Row/Column Addressing Scheme for Large Electrostatic Actuator MEMS Switch Arrays and Optimization of the Operational Reliability by Statistical Analysis

This paper investigates the design and optimization of a row/column addressing scheme to individually pull in or pull out single electrostatic actuators in an N² array, utilizing the electromechanical hysteresis behavior of electrostatic actuators and efficiently reducing the number of necessary control lines from N² complexity to 27 V. This paper illustrates the principle of the row/column addressing scheme. Furthermore, it investigates the optimal addressing voltages to individually pull in or pull out single actuators with maximum operational reliability, determined by the statistical parameters of the pull-in and pull-out characteristics of the actuators. The investigated addressing scheme is implemented for the individual addressing of cross-connect switches in a microelectromechanical systems 20 X 20 switch array, which is utilized for the automated any-to-any interconnection of 20 input signal line pairs to 20 output signal line pairs. The investigated addressing scheme and the presented calculations were successfully tested on electrostatic actuators in a fabricated 20 X 20 array. The actuation voltages and their statistical variations were characterized for different subarray cluster sizes. Finally, the addressing voltages were calculated and verified by tests, resulting in an operational reliability of 99.9498% (502 parts per million (ppm) failure rate) for a 20 X 20 switch array and of 99.99982% (1.75 ppm failure rate) for a 3 X 3 subarray cluster. The array operates by AC-actuation voltage to minimize the disturbing effects by dielectric charging of the actuator isolation layers, as observed in this paper for DC-actuation voltages.     

On resonant effects in multilayer RF/microwave printed circuitboard applications

Multilayer printed-circuit boards (PCB's) are nowadays widely used in high-frequency technology applications. While their small dimensions, compact design and low cost are an obvious advantage, the impact of full-wave phenomena such as electromagnetic coupling, resonance or leakage increases substantially as the used frequency spectrum shifts toward and beyond the upper UHF band and the L-band (1-2 GHz). Two types of PCB structures exhibiting resonant properties are considered in this paper: PCB shielding covers and large split-ground conducting plates. These structures can cause narrow-band (resonant) cross-talk. Their behavior is studied by both numerical and analytical approaches, and simple techniques to predict possible resonant coupling are proposed     

BCB contact printing for patterned adhesive full-wafer bonded 0-level packages

Adhesive wafer bonding with a patterned polymer layer is increasingly attracting attention as cheap and simple 0-level packaging technology for microstructures, because the patterned polymer both fulfills the bonding function and determines the volumes between the two wafers housing the devices to be packaged. To be able to pattern a polymer, it has to be cross-linked to a certain degree which makes the material rigid and less adhesive for the bonding afterward. In this paper, a simple method is presented which combines the advantages of a patterned adhesive layer with the advantages of a liquid polymer phase before the bonding. The pattern in the adhesive layer is "inked" with viscous polymer by pressing the substrate toward an auxiliary wafer with a thin liquid polymer layer. Then, the substrate with the inked pattern is finally bonded to the top wafer. Benzocyclobuene (BCB) was used both for the patterned structures and as the "ink". Tensile bond strength tests were carried out on patterned adhesive bonded samples fabricated with and without this contact printing method. The bonding yield is significantly improved with the contact printing method, the fabrication procedure is more robust and the test results show that the bond strength is at least 2 times higher. An investigation of the samples' failure mechanisms revealed that the bond strength even exceeds the adhesion forces of the BCB to the substrate. Furthermore, the BCB contact printing method was successfully applied for 0-level glass-lid packaging done by full-wafer bonding with a patterned adhesive layer. Here, the encapsulating lids are separated after the bonding by dicing the top wafer independently of the bottom wafer.     

A Real-Time Image Recognition System for Tiny Autonomous Mobile Robots

Intelligent sensors for mobile robots play an important role in many technical applications. In this paper a real-time image recognition system for a tiny autonomous mobile robot is presented, capable of detecting objects in real-time at a frame rate of up to 60 frames/s. The image recognition module has very low power consumption of less than 250 mW and fits into a package of only 35 × 35 mm including a CMOS camera and a low power, high performance signal processor. We propose an object recognition algorithm that is optimized for deeply embedded systems used in energy and performance constrained devices. The algorithm is based on a combination of edge and color detection and uses a fixed model for each object to be recognized. Results of the ball recognition application show that its relative polar coordinates are found within 11 ms.Stefan Mahlknecht received a Masters degree in electrical engineering and a doctoral degree from Vienna University of technology. His doctoral thesis dealt with the topic of energy selfsufficient wireless sensor networks. He spend one year at the University of Illinois in Urbana Champain, where he focused on communication networks and protocols. Since 2001 he is a member of the departements staff. His research interests are devoted to the topic of wireless sensor networks, communication protocols, embedded systems and robotics.Roland Oberhammer is a master thesis student at the Institute of Computer Technology at the Vienna University of Technology. His master thesis dealt with the topic of real-time ball recognition on resource limited embedded platforms. His research interests are in the field of embedded systems and robotics.Gregor Novak received a Masters degree in mechanical engineering and a doctoral degree in technical sciences both from the Vienna University of Technology in Austria in the years 1997 and 2002, respectively as well as a Masters degree in engineering management in 2001 from Oakland University in USA. Presently he is the coordinator of the Vienna University of Technologys Center of Excellence for Autonomous Systems. His research focuses on autonomous mobile cooperating robots.     

Low-voltage high-isolation DC-to-RF MEMS switch based on an S-shaped film actuator

This paper presents a new electrostatically actuated microelectromechanical series switch for switching dc to radio frequency (RF) signals. The device is based on a flexible S-shaped film moving between a top and a bottom electrode in touch-mode actuation. This concept, in contrast to most other microelectrochemical systems (MEMS) switches, allows a design with a low actuation voltage independent of the off-state gap height. This makes larger nominal switching contact areas for lower insertion loss possible, by obtaining high isolation in the off-state. The actuation voltages of the first prototype switches are 12 V to open, and 15.8 V to close the metal contact. The RF isolation with a gap distance of 14.2 /spl mu/m is better than -45 dB up to 2 GHz and -30 dB at 15 GHz despite a large nominal switching contact area of 3500 /spl mu/m/sup 2/.