Design and investigation of a low insertion loss,broadband, enhanced self and hold down power RF-MEMS switch

This paper presents a low insertion loss capacitive shunt RF-MEMS switch. In the presented design, float metal concept is utilized to reduce the capacitance in up-state of the device. Float metal switch shows an insertion loss <0.11 dB, a return loss below 26.27 dB up to 25 GHz as compared to 0.81 dB insertion, 8.67 dB return loss for the conventional switch without float metal. OFF state response is same for the both devices. Further pull-in voltage of 12.75 V and switching time of 69.62 µs have been observed in case of the conventional switch whereas device with float metal have 11.75 V and 56.41 µs. Improvement of around 2.5 times in bandwidth and 4 times in input power has been observed without self actuation, hold down problem. The designed switch can be useful at device and sub-system level for multi-band applications.     

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\(\times \).     

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.     

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     

一种超宽带MEMS开关的研制

MEMS射频器件,特别是超宽带器件,对其中的射频器件提出了宽带指标的要求。以此为背景,在理论分析的基础上设计了一种应用于12.5 GHz~50 GHz频带的超宽带双膜桥式MEMS开关,该开关具备低损耗、高隔离度等特点,文中给出了开关的制备工艺,并进行流水完成了芯片制备。经测试,该开关在设计频段内,回波损耗优于20 dB,插入损耗典型值0.3 dB@12.5~35 GHz,优于0.5 dB@45 GHz,隔离度全频段优于20 dB,驱动电压在45 V~55 V之间。     

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.

     

10-26GHz CMOS六位数控衰减器设计与实现

为了使衰减器更好的适应相控阵系统对高集成度波束赋形电路的应用需求。基于55nm CMOS工艺,设计了一款具有低插入损耗、低附加相移特性的六位数控衰减器,该数控衰减器采用桥T和π型衰减结构级联而成,在10-26 GHz频率范围内实现步进为0.5dB、动态范围为0-31.5 dB的信号幅度衰减。为减小插入损耗,NMOS开关采用悬浮栅和悬浮衬底连接方式,同时采用了电容补偿网络和电感补偿以有效降低附加相移。仿真结果表明,在10-26GHz的频带范围内,该数控衰减器的插入损耗小于-7dB,输入/输出回波小于-10dB,附加相移小于±3°,所有衰减态的衰减误差均方根小于0.8dB,芯片的核心电路面积为0.36 mm×0.16 mm。     

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.     

Design,optimization and simulation of a low-voltage shunt capacitive RF-MEMS switch

This paper presents the design, optimization and simulation of a radio frequency (RF) micro-electromechanical system (MEMS) switch. The capacitive RF-MEMS switch is electrostatically actuated. The structure contains a coplanar waveguide, a big suspended membrane, four folded beams to support the membrane and four straight beams to provide the bias voltage. The switch is designed in standard 0.35 µm complementary metal oxide semiconductor process and has a very low pull-in voltage of 3.04 V. Taguchi method and weighted principal component analysis is employed to optimize the geometric parameters of the beams, in order to obtain a low spring constant, low pull-in voltage, and a robust design. The optimized parameters were obtained as w = 2.5 µm, L1 = 30 µm, L2 = 30 µm and L3 = 65 µm. The mechanical and electrical behaviours of the RF-MEMS switch were simulated by the finite element modeling in software of COMSOL Multiphysics 4.3^® and IntelliSuite v8.7^®. RF performance of the switch was obtained by simulation results, which are insertion loss of ?5.65 dB and isolation of ?24.38 dB at 40 GHz.     

Miniaturized frequency‐agile bandpass filter integrated single‐pole double‐throw switch

This article presents a miniaturized frequency‐agile bandpass filter (BPF) integrated single pole double throw (SPDT) switch using common LC resonator. The BPF‐integrated on‐sate channel is constituted by the capacitively coupled LC resonators with loaded varactor diodes and reverse‐biased p‐i‐n diodes. The off‐state channel with high suppression is built when the p‐i‐n diodes loaded LC resonators is forward‐biased. As an example, a frequency‐agile BPF‐integrated SPDT switch with constant 3‐dB fractional bandwidth of 18.4% is designed. Its fabricated circuit area including bias circuit but excluding feeding lines is 0.105 λ_g × 0.079 λ_g. Measured results show that its 3 dB operating frequency bandwidth covers from 0.499 to 1.077 GHz with in‐band insertion loss varying from 4.15 to 3.15 dB. Off‐state suppression better than 37.8 dB, port‐to‐port isolation better than 51.1 dB, and good return loss can be also observed.     

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.     

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 lateral RF MEMS capacitive switch utilizing parylene as dielectric

A novel lateral RF MEMS capacitive switch was reported in this paper. This switch employed parylene as the dielectric material, taking advantages of its low temperature deposition and conformal coating. The low resistivity single crystalline silicon served as the material of the mechanical structures. The switch was fabricated by bulk micromachining processes with only two lithographic masks and a shadow mask. The dynamical response, parylene insulation performance, and RF performances of the fabricated switch were characterized, respectively. The switching time from the open state to the close state was 105 μs at a loaded voltage of 78 V, while 15.6 μs from the close state to the open state. The isolation was better than 15 dB from 20 to 40 GHz, and the maximal isolation was 23.5 dB at 25 GHz; while the insertion loss was below 1.4 dB at 25 GHz, when bonding wires connected the ground lines. These results verify that the parylene is a good candidate material to act as sidewall dielectric to realize the lateral capacitive switch.     

