A novel DMTL capacitive switch with electrostatic actuation MAM capacitors

A novel DMTL capacitive switch with electrostatic actuation metal–air–metal (MAM) capacitors is presented. The top board of MAM capacitors will be pulled down together with the switch bridge. It has higher isolation in down-state than DMTL capacitive switch and has lower insert loss and higher self-actuation RF power comparing with MEMS shunt capacitive switch. Two of the novel DMTL capacitive switches are designed for high isolation and high self-actuation RF power, respectively. The calculated result shows that both of the two novel switches have lower insert loss than the MEMS shunt capacitive switch. The self-actuation RF power of them are 4 and 2.4 times that of MEMS shunt capacitive switch, respectively, at the cost of ?6.23 and ?3.54?dB reduction in isolation (30?GHz).     

Design and modeling of a continuously variable piezoelectric RF MEMS switch

A structure for a piezoelectrically actuated capacitive RF MEMS switch that is continuously variable between the ON state and the OFF state has been proposed. The device is based on variable capacitance using a cantilever fixed at both ends that is actuated using a lead zirconate titanate thin film. Because the device is contactless, the reliability issues common in contact-type RF MEMS switches can be avoided. A comprehensive mathematical model has been developed in order to study the performance of the device, and allow for design optimization. Electrical measurements on test structures have been compared with the performance predicted by the model, and the results used to design a prototype RF MEMS switch. The model and simulations indicate the proposed switch structure can provide an insertion loss better than 0.7 dB and an isolation of more than 10 dB between 6 and 14 GHz with an actuation voltage of 22.4 V. The state of the device is continuously variable between the ON state and the OFF state, with a tunable range of capacitance of more than 15\(\times \).     

Design and modeling of a novel RF MEMS series switch with low actuation voltage

This paper presents the design, analysis, modeling and simulation of a novel RF MEMS series switches with low actuation voltage. A mechanical modeling is presented to describe the behavior of the series switch. The switch is designed with special mechanical structures. The novel mechanical and mathematical modeling of the switch leads to calculation of the accurate actuation voltage. The spring constant has been calculated in relation to the presence of the residual stress in the beam. The calculated spring constant for this beam is used to determine the accurate actuation voltage. The size of the switch is 60 × 110 µm². The designed RF MEMS series switch was simulated using Intellisuite MEMS tool. He calculated actuation voltage is 4.05 V and simulated one is 4.2 V for 0.6 µm beam thickness. The calculated result is also very close with simulated one. The proposed switch compared with other electrostatic switches has low actuation voltage and small size. The RF characteristics were simulated using HFSS software and the switch has good RF performance. The insertion loss of 0.067 dB, return loss of 26 dB and isolation of 16 dB were achieved at 40 GHz.     

RF-MEMS Capacitive Switches Fabricated Using Printed Circuit Processing Techniques

This paper presents radio frequency microelectromechanical systems (RF-MEMS) capacitive switches fabricated using printed circuit processing techniques. The key feature of this approach is the use of most commonly used flexible circuit film, Kapton E polyimide film, as the movable switch membrane. The physical dimensions of these switches are in the mesoscale range. For example, electrode area of a typical capacitive shunt switch on coplanar waveguide (CPW) is 2 mmtimes1 mm, respectively. A CPW shunt switch with insertion loss <0.4 dB and isolation >10 dB in the frequency range of 8 to 30 GHz is reported. K-band, Ku-band, and X-band high-isolation CPW shunt switches designed by inductive compensation of the switch down-position capacitance are also presented. Inductance compensation has been implemented by introducing inductive step-in-width junctions in the MEMS switch electrode. The K-band switch provides a maximum isolation value of 54 dB at 18 GHz. For the K-band switch, the insertion loss is less than 0.3-0.4 dB in the frequency range of 1-30 GHz and the isolation values are better than 20 dB in the frequency range of 12 to 30 GHz. The Ku-band switch provides a maximum isolation of 46 dB at 16.5 GHz. For the Ku-band switch, the insertion loss is less than 0.4-0.45 dB in the frequency range of 1-30 GHz and the isolation is greater than 20 dB in the frequency range of 12 to 22 GHz. The X-band switch provides a maximum isolation value of 32 dB at 10.6 GHz. The insertion loss is less than 0.25-0.3 dB in the frequency range of 1-18 GHz and the isolation is better than 20 dB in the frequency range of 8.5 to 13.5 GHz for the X-band switch. The measured typical pull-down voltage is in the range of 100-120 for this type of switches. These switches are uniquely suitable for monolithic integration with printed circuits and antennas on organic laminate substrates     

