RF MEMS Single-Pole-Multi-Throw Switching Circuits

Hexagonal Shape radiating patch with reconfigurable characteristics for WiMAX/C/WLAN band is presented which is simulated on RT Duroid5880 substrate and is fed by CPW. Fractional bandwidth of antenna corresponds to 153.62% with high rejection dual band-notch reconfigurable characteristics excluding interfering bands WiMAX (3.30GHz–3.80GHz)/C-Band (3.80GHz–4.20GHz)/WLAN (IEEE802.11a/h/j/n5.15GHz–5.35GHz, 5.25GHz–5.35GHz, 5.47GHz–5.725GHz,5.725GHz–5.825GHz) using radio frequency micro electro mechanical systems (RF MEMS) shunt switch. The proposed antenna exhibits 3.4dBi–6.32dBi gain and 78–94% radiation efficiency. The group delay ≤1.0ns is also maintained in the entire operating band. Good dipole like radiation pattern in E-plane and omni-directional pattern in H-plane is also well maintained in the operating band with less co polarization with compact dimensions of 20 × 22 × 0.782 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

This paper proposes a series of optimized scalable contact-capacitive radio frequency micro- electro-mechanical systems (RF MEMS) switches for millimeter wave applications. Due to the contact-capacitive topology, the ON-state and OFF-state of the switch can be designed separately to obtain smaller <inline-formula> <tex-math notation="LaTeX">$C_{ON}$ </tex-math></inline-formula> and larger <inline-formula> <tex-math notation="LaTeX">$C_{OFF}$ </tex-math></inline-formula>, which results in high capacitance ratio (<inline-formula> <tex-math notation="LaTeX">$C_{r}$ </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">$C_{ON}$ </tex-math></inline-formula> is defined by capacitance of the contacts, and it is optimized for low insertion loss (<inline-formula> <tex-math notation="LaTeX">$IL_{ON}$ </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">$C_{OFF}$ </tex-math></inline-formula> is defined by the metal-insulator-metal (MIM) capacitor, and it is designed for working band and scalable performance. The measurements of the fabricated devices show acceptable agreements with design and simulation. The optimized switches perform well with <inline-formula> <tex-math notation="LaTeX">$IL_{ON}$ </tex-math></inline-formula> better than 1.5dB and capacitive ratio about 124. The switches follow scaling rules from 20GHz to 110GHz. Linearity (IIP3) of the switches are tested to be higher than 60dBm, and calculated to be higher than 80dBm. Performances of the switch can be further improved and optimized in the future study.

Epoxy based photo polymer - SU8 is evaluated as microwave packaging material for packaging of Radio Frequency Micro Electro Mechanical Systems (RFMEMS). Standard and Slotted Coplanar Waveguide transmission lines are chosen as test vehicles. Transmission lines of lengths up to 10mm are formed on ST-Cut Quartz substrates. The fabricated transmission lines are subjected to wafer level packaging. The measured S-parameter data shows a significant difference prior to and after packaging. Further, the effects due to the packaging are modeled using lumped components and the measured data are validated with simulations in Advanced Design System. The measured and simulated data agree favorably with each other, for both before and after packaging.

Radio Frequency Micro Electro Mechanical Systems (RF MEMS) are devices showing exceptional potential to satisfy the demands of emerging RF electronic technologies, including those considered for high-power applications, such as for long distance communication systems. Operation in this regime requires an alternative way of thinking for these devices and, for example, a more accurate control of the pull-in voltage is of major importance due to the self-actuation effect. Therefore, the studies focusing on the features of the moving bridges are of great importance. This work presents the fabrication of a full family of RF MEMS switches suitable for high-power implementations having bridges deposited by Au electroplating and released using purely standard wet processes, as well as a carefully designed experimental study of their pull-in voltage. Depositing the bridge of the high-power RF MEMS by using only a single electroplating step makes the device fabrication easier, whilst the utilization of a purely wet release process is an asset. This method relies on low temperature processes, applicable simultaneously in bridges with various geometrical and perforation details without the need of any specialised infrastructure. The experimentally obtained results suggest that for this technology the bridge thickness is a critical factor for controlling the pull-in characteristics between devices fabricated in the same run. Moreover, it is revealed that for thicker bridges, geometry and hole perforation effects are more pronounced. This technology is therefore suitable for developing RF MEMS where the bridge thickness could be potentially utilized for enabling optimization engineering between devices that should be fabricated in the same run but need to satisfy diverse specifications during their operation.

