System design by simulation - a case study for sensor tags embedded in tyres

The implementation of ID functions and sensors in a tyre has been discussed intensively for some time past. Such an intelligent tyre is necessary to identify the manufacturer and the type of the tyre. Additionally, physical parameters of the tyre can be measured during use to warn the driver against possible damages or to test different tyres in a lab. The RFID technique is one possibility to realise such an application. During system design, there is a big challenge to answer at least two important questions. The first one is if the system would work with the selected antenna shapes, sizes and positions. And the second one is, which antenna design is more advantageous than others depending on power consumption of the tag, rim shape, size and material as well as using a steel cord in the tyre or not. Answering those questions in a correct way, within an appropriate amount of time and without doing a lot of prototyping is very difficult, because there are relations between electrical and electromagnetic models that must be considered carefully. This paper will focus on these challenges. It will show a way to analyse an inductively coupled transponder system that can be used for such an application. And it presents an approach for modelling and analysing the transmission channel as well as the electrical system behaviour including the influence of a metal rim and the steel cord. Additionally, a discussion is done concerning business value of such a design flow considering different RFID applications with other application specific requirements but finally the some challenges on system design