一种Ka频段MEMS开关的研制

设计了一种应用于Ka频段的并联电容式MEMS开关,该开关利用表面牺牲层工艺制备,具有低损耗、高隔离度等特点。经测试,开关在Ka频段内,回波损耗优于30dB,插入损耗典型值-0.13dB@27GHz,优于-0.28dB@40GHz,隔离度全频段优于22dB,驱动电压在50V~70V范围。     

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.     

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。     

低电压电容式RF MEMS开关设计研究

本文设计了一种低电压电容式RFMEMS开关,开关采用了两端固支梁结构,在梁与CPW共面波导地线的四个固定支撑位置使用了折叠结构,该结构可以减低下拉电压;通过在MEMS开关梁上开孔（直径9μm圆孔）来减小残余应力和杨氏模量和选择合适的开关梁厚度,显著降低了MEMS开关梁的弹性系数和下拉电压。以上措施显著降低了电容式RFMEMS开关的下拉电压,在ANSYS仿真下拉电压约为6V,驱动电压约为8.4V,该MEMS开关依旧保持了较好的S参数,开关插入损耗大于-0.35dB(8-40GHz),回波损耗小于-22dB(8-40GHz),隔离度（down态S21）大于25dB(8-40GHz)。     

毫米波串联接触式RF MEMS开关的设计与制造

设计了一种应用于毫米波波段的串联接触式RF MEMS开关。为了在毫米波波段获得较高的隔离度,通过使用短截线结构,以降低输入输出端口的耦合电容。为了获得可靠的金属接触,设计了一种改进型的"蟹形"桥结构。测试结果显示,在30GHz,插入损耗为-0.3dB,隔离度为-20dB。在DC～40GHz的频率范围内,插入损耗优于-0.5dB,隔离度优于-20dB。所设计的串联接触式RF MEMS开关,可应用于20～40GHz的频率范围内。     

DC-20GHz射频MEMS开关

描述了DC-20GHz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20V,在"开”态下DC-20GHz带宽的插入损耗小于0.69dB;在"关”态下在14-18GHz时隔离大于13dB,在18-20GHz时隔离大于16dB.本器件为国内首只研制成功的宽带射频MEMS开关.     

一种双波段MEMS低噪声放大器设计

本文利用一种MEMS电容式开关并联实现双波段2．1GHz／4．6GHz微机械低噪声放大器。根据MEMS电容开关的电容特性,实现LNA电路匹配阻抗的变化、在不同的波段实现谐振匹配,从而实现双波段分别放大的功能。首先提出一种电容式开关的设计,理论、仿真分析了开关的特性,开关在2．21GHz和4．8GHz具有良好的插入损耗和隔离度、插损为2．2dB左右,隔离度达到30dB以上。其次将开关引入于基于Casoode放大管的LNA电路中、和CMOS电路具有很好的兼容性,设计了LNA的电路模型和仿真分析、分析结果表明,在频率为2．21GHz时、增益达到11．4dB,4．8GHz时、增益达12．5dB,二波段隔离度在30dB以上、噪声在4．1dB左右,该研究方法和设计克服了普通双波段LNA需要两路单独电路的缺点,该器件可应用在Wimax,WiFi等3．5G、4G无移动通信网络中。     

高隔离度宽频段组合式RF-MEMS开关的设计

接触式与电容耦合式两类RF MEMS开关各自在一定的频段内,都具有较高的隔离度,但仍然很难满足微波控制系统中对高隔离度的要求.为了获得全波段高隔离度RF MEMS开关,单元开关很难达到要求,在此目标要求下,提出了组合式RF MEMS开关的设计,分别利用HFSS软件对各单元进行结构参数优化,再将两者集成在一起,得到的组合式RF MEMS开关,这种组合式开关在0～20 GHz时隔离度都高于-60 dB,在(≤5 GHz),隔离度高于-70 dB,这是一般单元开关及其他半导体固态开关所无法企及的,而且,在DC～20 GHz范围内,开关的插入损耗小于-0.20 dB,而且并没因隔离度的提高,牺牲了插入损耗.     