RF MEMS membrane switches on GaAs substrates for X-band applications

Micromechanical switches have demonstrated great potential at microwave frequencies. For low-loss applications at microwave frequencies, it is important to use high-resistivity substrates. This paper presents the design and fabrication of the shunt-capacitive MEMS switch on GaAs substrates. Analytical mechanical and impedance models of the membrane switch are given, and the results are confirmed by using the ANSYS and HFSS software, respectively. A surface micromachining process, which is compatible with the conventional millimeter-wave integrated circuits (MMICs) fabrication technology, was adopted to fabricate the RF switch on GaAs substrates. Its S-parameter was taken using a HP8510C vector network analyzer and a Cascade Probe station. The measured insertion loss of the switch and its associated transmission line is less than 0.25 dB from 1 to 25.6 GHz, and the isolation may reach -42 dB at its self-resonate frequency of 24.5 GHz. The actuation voltage is about 17 V. The switch has demonstrated lifetimes as long as 5/spl times/10/sup 6/ cycles. The wideband high performance in isolation and insertion loss offers the monolithic integration capability with GaAs MMICs.     

Broadband radio frequency MEMS series contact switch with low insertion loss

A new radio frequency (RF) micro-electro-mechanical-system (MEMS) single cantilever series contact switch is designed as a low-insertion-loss and low-power electronic component that is intended to provide integrated control of the opening and closing signals of other MEMS devices operating over a wide frequency range (DC–60 GHz). The MEMS switching element consists of an A-type top electrode that is fixed onto coplanar waveguide lines through anchor points to reduce the insertion loss in the on-state of the device. The air gap between the top electrode and the actuation electrode of the designed MEMS switch is optimized to improve the isolation characteristics of the switch. In addition, the switching voltage required is approximately 24 V. The simulation results presented here show that the insertion loss of the switch in the on-state is less than 0.71 dB, while the minimum isolation is 20.69 dB in the off-state at 60 GHz. The proposed RF MEMS switch will be useful for communication devices and test instruments used in broadband applications.

     

Thin-Film Encapsulated RF MEMS Switches

A wafer-level thin-film encapsulation process has been demonstrated to package radio-frequency (RF) microelectromechanical systems (MEMS) switches in this paper. Individual shunt capacitive switches were packaged in a ~1nL inorganic enclosure with process temperatures not exceeding 300 degC. A shell covering the switch consisted of 10 nm of sputtered alumina and 1.67 mum of sputtered silicon nitride dielectric film. The switch and dielectric shell were simultaneously wet-released through access channels in the shell. Following release, access channels were sealed with 10 nm of sputtered alumina and 2-4 mum of either plasma-enhanced chemical vapor deposited silicon dioxide or silicon nitride. Electromagnetic simulation and RF test results before and after sealing show minimal RF degradation of switch performance. Before sealing, the insertion loss and isolation at 10 GHz averaged 0.12 and 10.7 dB, respectively. After sealing, the same devices had an average insertion loss and isolation of 0.12 and 10.1 dB, respectively. Complete characterization of the package atmosphere was not completed due to challenges in assessing nanoliter-scale volumes     

A Liquid–Solid Direct Contact Low-Loss RF Micro Switch

This paper reports the design, fabrication, and testing of a liquid-metal (LM) droplet-based radio-frequency microelectromechanical systems (RF MEMS) shunt switch with dc-40 GHz performance. The switch demonstrates better than 0.3 dB insertion loss and 20 dB isolation up to 40 GHz, achieving significant improvements over previous LM-based RF MEMS switches. The improvement is attributed to use of electrowetting on dielectric (EWOD) as a new actuation mechanism, which allows design optimized for RF switching. A two-droplet design is devised to solve the biasing problem of the actuation electrode that would otherwise limit the performance of a single-droplet design. The switch design uses a microframe structure to accurately position the liquid-solid contact line while also absorbing variations in deposited LM volumes. By sliding the liquid-solid contact line electrostatically through EWOD, the switch demonstrates bounceless switching, low switch-on time (60 mus), and low power consumption (10 nJ per cycle).     

