Low-cost low actuation voltage copper RF MEMS switches

This paper presents the design, fabrication and testing of capacitive RF MEMS switches with a new, low processing cost dielectric layer on high-resistivity silicon substrate. The dielectric can be spun on the wafer and its parameters (dielectric constant and loss) can be controlled during fabrication to achieve the desired values. Both bridge- and cantilever-type switches were fabricated on high-/spl rho/ silicon substrate using a simple low cost four-mask process. Measured results are presented.

This paper presents the design and RF characterization of micro electromechanical system (MEMS) switches realized on Elevated Coplanar waveguide for high-speed applications. The capacitive air gap between signal line and the cantilever is 1um. The lowest actuation voltage obtained is 6V. The insertion loss of switch and its associated transmission line is −0.31dB (mainly contributed by the transmission line itself) and the isolation was around −21.67dB at 40GHz.

RF MEMS capacitive switch on semi-suspended CPW using low-loss high-resistivity silicon substrate

Notice of Violation of IEEE Publication Principles<br><br>"Both the authors and the Editor-in-Chief of Volume 13, number 3 of the IEEE/ASME JMEMS (June 2004, pp. 542-549) of the paper numbered JMEMS 1041 have agreed that this paper, Ka-Band Distributed MEMS Phase Shifters on Silicon Using AlSi Suspended Membrane," should not have been published. The paper would have been withdrawn had this fact been discovered before the IEEE/ASME JMEMS print date for June 2004. The authors have indicated that they will work to provide a new version their paper that will be considered for publication if it is submitted in the future. For help in coming to this decision, I would like to thank those concerned individuals, including the authors, JMEMS editors, and highly respected researchers in the MEMS and microwave communities who contributed their time and consideration to help us assure the integrity of our journal." <br><br>Richard S. Muller, Editor-in-Chief, IEEE/ASME JMEMS<br><br>This paper presents the design, fabrication, and testing of distributed MEMS phase shifters for Ka-band communication systems. The phase shift can be obtained by changing MEMS bridge capacitors located periodically over the transmission line. Simulation results of phase shifters with various structural parameters are analyzed to develop the optimized designs. The phase shifters are fabricated on the high-resistivity silicon substrate, using suspended AlSi bridge membrane. The measured results demonstrate a phase shift of 286° at 36 GHz with the actuation voltage of 25 V, and a return loss better than 10 dB over 0-40 GHz band. In addition, lifetimes of 3×10/sup 6/ cycles have been achieved for the fabricated phase shifter with all MEMS bridges held to be valid. It shows that AlSi alloy has a nice compromise between strength and resilience. <br/> This paper presents the design, fabrication, and testing of distributed MEMS phase shifters for Ka-band communication systems. The phase shift can be obtained by changing MEMS bridge capacitors located periodically over the transmission line. Simulation results of phase shifters with various structural parameters are analyzed to develop the optimized designs. The phase shifters are fabricated on the high-resistivity silicon substrate, using suspended AlSi bridge membrane. The measured results demonstrate a phase shift of 286° at 36 GHz with the actuation voltage of 25 V, and a return loss better than 10 dB over 0–40 GHz band. In addition, lifetimes of 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> cycles have been achieved for the fabricated phase shifter with all MEMS bridges held to be valid. It shows that AlSi alloy has a nice compromise between strength and resilience.

Micro-electro-mechanical-systems(MEMS) switches have low resistive loss, negligible power consumption, good isolation and high power handling capability compared with semiconductor switches. Lifetime of capacitive shunt switches strongly depends on the actuation voltage so low voltage switches is necessary to enhance its performance as well as to broaden its application area. This paper presents the design and simulation of low voltage capacitive shunt MEMS switches together with its RF performance for high frequency applications. The low voltage switches are realized by lowering the spring constant of the beam using serpentine spring designs together with large capacitive area so as to achieve the good RF performance as well. The pull-in voltage is analyzed with commercial CAD finite element analysis software CoventorWare. The electromagnetic performance in terms of scattering parameters, insertion loss, and isolation are analyzed with software Ansoft HFSS10. The switches achieved insertion loss $$<$$ < 0.47 dB in on state from 2 to 40 GHz; it provided better than 25 dB isolation in off state with a capacitance ratio of 94---96. The actuation voltage as low as 1.5 V with actuation area $$110\,\times \,100\,\upmu \mathrm{m^2}$$ 110 × 100 μ m 2 along with good RF performance is reported. The design parameter optimization including selection of appropriate number of meanders and its width found to be one of the most sensitive factors affecting the spring stiffness and actuation voltage.

