A micro-electro-mechanical series (MEMS)-switched parasitic antenna array providing radiation pattern diversity is described. A new modeling method is introduced in order to allow a fast and accurate optimization of the antenna. This method is demonstrated with the design of both passive and active prototypes at 5.6 GHz. The active prototype makes use of stand-alone packaged MEMS switches. Measured return loss and radiation patterns are in good agreement with the design, demonstrating a beam-switching at plusmn25deg

MEMS-Switched Parasitic-Antenna Array for Radiation Pattern Diversity

We designed, fabricated and measured the performance of nanoelectromechanical (NEMS) switches. Initial data are reported with one of the switch designs having a measured switching time of 400 ns and an operating voltage of 5 V. The switches operated laterally with unmeasurable leakage current in the 'off' state. Surface micromachining techniques were used to fabricate the switches. All processing was CMOS compatible. A single metal layer, defined by a single mask step, was used as the mechanical switch layer. The details of the modeling, fabrication and testing of the NEMS switches are reported.

https://iopscience.iop.org/article/10.1088/0960-1317/19/8/085003/pdf

A nanomechanical switch for integration with CMOS logic

This paper presents fast switching RF microelectromechanical systems (MEMS) capacitors with measured switching times between 150-400 ns. By introducing bent sides on a planar microbeam, it is shown experimentally that the resonance frequency of aluminum bridges is increased by a factor of 25 compared to standard RF MEMS components. In addition, this original shape can be implemented easily in post-processing of complementary metal-oxide-semiconductor circuits. Several designs are presented with measured mechanical resonance frequencies between 1-3 MHz and measured switching times under 400 ns. Using this original approach, sub-microsecond RF MEMS switched capacitors have been designed and fabricated on quartz substrate. Their resulting RF performance is presented with a measured capacitance ratio of 2.3. Reliability tests have also been performed and have demonstrated no significant mechanical behavior variation over 14 billion cycles and a moderate sensitivity to temperature variation.

Sub-Microsecond RF MEMS Switched Capacitors

This paper presents an electrostatic RF microelectromechanical systems (MEMS) metal contact switch based on a tethered cantilever topology. The use of tethers results in a design that has low sensitivity to stress gradients, biaxial stresses, and temperature. A switch with a footprint of 160 × 190 μm2 and based on a 8-μm-thick gold cantilever with an Au/Ru contact is implemented on a high-resistivity silicon substrate and results in a total contact force of 0.8-1.2 mN at 80-90 V, a restoring force of 0.5 mN, a pull-in voltage of 61 V, an up-state capacitance of 24 fF, and an actuation time of 6.4 μ s. The device achieves a switch resistance of 2.4±1.4 Ω to 1.8±0.6 Ω at 90-100 V in open laboratory environments (nonpackaged). This design has the potential to replace conventional electromagnetic relays in application areas such as automated testing equipment and high-performance switching networks.

RF MEMS Metal-Contact Switches With mN-Contact and Restoring Forces and Low Process Sensitivity

This paper presents the robust design optimization of an RF-MEMS direct contact cantilever switch for minimum actuation voltage and opening time, and maximum power handling capability. The design variables are the length and thickness of the entire cantilever, the widths of the sections of the cantilever, and the dimple size. The actuation voltage is obtained using a 3-D structural-electrostatic finite-element method (FEM) model, and the opening time is obtained using the same FEM model and the experimental model of adhesion at the contact surfaces developed in our previous work. The model accounts for an unpredictable variance in the contact resistance resulting from the micromachining process for the estimation of the power handling. This is achieved by taking the ratio of the root mean square power of the RF current (ldquosignalrdquo) passing through the switch to the contact temperature (ldquonoiserdquo) resulting from the possible range of the contact resistance. The resulting robust optimization problem is solved using a Strength Pareto Evolutionary Algorithm, to obtain design alternatives exhibiting different tradeoffs among the three objectives. The results show that there exists substantial room for improved designs of RF-MEMS direct-contact switches. It also provides a better understanding of the key factors contributing to the performances of RF-MEMS switches. Most importantly, it provides guidance for further improvements of RF-MEMS switches that exploit complex multiphysics phenomena.

/pdf/robust-design-of-rf-mems-cantilever-switches-using-contact-40c16jioef.pdf

Robust Design of RF-MEMS Cantilever Switches Using Contact Physics Modeling

This paper presents a wideband ohmic shunt switch implemented on a coplanar waveguide (CPW). The switch is fabricated using a dielectric membrane with patterned metallic contacts that short the CPW line when it is electrostatically actuated. The switch has been extrapolated from measurements. It exhibits low insertion loss, good matching, high isolation from DC to W band (>20 dB up to 100 GHz) and very good mechanical properties with switching time <1/spl mu/s.

C. Zanchi

Papers

A DC to 100 GHz high performance ohmic shunt switch