An investigation in optimising RF MEMS switching for integrated mobile wireless systems

Radio Frequency Micro Electromechanical Systems (RF MEMS) technology is used to help switch, filter or tune signals from Direct Current to RF. RF MEMS switches are known to provide good isolation with low insertion loss and can be applied to a wide range of frequencies with almost no power consumed to drive them, which provides an advantage for integrated mobile wireless systems. Despite the benefits, RF MEMS switches have not seen a rapid development for commercialisation in the integrated mobile wireless systems market because of reliability issues and high actuation voltage requirements, which makes additional voltage drive circuitry necessary. This in turn makes the overall switch larger in size. Due to these shortfalls, this research undertakes an investigation by optimising RF MEMS switches. This thesis presents an RF MEMS switch for use in mobile systems, based on the optimisation of a cantilever, ohmic type switch. The optimisation resulted in five major iterations, each providing improvements over the cantilever. The final optimised iteration researched is the ‘S’ Shaped, Split Pivot, Seesaw, Double-Pole DoubleThrow (DPDT) switch. This optimised design provides capabilities of high RF isolation. It provides low actuation voltages (by using ‘Delta Plates’). The switch takes advantage of an ‘S’ Shaped, Split Pivot, allowing the pivot to flex with less force, which reduces actuation voltage. The optimised designs provide a selection of switches, which take advantage of low voltages used by mobile systems (i.e. ≤ 5V). The ‘S’ shaped pivot has a lower von mises stress (15MPa), which is below the yield strength of copper (70 MPa), allowing the design to return to its original state without deforming. This proved a 97.8% reduction in von mises stress over the cantilever and a reduction of actuation voltage from 30V down to 1.13V. The functionality of the switch is increased by 4 times to provide DPDT switching over the cantilever’s SinglePole Single-Throw (SPST) switching. Also, the ‘S’ Shaped, Split Pivot, Seesaw DPDT switch, maintains a higher isolation over its predecessor (cantilever) with an average isolation of -102.89 dB over a frequency range from 5GHz to 45GHz. This provides a 246% improvement to that of the cantilever’s isolation. A Finite Element Analysis approach was used, with mathematical analysis to validate the Intellisuite simulation tool. A secondary validation was conducted, with known practical cantilever results against the Intellisuite Simulation tool for the electromechanical characteristics of the switch. The electromagnetics (EM) characteristics of the switch were also validated, with the Computer Simulation Technology (CST) electromagnetic simulation tool, against the cantilever’s practical results. The optimisation followed a linear approach, with each component of the switch having incremental improvements, such as: Contacts, Beam, Electrostatic Parallel Plates and Pivots. The research has discovered that RF MEMS switches (i.e. cantilevers) are larger than the micro size, require high actuation voltages and have increased von mises stress. The optimisations focused on four areas of improvements to the characteristics of the switch and addressed them as follows: reducing actuation voltage, decreasing von mises stress, increasing isolation of the contacts and expanding functionality.

[1]  Experimental analysis and modeling of the mechanical impact during the dynamic pull-in of RF-MEMS switches , 2010, The Eighth International Conference on Advanced Semiconductor Devices and Microsystems.

[2]  N. McGruer,et al.  Mechanical, Thermal, and Material Influences on Ohmic-Contact-Type MEMS Switch Operation , 2006, 19th IEEE International Conference on Micro Electro Mechanical Systems.

[3]  L. Vietzorreck.  EM Modeling of RF MEMS , 2006, EuroSime 2006 - 7th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems.

[4]  H. Okazaki,et al.  A 900/1500/2000-MHz triple-band reconfigurable power amplifier employing RF-MEMS switches , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[5]  Herman F. Nied,et al.  Microwave intermodulation technique for monitoring the mechanical stress in RF MEMS capacitive switches , 2008, 2008 IEEE MTT-S International Microwave Symposium Digest.

[6]  H. D. L. Santos.  Introduction to Microelectromechanical(MEM)Microwave Systems , 1999 .

[7]  A. Kingon,et al.  Comparison of Au and Au–Ni Alloys as Contact Materials for MEMS Switches , 2009, Journal of Microelectromechanical Systems.

[8]  Herbert Shea.  Reliability of MEMS for space applications , 2006, SPIE MOEMS-MEMS.

[9]  J. Oberhammer,et al.  Active Opening Force and Passive Contact Force Electrostatic Switches for Soft Metal Contact Materials , 2006, Journal of Microelectromechanical Systems.

[10]  Gabriel M. Rebeiz,et al.  A Stress-Tolerant Temperature-Stable RF MEMS Switched Capacitor , 2009, 2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems.

[11]  Xunjun He,et al.  Design and analysis of a novel low actuation voltage capacitive RF MEMS switches , 2008, 2008 3rd IEEE International Conference on Nano/Micro Engineered and Molecular Systems.

