5 with thickness >1 µm, and the deviation of error estimation is within ±5%.
Journal of applied …, 2008
A novel circuital model for predicting the microwave response of a shunt connected capacitive RF MEMS coplanar switch is proposed. The numerical values of the lumped elements composing the equivalent circuit are computed by means of a fully analytic approach. In particular, the contribution of resistive and inductive parasitic elements has been evaluated by using closed form expressions. Configurations characterized by different technological solutions have been obtained and modelled.