RF MEMS switches provide a low-cost, high performance solution for many RF/microwave applications these switches will be important building blocks for designing phase shifters, switched filters reflector array antennas for military and commercial markets. In this paper, progress in characterizing of THALES capacitive MEMS devices under high RF power is presented. The design, fabrication and testing of capacitive RF MEMS switches for microwave/mm- wave applications on high-resistivity silicon substrate is presented. The switches tested demonstrated power handling capabilities of 1W (30 dBm) for continuous RF power. The reliability of these switches was tested at various power levels indicating that under continuous RF power. In addition a description of the power failures and their associated operating conditions is presented. The PC-based test stations to cycle switches and measure lifetime under DC and RF loads have been developed. Best-case lifetimes of 10¹⁰ cycles have been achieved in several switches from different lots under 30 dbm RF power.

Silicon has many advantages as a microwave substrate material including low cost and a mature technology. The aim of this paper is to evaluate the potential of using high-resistivity silicon as a low-cost low-loss microwave substrate through an experimental comparative study. Coplanar waveguides fabricated on Si, GaAs, and quartz substrates are tested and their characteristics are compared. Microwave spiral inductors and meander lines are also fabricated on various substrates, and their performance is also analyzed. The results demonstrate that the losses of a coplanar transmission line (CPW) realized on high-resistivity (3 k to 7 k /spl Omega/-cm) silicon substrates are comparable to the losses of a CPW realized on a GaAs substrate covered with insulators. Furthermore, measured unloaded Q's of microwave inductive structures on high-resistivity silicon substrates are comparable to the measured unloaded Q's of the same structures on GaAs and on quartz. This paper demonstrates that high-resistivity Si can be used as a microwave substrate.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

This paper presents the design, fabrication and testing of capacitive RF MEMS switches for microwave/mm- wave applications on high-resistivity silicon substrate or glass. The feasibility study and demonstrator fabrication of a new concept of reflector network using MEMS switch based phase-shifters concept for space antennas is presented. These switches can be accurately modeled using 3-D static solvers. The loss in the up-state position is equivalent to the CPW line loss and is 0.1-0.3 dB at 10-40 GHz. It is seen that the capacitance, inductance and series resistance can be accurately extracted from DC-40 GHz S-parameter measurements. The reflector array antennas utilization for phase control avoids the use of very expensive directive antennas and covers a very large frequencies range. We will deal with the configuration, the composition and arrangement of MEMS switches, used to control the phase shift of the electromagnetic wave reflected by each elementary cell.

Three RF switches and a phase shifter are proposed using the conductive bridging random access memory (CBRAM) technique. The fabrication process is developed with the Nafion membrane on a high-resistivity silicon substrate. The equivalent circuit model is established for each memristive RF switch. The proposed switches and the phase shifter have been validated by the good agreement achieved among the simulated, measured, and modeled results. The experimental results show that the series planar switch has the ON-state insertion loss (IL) below 1.69 dB and the OFF-state isolation over 25 dB up to 10 GHz, with the actuation voltages of 6.1~7.8/−1.5~−2 V. The parallel metal–insulator–metal (MIM) switch has the small ON-state IL below 0.45 dB and the OFF-state isolation over 18.4 dB when biased with 0.8~3.7/−0.5~−0.9 V. The series MIM switch has the ON-state IL below 0.61 dB and the OFF-state isolation over 21.9 dB with 0.7~2.3/−0.5~−0.9 V. The series MIM switch shows a good comprehensive performance of low actuation voltage, good uniformity, low IL, moderate isolation, and independent control. The phase shifter is realized with four series MIM switches, which provides a phase shift of 45° ± 5° from 3.8 to 4.3 GHz with the in-band IL of 2.25 dB. Compared with the conventional RF switchable devices, the proposed devices have the advantages of nonvolatility and low power consumption. Without depending on the electron beam lithography process and high-temperature phase change, the proposed technique is promising for reconfigurable RF circuits with mass production and feasibility to various substrates.