Ladder‐lattice bulk acoustic wave filters: Concepts,design, and implementation

This article presents a study of ladder‐lattice bulk acoustic wave (BAW) filters. First, a review of BAW technology and filters topologies is addressed. Next, a mixed ladder‐lattice BAW filter for application on W‐CDMA reception front‐ends (2.11–2.17 GHz) is presented. An improved solidly mounted resonators (SMR) technology was used for the filter implementation. The filter synthesis methodology is briefly described. Layout guidelines are discussed enabling an optimized filter design. The filter on‐wafer measurement results are as follows: ?3.55 dB of insertion loss, ?8.7 dB of return loss, an isolation higher than ?47 dB at the transmission band (1.92–1.98 GHz) and an improved selectivity (?30 dB at 2.14 GHz ± 60 MHz). Therefore, we can observe that the mixed topology combines the advantages of ladder and lattice networks, having very steep responses and an improved isolation at undesired bands. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Compact reconfigurable rat‐race coupler with tunable frequency and tunable power dividing ratio

A compact reconfigurable rat‐race coupler with tunable frequency and tunable power dividing ratio is proposed for the first time. Varactors and two single control voltages are used to obtain both the tunable frequency and the tunable power dividing ratio in this article. The structure of the rat‐race coupler involves 50 Ω parallel‐strip lines only and a phase inverter is used for size reduction. Theoretical equations for the relationship among S‐parameters and the capacitance of varactors are derived. The graphic method is used to choose capacitance for the desired operation frequency and the desired power dividing ratio. For demonstration, a prototype is designed and fabricated. The measured results show that the rat‐race coupler's frequency and the power dividing ratio can be effectively tuned in 0.69 GHz ～ 0.81 GHz and 3 dB ～ 14 dB, respectively with isolation better than 20 dB, phase difference less than 7°and return loss better than 20 dB. The theoretical simulation, electromagnetic simulation, and measured results show good agreement in this design.     

Analysis of a novel RF MEMS switch using different meander techniques

In this paper, two types of RF MEMS switches namely step structure and Normal beam structure are designed and analyzed using different meander techniques. Three techniques namely plus, zigzag and three-square meander were used to lower the pull-in voltage. The actuating beam is designed with the rectangular perforations affects the performance of a switch by lowering the pull-in voltage, switching speed and results in better isolation. In this paper a comparative analysis is done for all three meander techniques with and without perforations on the beam. Total six structures have been designed with the combination three meanders and two different beam structures. The proposed stepdown structure exhibits high performance characteristics with a very low pull-in voltage of 1.2 V having an airgap of 0.8 µm between the actuation electrodes. The gold is used as beam material and HfO₂ as the dielectric material such that the upstate and downstate capacitance is seen as 1.02 fF and 49 fF. The FEM analysis is done to calculate the spring constant and thereby the pull-in voltage and behavior of the switch is studied with various parameters. The switch with a step structure and three-square meander configuration has shown best performance of all by requiring a pull-in voltage of 1.2 V and lower switching time of 0.2 µs. The proposed switch also exhibits good RF performance characteristics with an insertion loss below − 0.07 dB and return loss below − 60 dB over the frequency range of 1–40 GHz. At 28 GHz a high isolation of − 68 dB is exhibited.

     

A CMOS low noise amplifier based on common source technique for ISM band application

In this paper a 2.45 GHz narrowband low noise amplifier (LNA) for wireless communication system is enunciated. The proposed CMOS Low Noise amplifier has been verified through cadence spectre RF simulation in standard UMC 90 nm CMOS process. The proposed LNA is designed by cascoding of two transistors; that is the common source transistor drives a common gate transistor. To achieve better power gain along with low noise figure, cascoding of two transistor and source degeneration technique is used and for low power consumption, the MOS transistors are biased in subthreshold region. At 2.45 GHz frequency, it exhibits power gain 31.53 dB. The S11, S22 and S12 of the circuit is ?9.14, ?9.22 and ?38.03 dB respectively. The 1 dB compression point of the circuit is ?16.89 dBm and IIP3 is ?5.70 dBm. The noise figure is 2.34 dB, input/output match of ?9.14 dB/?9.22 dB and power consumption 8.5 mW at 1.2 V.     

新型小型化超宽带功率分配器的设计

利用四分之三波长折叠微带线与四分之一波长微带线级联,并在输入端口引入四分之一波长短路线,设计出一种新型的超宽带功率分配器.采用奇偶模的方法进行理论分析,导出设计参数方程,并通过HFSS进行仿真优化.仿真和测量结果表明,输入回波损耗从3 GHz～10.9 GHz均大于10 dB.插入损耗从2.6 GHz～9.5 GHz均...     

A 60‐GHz single‐pole‐single‐throw switch in 65‐nm bulk CMOS

A single‐pole‐single‐throw (SPST) switch in a π‐network topology is designed in a 1.2‐V 65‐nm bulk CMOS RF process for millimeter‐wave applications in the 60‐GHz band from 57 to 66 GHz. The SPST switch with an active chip area of only 96 μm × 140 μm achieves the measured 11‐dB return loss, 1.6‐dB insertion loss, and 27.9‐dB isolation at 60 GHz. The SPST switch also shows the simulated power‐handling capability of 11.4 dBm and switching speed of 1 ns at 60 GHz. These results clearly demonstrate that the SPST switch in CMOS rivals the performance of SPST switches in GaAs and therefore has potential to be used in highly‐integrated 60‐GHz CMOS radios. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

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).