DCDC—20GHz射频MEMS开关

描述了 DC— 2 0 GHz射频 MEMS开关的设计和制造工艺 .开关为一薄金属膜桥组成的桥式结构 ,形成一个单刀单掷 (SPST)并联设置的金属 -绝缘体 -金属接触 .开关通过上下电极之间的静电力进行控制 ,其插入损耗及隔离性能取决于开态和关态的电容 .测试结果如下 :射频 MEMS开关驱动电压约为 2 0 V,在“开”态下 DC— 2 0 GHz带宽的插入损耗小于 0 .6 9d B;在“关”态下在 14— 18GHz时隔离大于 13d B,在 18— 2 0 GHz时隔离大于 16 d B.本器件为国内首只研制成功的宽带射频 MEMS开关     

High-isolation CPW MEMS shunt switches. 1. Modeling

This paper, the first of two parts, presents an electromagnetic model for membrane microelectromechanical systems (MEMS) shunt switches for microwave/millimeter-wave applications. The up-state capacitance can be accurately modeled using three-dimensional static solvers, and full-wave solvers are used to predict the current distribution and inductance of the switch. The loss in the up-state position is equivalent to the coplanar waveguide line loss and is 0.01-0.02 dB at 10-30 GHz for a 2-μm-thick Au MEMS shunt switch. It is seen that the capacitance, inductance, and series resistance can be accurately extracted from DC-40 GHz S-parameter measurements. It is also shown that dramatic increase in the down-state isolation (20⁺ dB) can be achieved with the choice of the correct LC series resonant frequency of the switch. In part 2 of this paper, the equivalent capacitor-inductor-resistor model is used in the design of tuned high isolation switches at 10 and 30 GHz     

高隔离度X波段RF MEMS电容式并联开关

研究了一种新型的、应用于X波段的高隔离度RF MEMS电容式并联开关结构。相比于普通的并联结构,该开关通过共面波导(CPW)传输线与地平面之间的衬底刻槽结构将隔离度提高了7dB,关态时在13.5GHz谐振频率处的隔离度为-54.6dB,执行电压为26V。弹簧梁结构开关的执行电压下降为14V,在11GHz处其隔离度为-42.8dB。通过两个并联开关级联与开关间的高阻传输线构成的π型调谐开关电路,在11.5GHz处的隔离度为-81.6dB。     

RF MEMS开关的设计分析

针对具有低损耗、高隔离度性能的微机电系统(Micro-Electro-Mechanical System,MEMS)开关,介绍了串联DC式和并联电容式的开关结构模型,并对并联电容式MEMS开关的工作原理、等效电路模型和制造工艺流程进行了描述,利用其模型研究了开关的微波传输性能,设计了一款电容耦合式开关并进行了仿真。由仿真结果可得,开关"开态"时的插入损耗在40 GHz以内优于-0.3 dB;开关"关态"时的隔离度在20～40 GHz相对较宽的频带内优于-20 dB。     

高隔离度宽频带MEMS双膜桥开关

利用一种新型双边加直流驱动电极的电容耦合式MEMS并联膜开关与直接接触式并联膜开关进行级联,形成MEMS双膜开关.通过对其尺寸和结构的优化,降低开关阈值电压,Coventor软件模拟表明,开关的阈值电压小于20V;通过对其匹配设计改善开关的高频性能,HFSS软件模拟的结果表明,在DC～20GHz整个频带内,开关的插入损耗优于-0.1dB,反射损耗低于-30dB,隔离度低于-20dB,在 谐振点处隔离度能达到-40dB.     