Capacitive RF MEMS switches present several drawbacks such as high actuation voltages, slow switching times and time-varying performances, due to the deterioration of both their mechanical and electrical properties. Such characteristics justify the interest of the scientific community on the development of accurate measurement techniques to monitor the dynamic behavior of capacitive MEMS switches during continuous actuations. In this paper, a novel measurement system devoted to the time-domain characterization of capacitive MEMS switches is proposed. Moreover, an electrical model for such devices is introduced and its lumped elements are characterized by means of measurement results. The proposed test-bench allows to measure the modulus and the phase of both the incident and the reflected signals of a one-port transmission line based, where the port is represented by the capacitive MEMS device. The paper introduces a software tool based on LabVIEWtrade to compute the capacitance and the resistance values of the model as functions of time. In particular the tool transforms the measured signals in the frequency domain to compute the reflection coefficient by means of components depending on the fundamental frequency of the RF signal, thus neglecting spurious frequency components, out-band noise and harmonics due to interferences

We report a study over a wide range of high-K dielectric materials (Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</inf> , HfO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> , TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> …) deposited by different techniques (Evaporation, ALD, PEALD…) for high power RF applications. Main results show that ALD technique is matching the McPherson trend based on thermochemical prediction. Furthermore ALD materials are promising to meet high power requirements for capacitive RF MEMS switches. As a result, Thermal ALD HfO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> was integrated in high power capacitive RF MEMS switches in order to improve their RF performances, power handling and reliability.

This paper presents a novel structure of capacitance shunt type RF switch for 5G applications. The proposed RF MEMS switch is having Cantilever type designed with optimized dimensions to operate in V-band applications. The electromechanical analysis is done by using the COMSOL tool. The actuation voltage of the proposed switch is 10.5 V with the air gap of 1 µm and gold as a beam material. The proposed switch with the meanders and perforations show the scattering parameters in HFSS software such as insertion loss (S12) of − 0.033 dB and return loss (S11) less than − 48 dB and the isolation (S21) calculated in off-state as − 62 dB at 50 GHz.

In this paper, the design of bi-metallic capacitive shunt type RF MEMS switch is carried out and analyzed using FEM tool. The significant accomplishments in this work are the pull-in voltage that is minimized to 4.8 V and fast switching time of 7.2 µs. The upstate capacitance of the switch is observed as 300 fF, down state capacitance as 9.2 pF, which leads to have the capacitance ratio of 30.6. The material utilized for CPW line is Gold (Au) and the dielectric material utilized in between the beam and the CPW transmission line is Silicon Nitride (Si3N4). The electromagnetic characteristics are also analyzed through HFSS software.

This paper explores the usefulness of RF MEMS and reconfigurable antennas in the context of modern communication systems and other applications. Simulation studies on a fractal antennas with switches and phase shifters provide beam steering and beam scanning characteristics. A brief description of the design aspects of two MEMS based coplanar waveguide (CPW) phase shifters for microwave and millimeter wave antenna applications are also provided here. One phase shifter design consists of a unique bilateral interdigital structure on a silicon substrate deposited with a thin film of electrically tunable barium strontium titanate. The dielectric constant of the thin film, and hence the effective permittivity of the transmission line changes by the application of a bias voltage. The second device is a distributed microelectromechanical system (MEMS) phase shifter fabricated on a high resistivity silicon substrate using microstereolithography technique is presented here. The distributed MEMS phase shifter consists of a high-impedance CPW transmission line and several MEMS bridges of uniform height. By applying a voltage the height of these bridges can be adjusted. This results in a variation in the distributed capacitance of the segment of the transmission line, which manifests in the phase shift at the output terminal. The fabrication procedure described here shows significant promise for the use of microstereolithography techniques for RF MEMS devices.

A DC contact series MEMS switch for reconfigurable antenna system application is designed, fabricated, and its RF characteristics are measured. Variable pivot seesaw concept is applied because this design minimize the driving voltage and prevent stiction of membrane. The proposed switch structure is fabricated on the Si wafer, a coplanar waveguide(CPW) signal lines and electrodes are fabricated on the glass wafer. Both wafer are bonded by anodic bonding method. The designed chip size is within 2 mmx2 mm and it is actuated by electrostatic force. Low actuation voltage has been achieved by means of small distance between signal line and membrane using the design scheme, switching is executed in the pull-in range. Minimum actuation voltage is about 10-12 V, isolation is around 50 dB and insertion loss is about 0.25 dB at 2 GHz.