Design Considerations for Compact Mobile Ku-Band Satellite Terminals

Phased array technology is becoming a commercially important market for mobile telecommunication applications, e.g. mobile satellite terminals. Such systems, either for maritime, aeronautical or land applications, must be able to receive satellite broadcasting services on-the-move. Multimedia is here the driving force to develop cost-effective compact commercial terminals, favourably for various classes of applications, such as general or customised broadcasting services, for example. Such terminals are of special interest to the automotive industry because the terminals currently on the market for such applications are still partly based on mechanical moving parts, thus maintenance intensive, heavy and bulky, and subject to G-forces. These properties are not very appealing to the automotive industry where car aesthetics are ever so important. Far more favourable are the fully electronically steerable solutions that can be very compact and have very low maintenance. However, one of the major limitations and biggest design challenges of this type of phased array systems is the relatively high price due to its electronic complexity. The NATALIA project (New Automotive Tracking Antenna for Low-cost Innovative Applications) funded by ESA, is investigating the possibility of realizing a compact cost-effective solution for a receive- only full electronically steerable antenna for cars in Ku-band. The key items for the design of this antenna system are not only low-cost but also small size (around 20 cm in diameter and a height of a few em´s) so that the antenna can easily be integrated into or onto the structure of the car. Different concepts for the NATALIA antenna have been investigated such as RF-phase shifters in (M)MIC technology and different configurations of beam forming/switching networks, all evaluated with respect to complexity/costs, performance (G/T) and size, resulting into a first baseline design.