In modern military operations the requirements of transmitting large amounts of information have increased substantially during the last decade. This increases the demand for high-capacity radio networks. It is also very important that military decisions are made on recent and correct information and this implies that low and known delays are required. The existing military radio ommunications, within the Swedish army, do not meet the requirements for capacity and delay. We have investigated how the capacity and average delay can be improved in an Ad Hoc network with STDMA by using Antenna arrays.

This report describes a master thesis performed at Saab in Arboga. The main purpose was to build a controller for a system containing a turn table and an antenna beam. The idea is to use this system on a boat where it will be exposed to position disturbances due to waves. The desired behaviour is that antennas placed on the antenna beam should point towards the same target all the time. To solve this problem the system has been modeled and simulated in Matlab and Simulink.

During the work at Gateway Security AB in Motala I began examining available antenna models to get a wider perspective, this have given knowledge of their structure, and an understanding of their function. All my necessary fact is based on my observations and notes of these measurings. New antenna models, and available models were examined where measurements at different heights and different distances on the antenna were performed with the help of an oscilloscope and a measure probe, peak ? to - peak was brought on the signal. The measurements are presented in a line diagram.

This report describes the construction work of a radar antenna for the radar systemCARABAS. CARABAS is a long wave airborne ground radar that has been developed bySAAB Microwave Systems and will now be mounted on a small helicopter, Schweizer 300.The antenna should be able to fold up and down. When the radar is in use the antenna islowered and under transport, start and landing the antenna is folded up. An emergency dropfunction should also be included in the design of CARABAS III.The extent of this report includes construction of the antenna, frame structure attached to thehelicopter, mechanism for folding the antenna up and down and mechanism for emergencydrop function. The mechanical design of the antenna and frame structure is based on modaland stress analysis, vibration measurement of Schweizer 300 and frequency analysis, andcalculations regarding aerodynamic drag and mechanics.The exciting frequencies of the helicopter and accelerations at those frequencies weredetermined by vibration measurement and frequency analysis.

The work that is the basis of this Master Thesis was performed on Scania´s group of cabdevelopment, and concerns the GPS-system in Scania´s trucks. Today, the GPS-systemconsists of an active antenna mounted on the roof of the truck. The antenna is connectedto the receiver with a coaxial cable.The purpose with this Master Thesis was to develop and evaluate a new GPS-system,where the information is distributed using a LIN-network. Today, each unit requiringGPS-information is equipped with its own antenna and receiver. This solution has beenthe most cost effective to this point.

The task in this master thesis was to design and construct a prototype of a satellite antenna driver unit. The unit is to be robust and work in cold weather down to -40°C, so that it can be mounted on the roof of a minibus. A microcontroller controls the H-bridges simultaneous, each connected to an electrical motor. Hardware and software protections were implemented to ensure that the antenna can not turn outside its allowed area and risk breaking. The unit can output voltages at many different levels and communicate at a multitude of signal standards..

For several years Uppsala University together with several companies has been involved in a WISENET project aimed at improving railway transport security. By placing a sensor system near the wheels of each wagon, the temperature of the bearings can be measured and transmitted to a collector placed centrally on the wagon. This in turn transmits the collected data to RFID receivers placed intermittently along the railway.As the signals are transmitted wirelessly, problems may occur as the antennas get dirty or coated with ice and snow. To determine the effects of these coatings, several tests were performed examining the reflection coefficient S11, the impedance Z11 and the efficiency eta of an antenna, and how they varied when various coatings were placed over the antenna. Examined coatings were ice, snow and water to determine the effects of weather, and various metal-based coatings: powdered iron both pure and partially oxidized, and iron ore granules.