[12]  Xueping Li,et al.  Design and analysis of the micromechanical structure for an electromagnetic bistable RF MEMS switch , 2005, 2005 Asia-Pacific Microwave Conference Proceedings.

[13]  A.S. Holmes,et al.  A novel seesaw-type RF MEMS switch , 2006, MELECON 2006 - 2006 IEEE Mediterranean Electrotechnical Conference.

[14]  D. K. Parsediya.  Deflection and stresses of effective micro-cantilever beam designs under low mass loading , 2016, 2016 International Conference on Electrical Power and Energy Systems (ICEPES).

[15]  Qiao Bai,et al.  Simulation and Optimal Design for RF MEMS Cantilevered Beam Switch , 2009, 2009 ETP International Conference on Future Computer and Communication.

[16]  C.P. Wong,et al.  Lotus effect surface for prevention of microelectromechanical system (MEMS) stiction , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[17]  P. Grabiec,et al.  New approach for a multi-cantilever arrays sensor system with advanced MOEMS readout , 2016, 2016 46th European Solid-State Device Research Conference (ESSDERC).

[18]  A.F. Malik,et al.  Modeling and designing of RF MEMS switch using ANSYS , 2008, 2008 4th International Conference on Emerging Technologies.

[19]  K. Said,et al.  Testing and characterization of a MEMS micro-cantilever system , 2016, 2016 IEEE 59th International Midwest Symposium on Circuits and Systems (MWSCAS).

[20]  J. Lu,et al.  High Power and Reliable SPST/SP3T RF MEMS Switches for Wireless Applications , 2016, IEEE Electron Device Letters.

[21]  G. Meneghesso,et al.  Electrostatic Discharge and Cycling Effects on Ohmic and Capacitive RF-MEMS Switches , 2007, IEEE Transactions on Device and Materials Reliability.

[22]  Yuh-Chung Hu,et al.  Electromechanical behavior of the curled cantilever beam , 2009 .

[24]  A. Kouzani,et al.  Impact of carbon material on RF MEMS switch , 2013, 2013 21st Iranian Conference on Electrical Engineering (ICEE).

[25]  Samir D. Mhaske,et al.  SPMT, MPST RF MEMS switch using multiplexer approach , 2015, 2015 International Conference on Communications and Signal Processing (ICCSP).

[26]  B. Reig,et al.  Key improvements of the MEMS switch lifetime thanks to a dielectric-free design and contact reliability investigations in hot/cold switching operations , 2013, 2013 IEEE International Reliability Physics Symposium (IRPS).

[27]  Rudra Pratap,et al.  Material selection for MEMS devices , 2007 .

[28]  Hee-Chul Lee,et al.  Piezoelectrically actuated RF MEMS DC contact switches with low voltage operation , 2005 .

[29]  R. Plana,et al.  Multi-Physical Characterization of Micro-Contact Materials for MEMS Switches , 2010, 2010 Proceedings of the 56th IEEE Holm Conference on Electrical Contacts.

[30]  Norhayati Soin,et al.  Simulation and analysis of actuation voltage of electrostatically actuated RF MEMS cantilever switch , 2015, 2015 International Conference on Smart Sensors and Application (ICSSA).

[31]  Richard Phillips Feynman,et al.  Infinitesimal machinery , 1993 .

[32]  K. Y. Chan,et al.  Investigation of residual stress effects and modeling of spring constant for RF MEMS switches , 2009, 2009 Mediterrannean Microwave Symposium (MMS).

[33]  Haslina Jaafar,et al.  Design and simulation of high performance RF MEMS series switch , 2011, 2011 IEEE Regional Symposium on Micro and Nano Electronics.

[34]  M. Ashby.  MULTI-OBJECTIVE OPTIMIZATION IN MATERIAL DESIGN AND SELECTION , 2000 .

[35]  G.E. Moore,et al.  Cramming More Components Onto Integrated Circuits , 1998, Proceedings of the IEEE.

[36]  See-saw Type RF MEMS Switch with Fine Gap Vertical Comb , 2006, 2006 IEEE International Conference on Semiconductor Electronics.

[37]  Gabriel M. Rebeiz.  RF MEMS: Theory, Design and Technology , 2003 .

[38]  Peter G. Steeneken,et al.  Performance limits of MEMS switches for power electronics , 2012, 2012 24th International Symposium on Power Semiconductor Devices and ICs.

[39]  Hyeon Cheol Kim,et al.  Single pole four throw RF MEMS switch with double stop comb drive , 2008, 2008 IEEE 21st International Conference on Micro Electro Mechanical Systems.

[40]  I. Kofsky.  Atwood's Machine and the Teaching of Newton's Second Law , 1951 .