We report a radio frequency micro electromechanical system (RFMEMS) device integrated with phononic crystals (PnC) that provide a Lamb-wave resonator with frequency-selective heat management, power handling capability, and more efficient electromechanical coupling at ultra high frequency (UHF) and low microwave bands. The integrated device is fabricated in a silicon-on-insulator (SOI) aluminum nitride (AlN) platform and boosts thermal performance by 40%, power handling by 3 dB, and coupling coefficient by three times. Design approach is scalable to higher frequencies.

The regular down scaling in integrated circuits technologies stimulates the development of new solutions to increase the integrated circuit performances. Most efforts on size shrinking have been focused on active devices. Among technical solutions, the design and manufacturing of highly reliable integrated passive devices could be particularly relevant. Indeed, dielectrics thin films are used in a wide range of capacitive devices such as Metal Insulator Metal (MIM) capacitors, Metal Oxide Semiconductor (MOS) capacitor, gate for transistors and Memory applications or Radio Frequency Micro Electro MechanicalSystems(RFMEMS)switchingcapacitors.Theelectrical

To determine a micro electro mechanical systems (MEMS) inductor configuration that gives large inductance variations and high Q-factors, air-suspended MEMS inductor configurations are studied: (a) an inductor with two angularly meandered lines, (b) a solenoid inductor with a pair of movable shields, (c) a planar spiral inductor with a patterned shield of different areas, and (d) a planar spiral inductor with a metallic frame of different sizes. The configuration of (a) is shown to give a large inductance variation of 115%. However, its Q-factor is only about 10, and difficulties in fabrication are also expected. The configuration of (b) could be a reasonable engineering solution. The inductance variation is 67%, and the maximum Q-factor is over 22. The solenoidal inductor configuration is thus considered suitable for realizing an RF MEMS variable inductor with large inductance variations and high Q-factors.

RF MEMS (radio frequency micro electro mechanical systems) technology holds great promise for wireless communication and sensor systems. Excellent MEMS switching devices have recently been developed, but because of packaging problems, no commercial integrated product exists. The objective of the ongoing work at CFD Research Corporation (CFDRC) and Morgan Research Corporation (MORGAN) is to develop novel packaging concepts, design tools, and demonstrated RF MEMS packaged devices for high frequency applications.

Design, fabrication and characterization of miniature RF MEMS switched capacitor based phase shifter

We propose a capacitive shunt switch based on the inverted microshield transmission line. A 0.1 mumm thick aluminum nitride film covering an area of 149.1 times 150 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> can be deposited on the signal metal strip. A thin gold beam of thickness 1.5 mum, width of 150 mum and length of 370 mum is fixed on both ends with two gold anchors of height 3 mum. We performed FEM simulations on the MEMS switch with HFSS. The scattering parameters of open and closed MEMS shunt switch. The insertion loss is less than 0.94 dB and the isolation is about 80 dB around 35 GHz. The capacitive MEMS shunt switch based on the inverted microshield line can be fabricated with low resistivity silicon. It has excellent high frequency performance and it has some advantages over conventional microshield transmission lines (Dib and Katehi, 1992)

Design and fabrication of a folded leg Ka-band RF micro electro mechanical systems (RF MEMS) is presented. The mechanical design is carried out to observe minimum permanent deformation on the MEMS bridge after our in-house MEMS packaging process temperature treatment (200 °C). On the other hand, the actuation voltage is aimed as <30 V and measured as 24---25 V before thermal treatment. Moreover, the switch shows 28---29 V actuation voltage after thermal treatment. The fabricated switch shows ź0.4 dB insertion loss for the up state position at Ka-band, before and after heat treatment. The switch is fabricated on quartz wafer using an in-house surface micromachining process with a new amorphous silicon sacrificial layer structure.

