Pi-shaped MEMS architecture for lowering actuation voltage of RF switching (original) (raw)
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A New Electrostatically Actuated Low Voltage RF Mems Switch
European Scientific Journal, 2013
This paper describes the design and simulation of a new low voltage electrostatically actuated RF MEMS switch. The switch structure is designed in such a way that, the inherent limitation of electrostatic actuation is relaxed and the actuation voltage is as low as 3.5 V. The idea is to using a two-step electrostatic actuation mechanism instead of conventional two parallel plate electrostatic actuators. In fact the gap between switch and transmission line is reduced in two steps. In order to investigate the usefulness of the proposed idea, both mechanically and electromagnetically, FEM simulations are carried out and satisfactory results are obtained. The RF characteristics of the switch are as follow; Isolation -12 dB at 30 GHz, Insertion Loss -0.08dB at 30 GHz and return loss was below -20 dB at 30 GHz. The proposed switch in this paper can be a promising choice for low voltage high performance RF MEMS switches.
IET Circuits, Devices & Systems
In this study, a step-down structured switch is designed and compared with and without optimised dimensions to increase the isolation and to lower the pull-in-voltage with respective electromechanical and electromagnetic characteristics. The optimised switch is designed to operate only in K-band frequencies with the high isolation of −54.17 dB at the centre frequency of 22 GHz. The antenna using MEMS switch exhibits a frequency shift of 1.5 GHz from the first case to the second case and 7.4 GHz in the third case due to change in radiating length of patch antenna operating at different ON/OFF combinations of switches whereas the antenna with PIN diode shifts the frequency approximately same, but the low isolation of PIN diode makes it less immune to noise.
Novel RF-MEMS capacitive switching structures
32nd European Microwave Conference, 2002, 2002
This paper reports on novel RF-MEMS capacitive switching devices implementing an electrically floating metal layer covering the dielectric to ensure intimate contact with the bridge in the down state. This results in an optimal switch down capacitance and allows optimisation ofthe down/up capacitance ratio all that are not possible with standard capacitive switches. Simulation data and measurement results are presented clearly indicating the improvedperformance characteristics compared to standard RF-MEMS capacitive switches, in the frequency range from I to 30 GHz. Down/up capacitance ratios higher than 450 have been measured, an improvement of a factor 34 over standard designs with equal size and using the same materials.
A Low Voltage Mems Structure for RF Capacitive Switches
Progress In Electromagnetics Research, 2006
A novel structure for the capacitive micromachined switches with low actuation voltage is proposed. In this structure both contact plates of the switch are designed as displaceable membranes. Two structures with similar dimensions and conditions, differing on only the number of the displaceable beams are analytically investigated as well as simulated using ANSYS software. The obtained results indicate about 30% reduction in actuation voltage from the conventional single beam to our proposed double beam structure. The stress on the beam due to the actuation voltage is also reduced increasing the switching life time. The dynamic simulation results in switching time of 6.5 µsec compared to the 8.9 µsec of the analytical results. It can be implemented by the well established surface micromachining for RF applications.
Fabrication and characterisation of RF MEMS capacitive switches tuned for X and Ku bands
International Journal of Mechatronics and Automation, 2018
Microelectromechanical systems (MEMS) capacitive switches discussed in this paper employ electrostatic actuation to perform switching. Capacitive switches employ inductive tuning for excellent switching characteristics in X and Ku bands. Employing inductive tuning is found to increase the switch beam inductance by a few tens of pico-henry. This enhances the Q factor and enables tuning of isolation over a narrow band of frequencies. Beam inductance can be extracted from the simulated isolation characteristics of the switch by curve fitting. This paper presents design, fabrication and characterisation of inductive tuned MEMS capacitive switches tuned for X and Ku bands. The devices are fabricated on high resistive (10 KΩ) silicon substrate by a five mask process. The characterisation of the fabricated devices are conducted using Cascade probe station and high frequency Power network analyser. Characterisation results show an actuation voltage of 18.5 volts. The insertion-loss and isolation are better than 0.5 dB and-40 dB respectively in the 8-18 GHz band.