[41]  Gabriel M. Rebeiz,et al.  RF MEMS Capacitive Switches for Wide Temperature Range Applications Using a Standard Thin-Film Process , 2011, IEEE Transactions on Microwave Theory and Techniques.

[42]  J.C.M. Hwang.  Reliability of Electrostatically Actuated RF MEMS Switches , 2007, 2007 IEEE International Workshop on Radio-Frequency Integration Technology.

[43]  Chaitali Anil Muley,et al.  Modelling of cantilever based MEMS RF switch , 2013, 2013 Fourth International Conference on Computing, Communications and Networking Technologies (ICCCNT).

[44]  T. Shanmuganantham,et al.  Design and analysis of RF MEMS switch with π-shaped cantilever beam for wireless applications , 2016, 2016 International Conference on Emerging Technological Trends (ICETT).

[45]  A. Hariri,et al.  Modeling of Wet Stiction in Microelectromechanical Systems (MEMS) , 2007, Journal of Microelectromechanical Systems.

[46]  R. Nilavalan,et al.  Analysis and design of an all metal in line series ohmic RF MEMS switch for microwave applications , 2010, 2010 Symposium on Design Test Integration and Packaging of MEMS/MOEMS (DTIP).

[47]  Design and fabrication of low-insertion loss and high-isolation CMOS-MEMS switch for microwave applications , 2010, 2010 5th International Microsystems Packaging Assembly and Circuits Technology Conference.

[48]  Sufian Yousef,et al.  Simulation of an RF MEMS Double-Pole Double-Throw Switch Using Novel Seesaw Design , 2014 .

[49]  Adele E. Schmitz,et al.  Surface-micromachined RF MEMs switches on GaAs substrates , 1999 .

[50]  Fabienne Pennec,et al.  RF MEMS electrical contact resistance calculation using mechanical contact simulations and analytical models , 2009 .

[51]  Chang Han Je,et al.  A low-loss single-pole six-throw switch based on compact RF MEMS switches , 2005, IMS 2005.

[52]  Premila Manohar,et al.  Design and simulation of multi-beam RF MEMS varactor , 2014, International Conference on Circuits, Communication, Control and Computing.

[53]  A. Menz,et al.  Micromechanical silicon RF switch with electroplated solid contacts for high reliability , 2012, 2012 7th European Microwave Integrated Circuit Conference.

[54]  Sufian Yousef,et al.  Development of a double-pole double-throw radio frequency micro electro-mechanical systems switch using an ‘S’ shaped pivot , 2017, Int. J. Syst. Assur. Eng. Manag..

[55]  Zewen Liu,et al.  Copper-based multimetal-contact RF MEMS switch , 2016, 2016 17th International Conference on Electronic Packaging Technology (ICEPT).

[56]  C. V. Nielsen,et al.  Modeling of Thermo-Electro-Mechanical Manufacturing Processes , 2013 .

[57]  D. Peyrou,et al.  A New Methodology For RF MEMS Contact Simulation , 2008, EuroSimE 2008 - International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Micro-Systems.

[58]  Chongdu Cho,et al.  Deflection, Frequency, and Stress Characteristics of Rectangular, Triangular, and Step Profile Microcantilevers for Biosensors , 2009, Sensors.

[59]  Jin Lin.  The ultra-wideband RF MEMS single-pole-four-throw switch , 2016, 2016 International Symposium on Antennas and Propagation (ISAP).

[60]  Jong-Uk Bu,et al.  Contact materials and reliability for high power RF-MEMS switches , 2007, 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS).

[61]  Richard P. Feynman.  There's plenty of room at the bottom [data storage] , 1992, Journal of Microelectromechanical Systems.

[62]  Lawrence E. Larson,et al.  Microactuators for GaAs-based microwave integrated circuits , 1991, TRANSDUCERS '91: 1991 International Conference on Solid-State Sensors and Actuators. Digest of Technical Papers.

[63]  Walter Bacher,et al.  The LIGA technique and its potential for microsystems-a survey , 1995, IEEE Trans. Ind. Electron..

[64]  M. Pecht,et al.  A novel electrostatic Radio Frequency Micro Electromechanical Systems (RF MEMS) with Prognostics function , 2012, 2012 IEEE 62nd Electronic Components and Technology Conference.

[65]  Zlatica Marinkovic,et al.  Efficient modelling of an RF MEMS capacitive shunt switch with artificial neural networks , 2013, 2013 International Symposium on Electromagnetic Theory.

[66]  J. Bryzek,et al.  Micromachines on the march , 1994, IEEE Spectrum.

[67]  Yasser Mafinejad,et al.  Design and simulation of a low voltage wide band RF MEMS switch , 2009, 2009 IEEE International Conference on Systems, Man and Cybernetics.