Design and Fabrication of Millimeter-wave DC-contact Series MEMS Switch

设计了一种应用于毫米波波段的串联接触式RF MEMS开关.为了在毫米波波段获得较高的隔离度,通过使用短截线结构,以降低输入输出端口的耦合电容.为了获得可靠的金属接触,设计了一种改进型的“蟹形”桥结构.测试结果显示,在30 GHz,插入损耗为-0.3dB,隔离度为-20 dB.在DC～40 GHz的频率范围内,插入损耗优于-0.5 dB,隔离度优于-20 dB.所设计的串联接触式RF MEMS开关,可应用于20～40 GHz的频率范围内.     

应用于可重构天线的RF MEMS开关设计

针对应用于可重构天线的RF MEMS开关进行研究,并通过HFSS软件对其进行仿真分析,开关处于关闭状态(down)时,并工作在5GHz时,开关插入损耗S21仅为-0.01dB,回波损耗在-30dB附近。开关处于闭合状态(up),在1GHz^10GHz频段,隔离度S21均小于-40dB。     

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     

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。     

Fabrication, assembly, and testing of RF MEMS capacitive switches using flexible printed circuit technology

A novel approach for cost effective fabrication, assembly, and packaging of radio-frequency microelectromechanical systems (RF MEMS) capacitive switches using flexible circuit processing techniques is reported. 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 and gap height of a capacitive shunt switch on coplanar waveguide are 2 /spl times/ 1 mm/sup 2/ and 43 /spl mu/m, respectively. Pull-down voltage is in the range of 90-100 V. In the ON state (up-position), the insertion loss is less than 0.3-0.4 dB up to 30 GHz. In OFF state (down-position), the isolation value is about 15 dB at 12 GHz and increases to 36 dB at 30 GHz. These switches are uniquely suitable for batch integration with printed circuits and antennas on laminate substrates.     

High-isolation CPW MEMS shunt switches. 2. Design

For pt.1 see ibid., vol.48, no.6, p.1045-1052 (2000). In this paper, the second of two parts, the equivalent RLC model of the shunt switch is used in the design of tuned two- and four-bridge “cross” switches from 10 to 40 GHz. The cross switch attained an insertion loss of less than 0.3-0.6 dB, a return loss below -20 dB from 22 to 38 GHz in the up state, and a down-state isolation of 45-50 dB with only 1.5 pF of down-state capacitance (C_d). Also, an X-band microelectromechanical system (MEMS) switch with an insertion loss of less than 0.2 dB and an isolation of 35 dB is presented. This is done by inductively tuning the LC series resonance of the shunt switch. The MEMS bridge height is 1.5-2.5 μm, resulting in a pull-down voltage of 15-25 V. Application areas are in low-loss high-isolation communication and radar     

A fully integrated SOI RF MEMS technology for system-on-a-chip applications

In this paper, a silicon-on-insulator (SOI) radio-frequency (RF) microelectromechanical systems (MEMS) technology compatible with CMOS and high-voltage devices for system-on-a-chip applications is experimentally demonstrated for the first time. This technology allows the integration of RF MEMS switches with driver and processing circuits for single-chip communication applications. The SOI high-voltage device (0.7-/spl mu/m channel length, 2-/spl mu/m drift length, and over 35-V breakdown voltage), CMOS devices (0.7-/spl mu/m channel length and 1.3/-1.2 V threshold voltage), and RF MEMS capacitive switch (insertion loss 0.14 dB at 5 GHz and isolation 9.5 dB at 5 GHz) are designed and fabricated to show the feasibility of building fully integrated RF systems. The performance of the fabricated RF MEMS capacitive switches on low-resistivity and high-resistivity SOI substrates will also be compared.     

单刀双掷RF MEMS开关的研究与设计

介绍了一种基于横向金属接触的DC-5GHz单刀双掷RF MEMS开关的研究与设计．横向金属接触开关包括了一套有限的共面波导（FGCPW）传输线和左右摆动的悬臂梁．为了降低开启电压,设计了一种曲折型的折叠梁结构,通过理论分析与仿真实验验证了该结构的可行性,并利用MetalMUMPs工艺加以实现．测试结果显示,该开关在5GHz处的插入损耗为0．8dB,回波损耗大于20dB,隔离度为40dB．测得最低开启电压为33V．     

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     

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。