Saab AB

About: Saab AB is a company organization based out in Thun, Switzerland. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 862 authors who have published 928 publications receiving 8807 citations. The organization is also known as: Saab AB & Svenska Aeroplan AB.

Impact of AlGaN/GaN Interface and Passivation on the Robustness of Low-Noise Amplifiers

Abstract: Poststress dc characteristics of AlGaN/GaN HEMTs can be used to study the effect of high-power stress on the noise figure (NF) and gain of low-noise amplifiers (LNAs) subjected to large input overdrives. This enables a shift from circuit- to transistor-level measurements to investigate the impact of variations in HEMT design parameters on the robustness (including both recovery time and survivability) by mimicking LNA operation. Using this method, a tradeoff between survivability and recovery time is demonstrated for different AlGaN/GaN interface profiles (sharp interface, standard interface, and AlN interlayer). Furthermore, the impact of different surface passivation schemes (Si-rich, Si-poor, and bilayer SiN x ) on robustness is investigated. The bilayer passivation, which features low leakage current and small gain compression under overdrive stress, exhibits relatively weak survivability. The mechanisms influencing the robustness are analyzed based on transistor physics. The short recovery time is mainly due to impeding the injection of hot electrons into surface traps and high reverse current, whereas the survivability is dependent on the local or global peak electrical fields around the gate under high power stress.

System and method for maintenance

Abstract: This invention concerns a system for maintaining equipment (2a, 2b, 2c) housed in a vehicle (1). The equipment has means arranged so as to monitor the operation of the equipment, which monitoring means are connected to a recording unit (3) for recording detected operational deviations in the equipment. The system is further characterized in that, for at least one of the pieces of equipment (2a), the monitoring means (6) are arranged so as to monitor the execution of the software (7) incorporated in the equipment to detect occurrences of fault conditions and/or fault symptoms. The invention also includes a method for software maintenance.

Missile guidance system

Abstract: A missile guidance system and method for guiding a missile, mainly horizontally flying, to pass a target at a desired passage height.

Decentralized sensor fusion and support using multiple models

Abstract: In an aircraft application there are a number of limitations (limited computational capability, limited data bus bandwidth) on a sensor system as well as there are a number of requirements to fulfill to make the sensor system robust against jamming and other kinds of disturbances We are presenting a new approach to decentralized sensor fusion and tracking, where `decentralized' means that there are a considerable amount of pre-computation performed in the sensors The novelty of the approach lies in the way the information is fed back from the central fusion unit that is handling the information delivered by the sensors The information is fed back to the sensors to enable an improved tracking performance and at the same time not contaminating the sensor in the case the central fusion information is distorted due to jamming The algorithm is realized by using an extend version of the multiple models algorithm AFMM (same class of algorithms as the IMM), in combination with a decentralized Kalman filtering scheme The extension of AFMM consists of a possibility to include externally hypotheses in the regular split and prune mechanism This way the external information is treated the same way as a prior in a Kalman filtering scheme and thus the global track estimate is confronted with the sensor's view before accepted by the sensor In the paper the performance of the tracking algorithm is evaluated in a system consisting of a Radar and an Infrared search and track sensor

Synthesis of a Graphene Carbon Nanotube Hybrid Film by Joule Self-Heating CVD for Thermal Applications

Abstract: Hybrid films based on vertically aligned carbon nanotubes (CNTs) on graphene or graphite sheets have been proposed for application as thermal interface materials and micro heat sinks. However, the fabrication of these materials are limited to small scale, expensive and complicated chemical vapor deposition (CVD) for CNT synthesis. We present a new method for direct growth of CNTs on one or both sides of a thin graphene film (GF) using joule self-heating of the graphene film to provide the necessary heat for the thermal breakdown of carbon feedstock in a CVD process. The resulting CNT forests show good density and alignment consistent with regular CVD synthesis processes on silicon surfaces. The resulting double sided GF/CNT hybrid film is directly applicable as a thermal pad. The CNT forest has a thermal conductivity of 30 W/mK, measured by pulsed photothermal reflectance, and the total thermal interface resistance between aluminum blocks was measured to be 60 Kmm^2/W using an ASTM D5470 compliant 1-D measurement setup. This method of directly synthesizing CNTs on graphene films is more energy efficient and capable of larger volume production compared to traditional CVD methods. It is also compatible with scaling up towards continuous roll-to-roll production for large scale commercial production, one of the major limitations preventing CVD-grown CNTs from commercial applications.