ARTIFICAL NEURAL NETWORKS IN RF MEMS SWITCH MODELING

The increased growth of the applications of RF MEMS switches in modern communication systems has created an increased need for their accurate and efficient models. Artificial neural networks have appeared as a fast and efficient modeling tool providing similar accuracy as the standard commercial simulation packages. This paper gives an overview of the applications of artificial neural networks in modeling of RF MEMS switches, in particular of the capacitive shunt switches, proposed by the authors of the paper. Models for the most important switch characteristics in electrical and mechanical domains are considered, as well as the inverse models aimed to determine the switch bridge dimensions for given requirements for the switch characteristics

Artificial Neural Network based Design of RF MEMS Capacitive ShuntSwitches

Artificial neural networks (ANNs) have appeared as a very efficient alternative to time consuming full-wave simulations of electrical characteristics of RF MEMS. In this paper, a new ANN based method to be used in the design of RF MEMS devices is proposed. ANNs are trained to model dependence of the scattering parameters and the resonant frequency of an RF MEMS switch on the switch geometrical parameters, as well as to perform the opposite procedure, i.e., to determine values of the geometrical parameters to achieve the desired electrical resonant frequency. The developed models can be used for fast simulation and optimization of the switch characteristics replacing time consuming procedures in full-wave simulators, which leads to a significant reduction of time needed for the device design.9 halama

A low contact-resistance winged-bridge RF-MEMS series switch for wide-band applications

A MEMS ohmic series switch with a winged bridge has been designed, fabricated and tested. Based on the analysis of the various factors affecting the contact resistance of the switch, a new geometry has been adopted for the bridge, which involves the presence of two side wings and an appropriate number of bumps. An accurate electromagnetic analysis has been employed to identify a proper layout to reduce the losses due to bias lines and internal mismatch. In this manner, an on-state return loss better than 25 dB along with an off-state isolation better than 20 dB in the frequency range 0-30 GHz has been demonstrated. In reliability and power handling tests the switches have been actuated up to 108 cycles without any performance degradation and up to 109 cycles with an increase of 0.6 dB in the insertion loss (RF cold switching). Power handling tests have also been performed up to an input power of 5 W, showing a very linear Pout/Pin response and no stiction or failure due to other mechanisms of the MEMS switch

Development of High Con Coff Ratio RF MEMS Shunt Switches

Abstract. This paper reports on the successive improvements introduced in the shunt switches fabricated with the RF MEMS multiuser technology platform available at FBK. In the course of a multiyear development several technological features and design methods have been made available to enhance the operation of capacitive switches. This work analyzes their effects by reviewing the behaviour of the FBK capacitive switches at three different stages of this optimization process. Improvements have been assessed by means of DC electromechanical characterizations, which use a simple quasistatic C-V measurement to extract the switch actuation voltage and the capacitance in the on and off states (Con and Coff) and RF measurements. The addition of a floating metal layer into the process fow has allowed a great increase of the switch on state capacitances, getting Con/Coff ratios of 200, up to 50 times greater than the ones obtained for the same structures without this feature

Technological and design improvements for RF MEMS shunt switsches

This paper reports on the successive improvements introduced in the shunt switches fabricated with the RF MEMS multiuser technology platform available at FBK-irst. In the course of a multiyear development several technological features and design methods have been made available to enhance the operation of capacitive switches. This work analyzes their effects by reviewing the behaviour of the FBK-irst capacitive switches at three different stages of this optimization process. Improvements have been assessed by means of DC electromechanical characterizations, which use a simple quasistatic C-V measurement to extract the switch actuation voltage and the capacitance in the on and off states (Con and Coff) and RF measurements. The addition of a floating metal layer into the process flow has allowed a great increase of the switch on state capacitances, getting Con/Coff ratios of 200, up to 50 times greater than the ones obtained for the same structures without this feature

Compact 12x12 Switch Matrix integrating RF MEMS switches in LTCC hermetic packages

A 12×12 Switch Matrix Unit featuring silicon RF MEMS assembled on LTCC boards has been developed under a Contract with the European Space Agency (ESA) for satellite communication application. The Switch Matrix is a complete Engineering Model unit, housed in a mechanical box in aluminum with RF coaxial connectors and DC connectors for powering and commanding. To the authors’ knowledge, it is the first complex equipment realized in Europe exploiting the advanced features of the RF MEMS and multilayer LTCC technology to achieve a significant mass and size reduction. Full wave simulations of entire structure are reported, as well as test results. Their agreement is good up to the satellite downlink C-band (3.7–4.2 GHz). An insertion loss of -20dB, return loss of -10dB and isolation of 40–45dB have been measured. The matrix is passive (not provided with amplifiers), having a DC power consumption of less than half watt due to the digital command circuitry