Design and optimization of a low-voltage shunt capacitive RF-MEMS switch
2014 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS (DTIP), 2014
This paper presents the design, optimization and simulation of a radio frequency (RF) micro-electromechanical system (MEMS) switch. The device is a capacitive shuntconnection switch, which uses four folded beams to support a big membrane above the signal transmission line. Another four straight beams provide the bias voltage. The switch is designed in 0.35µm complementary metal oxide semiconductor (CMOS) process and is electrostatically actuated by a low pull-in voltage of 2.9V. Taguchi Method is employed to optimize the geometric parameters of the beams, in order to obtain a low spring constant and a robust design. The pull-in voltage, vertical displacement, and maximum von Mises stress distribution was simulated using finite element modeling (FEM) simulation-IntelliSuite v8.7 ® software. With Pareto ANOVA technique, the percentage contribution of each geometric parameter to the spring constant and stress distribution was calculated; and then the optimized parameters were got as t=0.877µm, w=4µm, L1=40µm, L2=50µm and L3=70µm. RF performance of the switch was simulated by AWR Design Environment 10 ® and yielded isolation and insertion loss of-23dB and-9.2dB respectively at 55GHz.
Design and Investigation of RF MEMS Switch
2009
In the last 5-10 years, the high frequency (RF) applications of MicroElectroMechanical Systems (MEMS) devices have reached significant progress, because of their low price, technology, matched with the ordinary microelectronic technologies, good RF parameters and yield. The process of research, investigation and design of RF MEMS switch are presented. The results from this process, in connection with the design of ordinary RF coplanar transmission line, interrupted RF coplanar transmission line and their combination with a contacting metal electrode are shown.
DESIGN OF NON-UNIFORM SHAPED RF MEMS SWITCH
TJPRC, 2013
In this paper, we present aNovel Non-uniform shapedcantilever based DC contact RF MEMS switch. This switch can be employedfor various microwave applications in frequency range of DC-10GHz as it shows excellent RF characteristics. The design is optimized in the terms of electrostatic actuation mechanism, which included switch beam thickness, beam gap and materials. Also the due to its optimized shape and size of contact geometry and material ensures the high reliability, high isolation and very low insertion loss. The main features of our switch aresimplicity of structure, reliability of contact, excellent RF characteristics, low actuation voltage and excellent figure of merit. The pull-in voltage, contact force and S-parameters are analyzed with software such as Coventorware. Various Switching parameters areanalyzed for the performance of the switch in terms of switching speed and power consumption. The paper briefly outlines the Design of RF MEMS switches and also focuses on the research efforts that have gone into maturing the technology.
Design and Simulation of Capacitive RF MEMS Switches using Tuned Dual Beam
2013
A low actuation voltage RF MEMS shunt capacitive switch has been designed and simulated for use in X-band (8-12GHz) applications. The MEMS switch is a freely moving membrane over coplanar waveguide. Double meander structure of tuned dual beam is used here to improve the isolation of switch. Actuation is achieved by using electrostatic mechanism because of its low power consumption, small size and less switching time. Simulation using CoventorWare shows that the actuation voltage for switch is 4.8V to 5.2V and up-state and downstate capacitance of 38fF and 3pF respectively. Spring constant for beam is 3.57N/m. HFSS simulation reveals that insertion loss is in the range of 0.01-0.02dB and up-state return loss better than -15dB in Xband. The switch offers a down-state isolation of 50dB at 10GHz.
Design of H-shaped low actuation-voltage RF-MEMS switches
2006 Asia-Pacific Microwave Conference, 2006
Low actuation-voltage and high reliable microelectromechanical systems (MEMS) shunt capacitive and shunt resistive switches are in this paper proposed. Electrostatic-mechanical coupling using finite element method (FEM) and full-wave electromagnetic (EM) analyses have been performed. The mechanical design of a low spring-constant switch structure has been optimized by calculating the dependence of the actuation voltage on the membrane shape, material properties and geometrical sizes. The proposed switches, based on Al metallization membrane, show a pull-in voltage around 7 and 13 Volts with 0 and 20 MPa residual stresses, respectively. The simulated insertion losses are less than 0.25 dB up to 40GHz with a return loss of about 20 dB in the ONstate. The isolations in the OFF-state for the capacitive-switch are greater than 20 and 35 dB at 12 and 40 GHz, respectively. The shunt resistive switch theoretically works from zero frequency with isolation greater than 25 dB up to 40 GHz. The fabrication of those switches is compatible with standard CMOS technology and they are in process. Index Terms -Low-actuation voltage, MEMS, Pull-in, RF MEMS switch.