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A novel design of a highly sensitive wireless passive RF strain transducer is presented based on a patch antenna loaded with an open loop that is capable of sensing strain independently in two directions. An original idea of utilizing a cantilever at the gap of the open loop significantly improves the sensitivity of resonant frequency shifts. The frequency shifts in two distinct resonant modes are detected based on two dominant orthogonal modes of the patch resonators. In measurements, the prototypes achieved a sensitivity of 2.35% frequency shift per 1% strain, more than twice that of existing strain transducers of the same class. In simulations, the new design achieved a theoretical sensitivity up to four times as high as existing designs of RF passive wireless strain transducers. The ground plane allows for the sensitivity of the sensor to be independent from the applied surface. An implementation example of the passive remote sensing system based on the proposed strain transducer is also discussed as a proof-of-concept case. Based on calculations, the interrogation method in the example shows a radar cross section fluctuation of 3.8 dB corresponding to the strain induced at the sensor. [ABSTRACT FROM AUTHOR]

In this paper a new procedure for the spiral Marchand balun design is shown and demonstrated. The size reduction for this component is fundamental to obtain a high level of integration for the radio frequency analog circuits. This work shows a micro-structure that, working as a balun, achieves good performance in phase and amplitude balance, while maintaining minimum size. These results were achieved by performing an accurate theoretical analysis followed by an electromagnetic simulation of the structure. A set of equations are proposed to describe the component behavior and the measurements show a strong agreement with the simulations confirming the quality of the design flow. The balun shows a maximum of 1.5 dB of insertion loss, with 0.1 dB of amplitude imbalance. The phase imbalance reach as a maximum of 7° at 65 GHz. The total occupied area of the balun remain below to 0.01 mm. [ABSTRACT FROM AUTHOR]

At the present time, the insertion of radio frequency microelectromechanical switches into real architecture requires reduced actuation voltages, reduced dimensions, and better control of the electrical and electromechanical behavior that gives more importance to surface effects, their understanding, and modeling. The use of such devices requires the development of methods for estimating the contact performances as a function of surface roughness, contact materials, and contact topologies. With increase in computation capabilities, the rough surface topography can be implemented in the finite element model but implies long calculation times or even calculation overloading if a high definition of the roughness is desired. To reduce these limitations, assumptions on the microgeometry are required. This paper treats, by use of finite element modeling, the influence of the definition of roughness of contacting switch members on the electrical contact resistance of resistive switches, and investigates the error introduced by using a minimum defined atomic force microscope sampling interval of 10 nm. The present numerical analysis is implemented for switch test structures. [ABSTRACT FROM PUBLISHER]

This paper addresses an innovative solution to develop a circuit to perform accelerated stress tests of capacitive microelectromechanical-system (MEMS) switches and shows the use of instruments and equipment to monitor physical aging phenomena. A dedicated test circuit was designed and fabricated in order to meet the need for accelerated techniques for those structures. It integrated an in-house miniaturized circuit connected to additional test equipment (e.g., oscilloscopes and capacitance meters) that enabled the reliability characterization of capacitive switches. The accelerated stress test (AST) circuit generated an electrostatic-discharge-like impulse that stressed the device. This setup allowed the simultaneous measurement of the current and voltage waveforms, and the capacitance variation of the device under test after each stress. The results obtained using the miniature AST circuit were discussed and were correlated with results obtained using a commercial human-body-model tester as well as data from a cycling benchmark. The scope of this paper encompasses the theory, methodology, and practice of measurement; the development of a testing miniaturized board; and the analysis and representation of the information obtained from a set of measurements. As a result, it may contribute to the scientific and technical standards in the field of instrumentation and measurement of electrostactically actuated devices having insulating layers. [ABSTRACT FROM PUBLISHER]

The objective of this competition was to design, construct and demonstrate a working wireless communication architecture for software defi ned radio (SDR). The implementation had to contain at least one programmable device, the front-end analog RF circuitry, an analog-to-digital converter (ADC), and an analog output. This SDR student design contest required multiple disciplines. There was a need for skills in RF analog design and wave propagation for the front-end and the antennas, digital signal processing (DSP) for the physical layer, and network setup and protocols for the medium access control (MAC). A coordinated design effort in the different disciplines was necessary to ensure that the different parts work together. The main criteria for judging were innovation and success of reaching the goals that the student team had set. The target of this subject was based on a real aeronautic industry demand concerning real time, synchronized and high data-rate instrumentation wireless sensor network for in-flight aircraft test. [ABSTRACT FROM PUBLISHER]

Abstract: This paper presents a circuit used to actuate Radio Frequency MicroElectroMechanical Systems (RF MEMS) based phase shifters for 60GHz beam forming. Wireless transmission in the 60GHz band show a dramatic free space loss, thus making it mandatory to use antennas with high gain in a desired direction. Beam forming is then necessary to optimize the link budget between communicating nodes. Antenna arrays can be used for beam forming. The work done at LAAS was aiming to provide RF MEMS based phase shifters working with a standard digital command. RF MEMS commonly have high actuation voltages usually obtained with charge pumps. This paper presents a full 1bit phase shifter with a digital translation part, an analog DC–DC converter, and an RF MEMS based loaded line phase shifter for 60GHz signals. This converter is built using boost converters as an alternative to the use of charge pumps for driving RF MEMS in the field of wireless communications. Boost converters, despite relatively high current peaks, allow shorter settling times compared to charge pumps. [Copyright &y& Elsevier]

Abstract: The reliability of integrated systems is considered as a major obstacle in their development. The goal of this work is to estimate the lifetime of RF MEMS capacitive switch devices. This is performed by combining the functional and physical failure analysis models using the VHDL-AMS language. The physics of charging effects along with mechanical behavior of the membrane are introduced simultaneously to determine the time to failure. [Copyright &y& Elsevier]