In this study I investigated whether the strength in the manual response for emotional and neutral stimulus search arrays can explain some of the difference in reaction times (RT:s) for emotional stimuli, or not. Earlier, perceptual, cognitive and attentional processes has mostly been used to explain the variance in RT:s. Thirtythree individuals were asked to, as fast as possible, detect a target picture among distractor pictures in 3 rows x 4 columns arranged search arrays. The pictures were categorized in fear relevant animals (snake, spider) and neutral animals (cat). The results showed, more correct responses for cat target.

This Master's Thesis describes the design of a new system where a digital signal processor has been added to an existing imaging system consisting of field programmable gate arrays. The new system will offer a higher degree of flexibility by considerably shortening the design time and make it possible to implement more complex algorithms than the existing ones. The choice of system architecture and a test implementation are discussed. The test implementation consists of a program for the digital signal processor and VHDL code for one of the field programmable gate arrays. The code for the digital signal processor was designed for testing on an evaluation board from Texas Instruments.

This report studies the possibility of using some sort of radio sender and transmitter in order to position skis lost in powder snow. It is concluded that a RF-solution on the 433 MHz frequency should be the most efficient. Different forms of directional antennas are examined and studies show that in theory the best suited is the so called ?Yagi-Uda antenna?. A solution based on using a Receive Signal Strength Indicator value together with the above mentioned directional antenna is developed.

For several years Uppsala University together with several companies has been involved in a WISENET project aimed at improving railway transport security. By placing a sensor system near the wheels of each wagon, the temperature of the bearings can be measured and transmitted to a collector placed centrally on the wagon. This in turn transmits the collected data to RFID receivers placed intermittently along the railway.As the signals are transmitted wirelessly, problems may occur as the antennas get dirty or coated with ice and snow. To determine the effects of these coatings, several tests were performed examining the reflection coefficient S11, the impedance Z11 and the efficiency eta of an antenna, and how they varied when various coatings were placed over the antenna. Examined coatings were ice, snow and water to determine the effects of weather, and various metal-based coatings: powdered iron both pure and partially oxidized, and iron ore granules.

For several years Uppsala University together with several companies has been involved in a WISENET project aimed at improving railway transport security. By placing a sensor system near the wheels of each wagon, the temperature of the bearings can be measured and transmitted to a collector placed centrally on the wagon. This in turn transmits the collected data to RFID receivers placed intermittently along the railway.As the signals are transmitted wirelessly, problems may occur as the antennas get dirty or coated with ice and snow. To determine the effects of these coatings, several tests were performed examining the reflection coefficient S11, the impedance Z11 and the efficiency eta of an antenna, and how they varied when various coatings were placed over the antenna. Examined coatings were ice, snow and water to determine the effects of weather, and various metal-based coatings: powdered iron both pure and partially oxidized, and iron ore granules.

This report deals with RFID systems and how to detect nearby tags with the Mifare standard using only a microcontroller and an antenna circuit.The aim was to investigate whether there was any possibility to continuously search for a nearby tag for a system operated with batteries without compromising   the lifespan of the battery. At this time the system would take too long time to wake up and look for a tag to give a satisfactory battery lifespan, which should be done a couple of times every second.The report has two issues, namely:Is it possible to direct the microprocessor to detect and identify a nearby tag after the Mifare standard?What hardware is required for this to be possible?As the research method to provide answers to the above questions an action research was used. This approach has meant that the group worked on information retrieval, examined existing solutions, tested their own solutions and documented the results.The group examined an existing solution that can search for nearby tags with minimal energy consumption. An antenna circuit was built that was connected to the processor.

This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards.

Syftet med denna rapport är att undersöka om det går att integrera en inomhusantenn i ett textilt material. Rapporten utgår från en design breif från företaget Teracom Group som är en del av kampanjen ?The Optimal Indoor Antenna?. Problemet som uppstått är att Boxer Danmark anser att den danska populationen inte tycker att de befintliga inomhusantennerna är tillräckligt estetiskt tilltalande. Detta problem har det forskats kring genom litteraturstudier, empiriska studier, material- och designstudier samt produktutveckling.