Next to the far field, the near field of an antennae is of great interest. In contrast to far field, the near field contains the reactive power which is not radiated. For this reason, the directional receiving pattern of the antenna has not yet been completely developed in this area. Using a scanner-based method, this defect can be eliminated. With a special near field scanner, the electromagnetic field in the immediate proximity of the antenna or circuit is scanned.
The magnitude and phase of the emitted signal are scanned with a special probe and read out in a network analyser. In this way, any possible interference or error sources can be localised on the antenna circuit board. Data established in the field simulation is used as a reference for the comparison.
An important additional benefit:
Calculations for the far field can also be carried out from the near field data obtained.
The design of an antenna according to the customer's request - a complex task. As one of the core components of the radar sensor, the antenna plays an important role in the entire system. Here an antenna can do much more than just look "straight ahead": The directional response pattern can be optimally adapted by setting the phases and amplitude assignment of the individual antennae (patches) to the respective requirements. In order to handle the large amount of computing time in this development phase, InnoSenT has high performance multi-processor systems. For the design and simulation of the antennae, 3D and 2.5D software tools are used.
Another milestone in the design of an antenna is the integration into the later working environment. The challenge: The spatial conditions for the installation of the antenna in the vehicle are not always ideal. In this way, bumpers and body parts can affect the performance of the entire system. In order to identify such problems already in advance, vehicle parts and complete body segments are integrated into the simulation. In this way, suitable optimisation measures can be specified early on which, in part, yield significant time and cost benefits in the further development.
To ensure that the simulation corresponds to reality, the antenna must be calibrated. This is done for the far field in a correspondingly dimensioned measurement chamber.
To avoid disruptive reflections, the walls of the measurement chamber are completely covered with absorbent materials. The distance between the antenna and the measurement system is so chosen that only the far range of the antenna is picked up.
At InnoSenT, the customised design of the radar sensor includes not only the design and simulation of the antenna but also the conception of the radio frequency circuit and the necessary DSP-boards.
We also offer embedded software development as one of our services. If necessary, a fully digital interface can be implemented for the sensor. The sensor data obtained can be output either unprocessed or completely evaluated depending on the application.
The electronic and mechanical set-up of the sensor prototypes is done promptly by our in-house production. The final integration of the sensors into the vehicle and the measurements and test drives required for this can also be carried out by the InnoSenT application team if desired.