High-isolation W-band MEMS switches

This paper presents the design, fabrication and measurement of single, T-match and π-match W-band high-isolation MEMS shunt switches on silicon substrates. The single and T-match design result in -20 dB isolation over the 80-110 GHz range with an insertion loss of 0.25±0.1 dB. The π-match design results in a reflection coefficient lower than -20 dB up to 100 GHz, and an isolation of -30 to -40 dB from 75 to 110 GHz (limited by leakage through the substrate). The associated insertion loss Is 0.4±0.1 dB at 90 GHz. To our knowledge, this is the first demonstration of high-performance MEMS switches at W-band frequencies     

Inline capacitive and DC-contact MEMS shunt switches

This paper presents inline capacitive MEMS shunt switches suitable for X/K-band and Ka/V-band applications. The inline switch allows for a low- or high-inductance connection to the ground plane without changing the mechanical characteristics of the MEMS bridge. Excellent isolation and loss are achieved with this design, and the performance is very similar to the standard capacitive MEMS shunt switch. Also, a new metal-to-metal contact MEMS shunt switch is presented. A novel pull-down electrode is used which applies the electrostatic force at the same location as the metal-to-metal contact area. A contact resistance of 0.15-0.35 Ω is repeatable, and results in an isolation of -40 dB at 0.1-3 GHz. The measured isolation is still better than -20 dB at 40 GHz. The application areas are in high-isolation/low-loss switches for telecommunication and radar systems     

A novel loss compensation technique analysis and design for 60 GHz CMOS SPDT switch

A novel loss compensation technique for a series-shunt single-pole double-throw (SPDT) switch is presented operating in the 60 GHz. The feed-forward compensation network which is composed of an NMOS, a couple capacitance and a shunt inductance can reduce the impact of the feed forward capacitance to reduce the insertion loss and improve the isolation of the SPDT switch. The measured insertion loss and isolation characteristics of the switch somewhat deviating from the 60 GHz are analyzed revealing that the inaccuracy of the MOS model can greatly degrade the performance of the switch. The switch is implemented in TSMC 90-nm CMOS process and exhibits an isolation of above 27 dB at transmitter mode, and the insertion loss of 1.8-3 dB at 30-65 GHz by layout simulation. The measured insertion loss is 2.45 dB at 52 GHz and keeps<4 dB at 30-64 GHz. The measured isolation is better than 25 dB at 30-64 GHz and the measured return loss is better than 10 dB at 30-65 GHz. A measured input 1 dB gain compression point of the switch is 13 dBm at 52 GHz and 15 dBm at 60 GHz. The simulated switching speed with rise time and fall time are 720 and 520 ps, respectively. The active chip size of the proposed switch is 0.5×0.95 mm².     

$Ka$-Band Low-Loss and High-Isolation Switch Design in 0.13-$mu{hbox {m}}$ CMOS

This paper presents designs and measurements of Ka-band single-pole single-throw (SPST) and single-pole double-throw (SPDT) 0.13-CMOS switches. Designs based on series and shunt switches on low and high substrate resistance networks are presented. It is found that the shunt switch and the series switch with a high substrate resistance network have a lower insertion loss than a standard designs. The shunt SPST switch shows an insertion loss of 1.0 dB and an isolation of 26 dB at >35 GHz. The series SPDT switch with a high substrate resistance network shows excellent performance with 2.2-dB insertion loss and isolation at 35 GHz, and this is achieved using two parallel resonant networks. The series-shunt SPDT switch using deep n-well nMOS transistors for a high substrate resistance network results in an insertion loss and isolation of 2.6 and 27 dB, respectively, at 35 GHz. For series switches, the input 1-dB compression point (1P₁) can be significantly increased to with the use of a high substrate resistance design. In contrast, of shunt switches is limited by the self-biasing effect to 12 dBm independent of the substrate resistance network. The paper shows that, with good design, several 0.13- CMOS designs can be used for state-of-the-art switches at 26-40 GHz.     

Fabrication and Numerical Simulation of a Micromachined Contact Cantilever RF-MEMS Switch

研究了一种直接接触悬臂梁式RF-MEMS开关,悬臂梁采用Al金属材料.开关通过静电控制,且与信号通道分离.为了优化材料结构和获得好的性能,进行了有限元ANSYS模拟.采用表面微加工工艺来制作开关,获得满意结果.器件的驱动电压为12V,与ANSYS模拟结果11V基本相符;器件的隔离度,在0.05～10GHz的范围内,实验测试与HFSS模拟的结果基本一致,都优于-20dB;器件的插入损耗,HFSS模拟小于-0.2dB,而实验测试小于-0.9dB,偏高是由于悬臂梁表面不平,导致接触电阻增大,在测试中引入接触阻抗所致.     

