Low-Voltage and High-Reliability RF MEMS Switch with Combined Electrothermal and Electrostatic Actuation.
TL;DR: In this paper, a laterally actuated Radio Frequency (RF) Microelectromechanical Systems (MEMS) switch is proposed based on a combination of electrothermal actuation and electrostatic latching hold.
Abstract: In this paper, we report a novel laterally actuated Radio Frequency (RF) Microelectromechanical Systems (MEMS) switch, which is based on a combination of electrothermal actuation and electrostatic latching hold. The switch takes the advantages of both actuation mechanisms: large actuation force, low actuation voltage, and high reliability of the thermal actuation for initial movement; and low power consumption of the electrostatic actuation for holding the switch in position in ON state. The switch with an initial switch gap of 7 µm has an electrothermal actuation voltage of 7 V and an electrostatic holding voltage of 21 V. The switch achieves superior RF performances: the measured insertion loss is −0.73 dB at 6 GHz, whereas the isolation is −46 dB at 6 GHz. In addition, the switch shows high reliability and power handling capability: the switch can operate up to 10 million cycles without failure with 1 W power applied to its signal line.
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07 Jan 2022
1 citations
19 Jun 2022
TL;DR: In this paper , a chevron actuator employing stacked composite SOI/SiO layers is proposed to reduce the potential of crosstalk between the switch and DC heater actuator.
Abstract: This work presents the design and fabrication of a chevron (V-shaped) type electro-thermally actuated micro-electromechanical systems (MEMS) actuator aimed for a DC switch structure using the PiezoMUMPs technology. The chevron actuator employs stacked composite SOI/SiO 2 /Al–Cr layers. The potential of crosstalk between the switch and DC heater actuator is mitigated. An oxide (SiO 2 ) layer acts as an interface between the thin film aluminum (Al) heater and a silicon (Si) structural layer that forms the MEMS switch for power switching applications. Preliminary results show that the out-of-plane motion of the proposed design is reduced by more than 10× in comparison to a reference design. The average power consumption during actuation was measured to be ~ 80 mW, with a switching speed of < 35 ms. The switch can sustain up to 350 V at its terminals, enabling it for use in high voltage harsh environments.
1 citations
07 Jan 2022
1 citations
TL;DR: In this article , the authors provide an overview of different optimization techniques, including Finite Difference Time Domain (FDTD), Finite Element Method (FEM), Method of moments (MoM), Taguchi method, Response Surface Method (RSM), Artificial Neural Network (ANN) model and Evolutionary Algorithm (EA) based model with the ANN and EA model being the most efficient due to its capability to handle complex designs and provide accurate predictions.
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TL;DR: In this paper, an analytical model that can accurately predict the performance of a polysilicon thermal flexure actuator has been developed, based on an electrothermal analysis of the actuator, incorporating conduction heat transfer.
Abstract: An analytical model that can accurately predict the performance of a polysilicon thermal flexure actuator has been developed. This model is based on an electrothermal analysis of the actuator, incorporating conduction heat transfer. Heat radiation from the hot arm of the actuator to the cold arm is also estimated. Results indicate that heat radiation becomes significant only at high input power, and conduction heat losses to both the substrate and the anchor are mainly responsible for the operating temperature of the actuator under routine operations. Actuator deflection is computed based on elastic analysis of structures. To verify the validity of the model, polysilicon thermal flexure actuators have been fabricated and tested. Experimental results are in good agreement with theoretical predications except at high input power. An actuator with a 240 µm long, 2 µm thick, 3 µm wide hot arm and a 180 µm long, 12 µm wide cold arm deflected up to 12 µm for the actuator tip at an input voltage of 5 V while it could be expected to deflect up to 22 µm when a 210 µm long cold arm is used.
358 citations
TL;DR: In this article, a process to manufacture single-crystal thermal actuators using silicon fusion bonding and electrochemical etch stop is presented, which permits simultaneous creation of in-plane and out-of-plane thermal actuator together with levers suitable for both directions of actuation.