Design and simulation of a thermally actuated MEMS switch for microwave circuits

The design, modeling, and optimization of a novel, thermally actuated CMOS‐MEMS switch are presented in this article. This series capacitive MEMS switch solves the substrate loss and down‐state capacitance degradation problems commonly plaguing MEMS switches. The switch uses finger structure for capacitive coupling. The vertical bending characteristic of bimorph cantilever beams under different temperatures is utilized to turn the switch on and off. A set of electrical, mechanical, and thermal models is established, and cross‐domain electro‐thermo‐mechanical simulations are performed to optimize the design parameters of the switch. The fabrication of the switch is completely CMOS‐process compatible. The design is fabricated using the AMI 0.6 μm CMOS process and a maskless reactive‐ion etching process. The measured results show the insertion loss and isolation are 1.67 and 33 dB, respectively, at 5.4 GHz, and 0.36 and 23 dB at 10 GHz. The actuation voltage is 25 V and the power consumption is 480 mW. This switch has a vast number of applications in the RF/microwave field, such as configurable voltage control oscillators, filters, and configurable matching networks. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

A low voltage vertical comb RF MEMS switch

Design and simulations of a novel RF MEMS switch is reported as a solution to many RF wireless applications. A new comb structure for RF MEMS switch is proposed for low voltage and high frequency operations. Isolation degree and actuation voltage, both improved by the new structure. The mechanical and electromagnetic simulation results show better performance for this new switch compared to parallel plate switch. The simulation is done by the intellisuit and HFSS softwares. The Simulation results show that the actuation voltage is decreased by 13% and the linearity of the switch displacement with respect to the actuation voltage is improved by 22% compared to the parallel plate structure. The HFSS simulation results indicate an insertion loss better than 0.33 dB at 50 GHz and isolation greater than 13.4 dB at 50 GHz.     

Inductively‐loaded RF MEMS reconfigurable filters

This article presents an inductively loaded radio frequency (RF) microelectromechanical systems (MEMS) reconfigurable filter with spurious suppression implemented using packaged metal‐contact switches. Both simulation and measurement results show a two‐state, two‐pole 5% filter with a tuning range of 17% from 1.06 GHz to 1.23 GHz, an insertion loss of 1.56–2.28 dB and return loss better than 13 dB over the tuning range. The spurious passband response in both states is suppressed below ?20 dB. The unloaded Q of the filter changes from 127 to 75 as the filter is tuned from 1.06 GHz to 1.23 GHz. The design and full‐wave simulation of a two‐bit RF MEMS tunable filter with inductively loaded resonators and monolithic metal‐contact MEMS switches is also presented to prove the capability of applying the inductive‐loading technique to multibit reconfigurable filters. The simulation results for a two‐bit reconfigurable filter show 2.5 times improvement in the tuning range compared with the two‐state reconfigurable filter due to lower parasitics associated with monolithic metal‐contact MEMS switches in the filter structure. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

MEMS capacitive series switch fabricated using PCB technology

In this article, an RF MEMS capacitive series switch fabricated using printed circuit processing techniques is discussed. Design, modeling, fabrication, and characterization of the CPW series switch are presented. An example CPW series capacitive switch with insertion loss less than 0.5 dB in the frequency range of 13–18 GHz and isolation better than 10 dB up to 18 GHz is discussed. The switch provides a minimum insertion loss of about 0.1 dB at the self‐resonance frequency of 16 GHz and a maximum isolation of about 42 dB at 1 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

串联电容式RF MEMS开关设计与制造研究

介绍了一种串联电容式RF MEMS开关的设计与制造。所设计的串联电容式RF MEMS开关利用薄膜淀积中产生的内应力使MEMS桥膜向上发生翘曲,从而提高所设计的开关的隔离度,克服了串联电容式RF MEMS开关通常只有在1GHz以下才能获得较高隔离度的缺点。其工艺与并联电容式RF MEMS开关完全相同,解决了并联电容式RF MEMS开关不能应用于低频段(<10GHz)的问题。其插入损耗为-0.88dB@3GHz,在6GHz以上,插入损耗为-0.5dB;隔离度为-33.5dB@900MHz、-24dB@3GH和-20dB@5GHz,适合于3~5GHz频段的应用。     

Performance analysis of RF MEMS capacitive switch with non uniform meandering technique

This Paper reports on investigation of High C_on C_off ratio Capacitive Shunt RF MEMS Switch and detailed comparison between uniform three meander beam with non-uniform single meander beam RF MEMS switch. RF MEMS Switches are designed for operation in the range 5–40 GHz. Pull in analysis is performed with gold as a beam material. Simulation reveals that use of high K dielectric material can drastically improve the capacitance ratio of switch. For the same geometry, pull in voltage is 2.45 V for HfO₂, 2.7 V for Si₃N₄ and Capacitive Ratio of the switch with Si₃N₄ is 83.75 and Capacitive Ratio with HfO₂ is 223 at 2g₀ (air gap) and 0.8 μm thickness of beam. The Radio Frequency performance of RF MEMS switch is obtained by scattering parameters (insertion loss, Return loss and isolation) which are mainly dominated by down to up capacitance ratio and MEMS bridge geometries. RF analysis shows that insertion loss as low as ?0.4 dB at 20 GHz and isolation as high as 80 dB at 20 GHz can be achieved. Investigation of three uniform meander Design and non-uniform single meander design reveals that use of non-uniform design reduces the design complexity and saves substrate area still maintaining almost same device performance. S-parameter analysis is carried out to compare device performance for both structures. DC analysis of the proposed switch is carried out using Coventorware and RF analysis is performed in MATLAB.     