接触式悬臂梁RF-MEMS开关的研制与数值模拟分析

研究了一种直接接触悬臂梁式RF-MEMS开关,悬臂梁采用Al金属材料.开关通过静电控制,且与信号通道分离.为了优化材料结构和获得好的性能,进行了有限元ANSYS模拟.采用表面微加工工艺来制作开关,获得满意结果.器件的驱动电压为12V,与ANSYS模拟结果11V基本相符;器件的隔离度,在0.05～10GHz的范围内,实验测试与HFSS模拟的结果基本一致,都优于-20dB;器件的插入损耗,HFSS模拟小于-0.2dB,而实验测试小于-0.9dB,偏高是由于悬臂梁表面不平,导致接触电阻增大,在测试中引入接触阻抗所致.     

基于微机电系统开关的四位移相器设计

为了解决相控阵雷达小型化和低损耗的问题,设计了一个工作频率为2.2 GHz的射频微机电系统(MEMS)四位开关线型移相器。首先分析了直接接触式MEMS串联开关的插入损耗和隔离度,并得到仿真结果。在此基础上设计了基于该开关的移相范围为0~180o的四位移相器电路,相移量为12o每步。采用HFSS软件对其进行仿真,得到移相精确度、插入损耗和隔离度等关键结果,移相器工作在2.2 GHz时,隔离度大于20 dB,插入损耗小于1 dB。该设计与传统移相器相比体积更小,且具有更小的插入损耗和更大的隔离度。     

DC－40GHzMMIC开关

ＤＣ－４０ＧＨｚＭＭＩＣ开关叶禹康，俞土法，伍祥冰（南京电子器件研究所，２１００１６）提要＊用微波单片集成电路（ＭＭＩＣ）技术设计制作了高隔离度、超快速ＤＣ－４０ＧＨｚＭＭＩＣ开关（ＳＰＳＴ）。开关采用串联、并联单元ＭＥＳＦＥＴ兼用的电路结构。芯片尺...     

DC－40GHzMMIC开关

ＤＣ－４０ＧＨｚＭＭＩＣ开关叶禹康，俞土法，伍祥冰（南京电子器件研究所，２１００１６）提要＊用微波单片集成电路（ＭＭＩＣ）技术设计制作了高隔离度、超快速ＤＣ－４０ＧＨｚＭＭＩＣ开关（ＳＰＳＴ）。开关采用串联、并联单元ＭＥＳＦＥＴ兼用的电路结构。芯片尺...     

RF MEMS开关工艺技术研究

RFMEMS开关是用MEMS技术形成的新型电路元件,与传统的半导体开关器件相比具有插入损耗低、隔离度大等优点,将对现有雷达和通信中RF结构产生重大影响。文章介绍了RFMEMS开关的基本工艺流程设计,工艺制作技术的研究。实验解决了种子层技术、聚酰亚胺牺牲层技术、微电镀技术的工艺难题,制作出了RFMEMS开关样品,基本掌握了RFMEMS器件的制作工艺技术。RFMEMS开关样品测试的技术指标为:膜桥高度2μm～3μm、驱动电压<30V、频率范围0～40GHz、插入损耗≤1dB、隔离度≥20dB,样品参数性能达到了设计要求。     