A vertical RF-MEMS (Radio Frequency Micro ElectroMechanical Switch) switch design is proposed in this work that features a shunt capacitive configuration and can operate at a very low actuation voltage. Besides operating on a low switching voltage, the switch behold a small value of insertion loss in Up (ON) state and offers a towering isolation factor in Down (OFF) state. A horizontal structure of bridge membrane is used in the proposed design and the switch function (with ON and OFF operating states) is provided by the vertical movement of this membrane structure that is controlled by the electrostatic actuation technique. The actuation pad is centrally fed by a Coplanar Waveguide structure. The switch performance has been analysed over a wide frequency range from 1 to 40 GHz. For obtaining a 1.5 μm vertical displacement of the bridge membrane, a sheer 3.0 Volts of pull-in voltage (VPI) is required. CoventorWare and HFSSv13 tools are used in this work for designing and analysing the proposed switch. The use of fixed-fixed flexure beam configuration is chosen for switch design. Simulation results showcase excellent RF characteristics with isolation factor of −47 dB (at 32.5 GHz) and insertion loss in range of −0.01 to −1.10 dB (for 1−40 GHz frequency).

We propose a design, micro fabrication process, and nuclear magnetic resonance (NMR) based evaluation, of a magnetic field gradient chip. The uni-axial linear z-gradient coil design was computed by a stream-function method, with the optimisation goal to exhibit minimum power dissipation. The gradient coils were implemented on two bi-planes, which were built-up with Cu electroplating in combination with photo definable dry-film laminates. In the presented fabrication process, the initial seed layer served as a self-aligning back-side mask to define the electroplating mould, and also to implement resistive temperature detectors. The coil design and the electroplating process were tailored to enhance the electroplated height to construct low-resistive coils. Thermographic imaging in combination with the integrated temperature sensors allowed for investigating the heat-up, in order to analyse the current rating of the coil dual stack. The gradient coil was assembled with a radio frequency micro coil in a flip-chip configuration. To demonstrate the field linearity, a micro-engineered phantom was fabricated and subjected to a one-dimensional NMR experiment.

This work presents wide range of compact and reliable single-pole-multi-throw (SPMT) radio frequency (RF) microelectromechanical system (MEMS) switches where the M (output) varies from 3 to 14 throws. The single dc-contact switch dimensions are 0.144 mm × 0.29 mm which are fabricated on 635 µm alumina substrate using a surface micromachining process. SPMT switching networks demonstrate a measured return loss of more than 14 dB, a worst case insertion loss of ~1.76 dB and isolation of ~14.5 dB up to 12 GHz. The maximum area of the fabricated SPMT switch is ~1.2 mm2. The SPMT switches are capable of handling 1 W of RF power up to >1 billion cycles at 25 °C, and sustained even up to >80 million cycles with 0.5 W at 85 °C. To the best of our knowledge, this is the first reported wide range of MEMS SPMT switches and their respective performance evaluations in the literature that has undergone extensive measurement stages.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new kind of double- and single-arm cantilever type DC-contact RF MEMS actuators has been monolithically integrated with an antenna architecture to develop a frequency reconfigurable antenna. The design, microfabrication, and characterization of this “reconfigurable antenna (RA) annular slot” which was built on a microwave laminate TMM10i (<formula formulatype="inline"> <tex Notation="TeX">$\varepsilon _{r} $</tex></formula> = 9.8, <formula formulatype="inline"> <tex Notation="TeX">$\tan \delta $</tex></formula> = 0.002), are presented in this paper. By activating/deactivating the RF MEMS actuators, which are strategically located within the antenna geometry and microstrip feed line, the operating frequency band is changed. The RA annular slot has two reconfigurable frequencies of operation with center frequencies <formula formulatype="inline"> <tex Notation="TeX">$f _{\rm low} $</tex></formula> =2.4 GHz and <formula formulatype="inline"><tex Notation="TeX">$f _{\rm high} $</tex></formula> = 5.2 GHz, compatible with IEEE 802.11 WLAN standards. The radiation and impedance characteristics of the antenna along with the RF performance of individual actuators are presented and discussed. </para>