Multiport RF MEMS switch for satellite payload applications

Microsystem Technologies - Design, fabrication and characterization of a novel RF switch is proposed in this paper. The multiport RF MEMS switch provides a single input multiple output novel...     

A W‐band RF‐MEMS switched LNA in a 70 nm mHEMT process

This work presents a monolithic integrated reconfigurable active circuit consisting of a W‐band RF micro‐electro‐mechanical‐systems (MEMS) Dicke switch network and a wideband low‐noise amplifier (LNA) realized in a 70 nm gallium arsenide (GaAs) metamorphic high electron mobility transistor process technology. The RF‐MEMS LNA has a measured gain of 10.2–15.6 dB and 1.3–8.2 dB at 79–96 GHz when the Dicke switch is switched ON and OFF, respectively. Compared with the three‐stage LNA used in this design the measured in‐band noise figure (NF) of MEMS switched LNA is minimum 1.6 dB higher. To the authors’ knowledge, the experimental results represent a first time demonstration of a W‐band MEMS switched LNA monolithic microwave integrated circuit (MMIC) in a GaAs foundry process with a minimum NF of 5 dB. The proposed novel integration of such MEMS switched MMICs can enable more cost‐effective ways to realize high‐performance single‐chip mm‐wave reconfigurable radiometer front‐ends for space and security applications, for example. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:639–646, 2015.     

Design of novel compact anti-stiction and low insertion loss RF MEMS switch

A novel torsional RF MEMS capacitive switch design on silicon substrate is presented. The optimized switch topology such as reduction in up-state capacitance results in insertion loss better than ?0.1 dB till 20 GHz. Off to on state capacitance ratio is also improved by 18 fold and isolation is better than ?43 dB at 9.5 GHz. The achieved on state return loss is ?38 dB as compared to ?21 dB at 9.5 GHz. An optimized reduction in contact area and use of floating metal layer increases the switching speed from 56 to 46 μsec. It also increases the switch reliability by alleviating the stiction.     

Design and analysis of a RF MEMS shunt switch using U-shaped meanders for low actuation voltage

This paper presents the design and simulation of RF MEMS switch using uniform U-Shaped meanders. High isolation and low insertion loss are the main performance parameters enhanced by considering the inductive sections on the design and developing high capacitance using HfO₂ as a dielectric medium. The inductive sections in the design help maintain the device at resonance. The proposed uniform U-shaped meanders lower the spring constant and reduce the Pull-in-voltage of the switch. The performance characteristics are observed by simulating the proposed switch in the electromechanics environment using the COMSOL FEM tool. The switch exhibits a low Pull-in-voltage of 5.2 V with a very low switching time of 23.1 µs. Total capacitance of 42.19 fF is formed during upstate which provides a low insertion loss of less than 0.1 dB. Capacitance of 19.11 pF during downstate provides high isolation of − 42.11 dB.

     

A low-voltage lateral MEMS switch with high RF performance

MEMS switches are one of the most promising future micromachined products that have attracted numerous research efforts in recent years. The majority of MEMS switches reported to date employ electrostatic actuation, which requires large actuation voltages. Few are lateral relays and those often require nonstandard post process, and none of them is intended for high-frequency applications. We have developed an electrothermally actuated lateral-contact microrelay for RF applications. It is designed and fabricated on both low-resistivity and high-resistivity silicon substrate using surface micromachining techniques. The microrelay utilizing the parallel six-beam actuator requires an actuation voltage of 2.5-3.5 V. Time response is measured to be 300 /spl mu/s and maximum operating frequency is 2.1 kHz. The RF signal line has a current handling capability of approximately 50 mA. The microrelay's power consumption is in the range of 60-100 mW. The lateral contact mechanism of the microrelay provides a high RF performance. The microrelay has an off-state isolation of -20 dB at 40 GHz and an insertion loss of -0.1 dB up to 50 GHz. The simplicity of this 4-mask fabrication process enables the possibility of integrating the microrelay with other passive RF MEMS components.     

Design and performance analysis of double cantilever type capacitive shunt RF MEMS switch

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.