High power DPDT antenna switch MMIC for digital cellular systems

In this paper, we propose two new types of dual-pole double-throw (DPDT) switch GaAs JFET monolithic microwave integrated circuits (MMICs) for digital cellular handsets. These ICs have the excellent characteristics of low insertion loss and high power handling capability, even with a low control voltage by stacking three JFETs with shallow V_p and using a novel bias circuit using p-n junction diodes. One DPDT switch IC has two shunt FET blocks and can achieve high isolation without external parts. An insertion loss less than 0.6 dB and isolation over 25 dB up to 2 GHz were achieved. P_1dB was about 35 dBm even with a control voltage of 0/3 V. Another DPDT switch IC utilizes parallel resonance of external inductors and parasitic capacitance between the drain and the source of the OFF-state FETs. By attaching 15 nH inductors, for example, the IC exhibited an insertion loss as low as 0.4 dB, an isolation of better than 40 dB at 1.5 GHz, a bandwidth of about 400 MHz for 20 dB isolation, and P_1dB of about 34 dBm with the 0/3 V control     

A low-loss single-pole six-throw switch based on compact RF MEMS switches

A low-loss single-pole six-throw (SP6T) switch using very compact metal-contact RF microelectromechanical system (MEMS) series switches is presented. The metal-contact MEMS switch has an extremely compact active area of 0.4 mm /spl times/ 0.3 mm, thus permitting the formation of an SP6T MEMS switch into the RF switch with a total area of 1 mm/sup 2/. The MEMS switch shows an effective spring constant of 746 N/m and an actuation time of 8.0 /spl mu/s. It has an isolation loss from -64.4 to -30.6dB and an insertion loss of 0.08-0.19 dB at 0.5-20 GHz. Furthermore, in order to evaluate RF performances of the SP6T MEMS switch, as well as those of the single-pole single-throw RF MEMS series switch, we have performed small-signal modeling based on a parameter-extraction method. Accurate agreement between the measured and modeled RF performances demonstrates the validity of the small-signal model. The SP6T switch performed well with an isolation loss from -62.4 to -39.1dB and an insertion loss of 0.19-0.70 dB from dc to 6 GHz between the input port and each output port.     

一种L～E波段的混合型射频MEMS单刀双掷开关设计

针对传统RF MEMS单刀双掷(SPDT)开关应用存在频段低、插入损耗高、隔离度低等问题,设计了一种混合型SPDT开关,通过在一条通路上设置接触式开关和电容式开关,实现了在L～E频段下的低插入损耗和高隔离度。通过设计蛇形上电极结构,降低了上电极的弹性系数,进而降低开关上电极下拉所需的驱动电压。采用HFSS仿真软件对混合型SPDT开关的射频性能参数进行了优化,并利用COMSOL对开关的蛇形上电极进行应力-位移分析。仿真结果表明,在DC～90 GHz的频段下,SPDT开关的插入损耗小于1.5 dB@90 GHz,隔离度大于52 dB@67 GHz、29 dB@90 GHz。此开关适用于无线通信系统、雷达系统和仪器测量系统等对工作频段要求高的领域内。     

GaAs PIN二极管大功率毫米波单刀双掷开关单片

采用76.2mm(3英寸)GaAs PIN二极管工艺设计和制作了大功率毫米波单刀双掷开关单片。采用并联结构的单刀双掷开关以获得较高的功率特性。在片测试表明,在30～36GHz工作频段,开关导通支路插损1.0dB,驻波优于1.5,开关关断端口隔离度大于34dB。开关在导通态下输入功率0.5dB压缩点P-0.5 dB大于5W。     

一种DC～5GHz串联微波开关的温度特性和功率处理能力的测试与分析

描述了一种串联微波MEMS开关的设计、制造过程,它制作在玻璃衬底上,采用金铂触点,在DC～5GHz,插损小0.6dB,隔离度大于30dB,开关时间小于30μs.对这种微波开关的温度特性和功率处理能力进行了测试,在DC～4GHz,85℃下的插损增加了0.2dB,-55℃下的插损增加了0.4dB,而隔离度基本保持不变.在开关中流过的连续波功率从10dBm上升到35.1dBm,开关的插损下降了0.1～0.6dB,并且在35.1dBm(3.24W)下开关还能工作.和所报道的并联开关最大处理功率(420mW)相比,该结果说明串联开关具有较大的功率处理能力.