RF MEMS ohmic switches for matrix configurations

Two different topologies of radio frequency micro-electro-mechanical system (RF MEMS) series ohmic switches (cantilever and clamped–clamped beams) in coplanar waveguide (CPW) configuration have been characterized by means of DC, environmental, and RF measurements. In particular, on-wafer checks have been followed by RF test after vibration, thermal shocks, and temperature cycles. The devices have been manufactured on high resistivity silicon substrates, as building blocks to be implemented in different single-pole 4-throw (SP4 T), double-pole double-throw (DPDT) configurations, and then integrated in Low Temperature Co-fired Ceramics (LTCC) technology for the realization of large-order Clos 3D networks

Scaleable CMOS current-mode preamplifier design for an optical receiver

We have designed a process-insensitive preamplifier for an optical receiver, fabricated it in several different minimum feature sizes of standard digital CMOS, and demonstrated design scaleability of this analog integrated circuit design. The same amplifier was fabricated in a 1.2 mu m and two different 0.8 mu m processes through the MOSIS foundry [1]. The amplifier uses a multi-stage, low-gain-per-stage approach. It has a total of 5 identical cascaded stages. Each stage is essentially a current mirror with a current gain of 3. Three of these preamplifiers have been integrated with a GaAs Metal-Semiconductor-Metal (MSM) photodetector and one with an InGaAs MSM detector by using a thin-film epilayer device separation and bonding technology [2]. This quasi-monolithic front-end of an optical receiver virtually eliminates the parasitics between the photodetector and the silicon CMOS preamplifier. We have demonstrated speed and power dissipation improvement as the minimum feature size of the transistors shrinkclose

PATTERN RECONFIGURATION OF MICROSTRIP ANTENNA USING FLIP-CHIP MOUNTED PACKAGED MEMS

International audienceThis work describes the design of a radiation pattern reconfigurable microstrip antenna electrically controlled by packaged Radio frequency micro-electro-mechanical system (RF MEMS). The antenna operates at 12 24 GHz with good return loss characteristics and a similar to 7 5 dB gain at +/- 30 degrees scan angles from broadside direction in the II-plane. The integratino of packaged RF MEMS and associated bias network is also explained. (C) 2010 Wiley Periodicals, Inc Microwave Opt Technol Lett 52 574-577, 2010. Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.2497

Reliability of dielectric less electrostatic actuators in RF-MEMS ohmic switches.

International audienc

NaLa(SO4)2,H2O thermal conversion and Na3La(SO4)3 crystal growth

International audienceNaLa(SO4)2,H2O crystalline powder was obtained under hydrothermal conditions at 220°C. A coupled TGA/DTA experiment of NaLa(SO4)2,H2O exhibits a weight loss at 260°C corresponding to the dehydration and an endothermal peak at 774°C. To elucidate the transformation mechanism as a function of temperature, single crystals have been grown at 80°C, 300 and 800°C. For each phase, single crystals have been isolated and structure determination was performed. As already published, NaLa(SO4)2,H2O crystallizes in a P3121 space group. However, the dehydration at 260°C is not a simple loss of the water molecule but a radical change in the structure. The removal of the water molecules inside the tunnels formed by the framework leads to a change in the coordination of the LaO9 Lanthanum-based polyhedrons. The compound obtained after dehydration is a new triple sulfate of the formula Na3La(SO4)3 crystallizing in the R-3 space group (a = 14.0976(1) Å; c = 8.1267(1) Å) with LaO12 icosahedrons. Millimeter size single crystals of this new phase have been grown under hydrothermal conditions (300°C, 157 bars). After the endothermal peak at 774°C, Na3La(SO4)3 decomposes by forming the anhydrous double sulfate NaLa(SO4)2 crystallizing in the P-1 space group with LaO10 polyhedrons. The structure of the three (NaLa)-compounds at RT, 300°C and 800°C is compatible with the expected Raman signatures. Finally, a complete transformation of NaLa(SO4)2,H2O up to 800°C is proposed. After 1000°C, the compound decomposes chemically with a large weight loss