Abstract: A process to manufacture single-crystal thermal actuators using silicon fusion bonding and electrochemical etch stop is presented. The process permits the simultaneous creation of in-plane and out-of-plane thermal actuators together with levers suitable for both directions of actuation. A final dry-release step is used, permitting the manufacture of MOS or bipolar devices in conjunction with actuators. Out-of-plane actuation of vertically levered devices has been demonstrated. The −3 dB response frequency of out-of-plane actuators is approximately 1000 Hz in air. Novel levered in-plane devices which achieve deflections of up to 200 μm have been fabricated. An estimate of the upper bound of thermal actuator efficiency is presented.
317 citations
TL;DR: In this paper, a clean metal contact resistance model was used to study the contact resistance of microswitches with gold contacts, and the measured contact resistance (measured as a function of contact force) with the characteristics predicted by the model showed approximate agreement.
Abstract: Surface micromachined, electrostatically actuated microswitches have been developed at Northeastern University. Microswitches with gold contacts typically have an initial contact resistance of the order of 0.1 Ω over the first 10 5 cycles of lifetime while cold-switching 4 mA, and have a current handling capability of about 20 mA. In general, the contact resistance decreases over the first few thousand switch cycles, and degrades progressively when the switches are cycled beyond approximately 10 6 cycles. In this work, the microswitch contact resistance is studied on the basis of a clean metal contact resistance model. Comparison of the measured contact resistance (measured as a function of contact force) with the characteristics predicted by the model shows approximate agreement. The discrepancies between the model characteristics and measurements are discussed briefly.
236 citations
TL;DR: In this article, the authors presented a radical departure from the standard RF microelectromechanical systems (MEMS) devices and introduced novel miniature MEMS switched capacitors for RF to millimeter-wave applications, which are around 150 times smaller in lateral dimensions than standard MEMS designs.
Abstract: This paper presents a radical departure from the standard RF microelectromechanical systems (MEMS) devices and introduces novel miniature MEMS switched capacitors for RF to millimeter-wave applications, which are around 150 times smaller in lateral dimensions than standard MEMS designs. The measured capacitance of a single device (l,w,t of 20, 9.5, 0.37 mum), suspended 0.25 mum above the pull-down electrode, is 3.9 and 11.7-12.1 iF (Cr = 3.0-3.1) in the up- and down-state positions, respectively. The measured capacitance ratio of a 4 X 4 array fabricated on quartz substrates and in a coplanar waveguide (CPW) configuration is 3.0 with an electrical Q > 90 at 20 GHz. The miniature MEMS spring constant is very high, and is much less sensitive to residual stress or temperature variations than standard MEMS devices. Dielectric charging simulations show that these devices can withstand a charge density 6.25 times higher than the standard MEMS devices. The mechanical resonant frequency for a gold device is 2.6 MHz and results in a switching time of 200 ns under a 32-V actuation voltage. Preliminary reliability tests at 13 GHz using bipolar actuation (plusmn30 V) and hot power switching have been performed on five 4 times 4 devices at 100 mW for 20 billion cycles, and at 500 mW for 5 billion cycles with no failures. A 4 times 4 array has also been used in the design of a tunable CPW resonator at 19.3 GHz with a 21% tuning range and 1.6-dB insertion loss. The authors believe that miniature MEMS devices will be very useful in the future for high-reliability MEMS and reconfigurable networks.
96 citations
TL;DR: In this article, an mN-level contact and restoring force RF microelectromechanical system metal-contact switch exhibiting high reliability, high linearity, and high power handing for dc-40 GHz applications was presented.
Abstract: This paper presents an mN-level contact and restoring force RF microelectromechanical systems metal-contact switch exhibiting high reliability, high linearity, and high power handing for dc-40-GHz applications. The device, which is insensitive to stress and temperature effects, achieves 1.2-1.5 mN of contact force (per contact) from 80 to 90 V and 1.0 mN of restoring force (per contact). The up-state capacitance is 8 fF, resulting in an isolation of 46, 31, and 14 dB at 1, 6, and 40 GHz, respectively. Measured results show switch resistances of 1-2 Ω and a reliability of >; 100 million cycles at 2-5 W under cold switching at 100 mW under hot-switching conditions, in an unpackaged and standard laboratory environment. Furthermore, the device was tested under prolonged hold-down conditions and demonstrated excellent RF power handling (>;10 W) and dc current handling (>;1 A) capability.
92 citations