Saab Automobile AB

About: Saab Automobile AB is a based out in . It is known for research contribution in the topics: Radar & Antenna (radio). The organization has 760 authors who have published 890 publications receiving 11811 citations.

Method and system for tracking position of an object using imaging and non-imaging surveillance devices

Abstract: A method and system for tracking the position of objects, such as aircraft and ground vehicles around an airport. A transmission from the object is received at a non-imaging surveillance device of known location, the transmission being used to determine the coordinate position of the object within a given time period. Image data for the object is captured by an imaging surveillance device of known location to provide an image of the object within the same given time period. The coordinate position is correlated with the image to provide composite data about the object within the same given time period. The composite data is displayed to a viewer as a visual depiction of the object.

High frequency characteristics of liquid crystal polymer for system in a package application

Abstract: Liquid crystal polymer (LCP) is a promising substrate for electronics packaging. In this paper, the high frequency characteristics of LCP were investigated using a microstrip ring resonator to verify the possibility of the application of the material in microwave packaging. A GaAs MMIC switch circuit was fabricated using LCP as substrate to demonstrate an application of this material for system in a package. From the high frequency measurements, it is shown that LCP has low dielectric constant and low loss tangent that make it useable in high frequency packaging.

Increasing ZigBee network lifetime with X-MAC

Abstract: The ZigBee standard builds on the assumption that infrastructure nodes have a constant power supply. ZigBee therefore does not provide any power-saving mechanisms for routing nodes, which limits the lifetime of battery-powered ZigBee networks to a few days. This short lifetime drastically restricts the possible application scenarios for ZigBee. To expand the usefulness of ZigBee, we present a ZigBee implementation where we replace the default ZigBee MAC protocol with the power-saving MAC protocol X-MAC. Our results show that X-MAC reduces the power consumption for ZigBee routing nodes with up to 90%, leading to a ten-fold increase in network lifetime at the price of a slight increase in network latency. Furthermore, we are the first to experimentally quantify the energy-efficiency of X-MAC in a multihop scenario. Our results indicate that X-MAC reduces the power consumption of idle nodes that are within communication range of two communicating nodes, suggesting that X-MAC may be able to mitigate the hot-spot problem in sensor networks.

Excitation properties of the divacancy in 4H -SiC

Abstract: We investigate the quenching of the photoluminescence (PL) from the divacancy defect in $4H$-SiC consisting of a nearest-neighbor silicon and carbon vacancies. The quenching occurs only when the PL is excited below certain photon energies (thresholds), which differ for the four different inequivalent divacancy configurations in $4H$-SiC. An accurate theoretical ab initio calculation for the charge-transfer levels of the divacancy shows very good agreement between the position of the (0/\ensuremath{-}) level with respect to the conduction band for each divacancy configuration and the corresponding experimentally observed threshold, allowing us to associate the PL decay with conversion of the divacancy from neutral to negative charge state due to capture of electrons photoionized from other defects (traps) by the excitation. Electron paramagnetic resonance measurements are conducted in the dark and under excitation similar to that used in the PL experiments and shed light on the possible origin of traps in the different samples. A simple model built on this concept agrees well with the experimentally observed decay curves.