The tasks and requirements of and on glass windows in cars are manifold. In addition to protecting the occupants from sun, wind and weather, they also have a high-frequency technical significance with the integration of antennas. Especially in the field of broadcasting.
AM, FM, DAB and TV, are typical services for antennas installed in front or rear windows or spoilers. Here, “off-the-shelf” antennas cannot be used because each car series has individual body shapes, installation parts and cable runs. Therefore, these antennas are developed in the context of the car. This can be done at the ATC.
Usually, depending on the scope, one or more digital development loops are run through first by means of simulation. The partner for antenna simulation in glass is the company Altair with the programme Feko. This is followed by one or more hardware loops on the far-field measuring range in which various antenna variants can be adapted by rapid prototyping.
At the beginning, all parameters and boundary conditions are discussed in order to create initial design proposals or a start layout. Further development and optimisation take place digitally in the next steps.
Digital development: Simulation
In this case, various iteration steps of the simulation lead to an improvement of antenna performance by a factor of four at 92 MHz and thus to the fulfilment of required limits. More information on the simulation can be found in our knowledge hub.
Prototype of the simulation layout on a rear window
Here, a layout of the simulation was reproduced with copper tape, solder and silver conductive lacquer. After the first glass has been produced according to the simulation layout or an existing glass has been prepared, first measurements can start.
Measurement and hardware tuning
To achieve further improvements in hardware tuning, the layout directly on the glass is gradually adjusted and measured. In illustration 3 you can see the starting layout (green), which shows a clear dip in both vertical and horizontal polarisation. From violet to brown to red measurement, one can see gradual improvements, so that the red line finally shows no dip and at 99 MHz an improvement of up to 9dB has been achieved.
Depending on whether the goal has been achieved, production of the glass can now begin or further development loops can follow.
Especially the flexible scheduling of short-term far-field measurements in our own measurement facility is a great advantage, so that the glass antenna development is significantly simplified and accelerated.
Of course, we can handle all types of glass, lay and remove adhesive beads and transport and store the glass. So we can offer all aspects of glass antenna development.