[68]  Anis Nurashikin Nordin,et al.  Theoretical and simulated investigation of dielectric charging effect on a capacitive RF-MEMS switch , 2016, 2016 IEEE International Conference on Semiconductor Electronics (ICSE).

[69]  Jaewoo Lee,et al.  A single-pole 6-throw (SP6T) antenna switch using metal-contact RF MEMS switches for multi-band applications , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[70]  I.D. Robertson,et al.  Single-Pole Eight-Throw RF MEMS Rotary Switch , 2006, Journal of Microelectromechanical Systems.

[71]  Supriya B. Asutkar,et al.  A novel approach for optimized design of RF MEMS capacitive switch , 2016, 2016 2nd International Conference on Advances in Electrical, Electronics, Information, Communication and Bio-Informatics (AEEICB).

[72]  Thomas J. R. Hughes,et al.  Improved numerical dissipation for time integration algorithms in structural dynamics , 1977 .

[73]  Z. Stanimirović,et al.  Mechanical Properties of MEMS Materials , 2009 .

[74]  Akira Akiba,et al.  A fast and low actuation voltage MEMS switch for mm-wave and its integration , 2010, 2010 International Electron Devices Meeting.

[76]  G. Schrag,et al.  Long-term investigations of RF-MEMS switches on failure mechanisms induced by dielectric charging , 2014, 2014 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS (DTIP).

[77]  Clark T.-C. Nguyen.  RF MEMS in wireless architectures , 2005, Proceedings. 42nd Design Automation Conference, 2005..

[78]  S. Pranonsatit,et al.  Rotary RF MEMS Switch Based on the Wobble Motor Principle , 2006, 19th IEEE International Conference on Micro Electro Mechanical Systems.

[80]  Sufian Yousef,et al.  RF MEMS DPDT Switch Using Novel Simulated Seesaw Design , 2013 .

[81]  H. Nathanson,et al.  The resonant gate transistor , 1967 .

[82]  Joel A. Kubby.  A Guide to Hands-on MEMS Design and Prototyping: Fluidic MEMS , 2011 .

[83]  Pierre Blondy,et al.  Symmetric and Compact Single-Pole Multiple-Throw (SP7T, SP11T) RF MEMS Switches , 2015, Journal of Microelectromechanical Systems.

[84]  T. Sharma,et al.  Review of Mechanical Modelling of Fixed-Fixed Beams in RF MEMS Switches , 2013, 2013 Third International Conference on Advanced Computing and Communication Technologies (ACCT).

[85]  Kamal J. Rangra,et al.  Design optimization of RF MEMS SP4T and SP6T switch , 2009, 2009 International Semiconductor Conference.

[86]  Lawrence E. Larson,et al.  Micromachined microwave actuator (MIMAC) technology-a new tuning approach for microwave integrated circuits , 1991, IEEE 1991 Microwave and Millimeter-Wave Monolithic Circuits Symposium. Digest of Papers.

[87]  P N Scharbach,et al.  A Dynamical Theory of the Electromagnetic Field , 1983 .

[88]  Anis Nurashikin Nordin,et al.  Design and analysis of a low-voltage electrostatic actuated RF CMOS-MEMS switch , 2013, RSM 2013 IEEE Regional Symposium on Micro and Nanoelectronics.

[89]  M. Kaynak,et al.  Electro-thermo-mechanical analysis of a BiCMOS embedded RF-MEMS switch for temperatures from −55°C to + 125°C , 2013, 2013 IEEE 13th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems.

[90]  Dimitri Linten,et al.  Behavior of RF MEMS switches under ESD stress , 2010, Electrical Overstress/Electrostatic Discharge Symposium Proceedings 2010.

[91]  Lianjun Liu.  High Performance RF MEMS Series Contact Switch - Design and Simulations , 2007, 2007 Proceedings 57th Electronic Components and Technology Conference.

[92]  Hee-Moon Jeong,et al.  Variable pivot seesaw actuated RF MEMS switch for reconfigurable system application , 2007, 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS).

[93]  Takeshi Fujiwara,et al.  An RF MEMS switch for 4G Front-Ends , 2013, 2013 IEEE MTT-S International Microwave Symposium Digest (MTT).

[94]  R. Ramer,et al.  RF MEMS Switch with low stress sensitivity and low actuation voltage , 2009, 2009 IEEE Antennas and Propagation Society International Symposium.

[95]  Sufian Yousef,et al.  SIMULATED RF MEMS DOUBLE-POLE DOUBLE-THROW SWITCH USING A NOVEL SEESAW STRUCTURE , 2014 .

[96]  Kieran Delaney,et al.  Modeling, simulation and validation of the dynamic performance of a single-pole single-throw RF-MEMS contact switch , 2011, 2011 12th Intl. Conf. on Thermal, Mechanical & Multi-Physics Simulation and Experiments in Microelectronics and Microsystems.