Windscreen Antennas

Windscreen antenna integrated in concept vehicle

Radiation pattern and current distribution of windscreen antenna

The proliferation of communication devices that are required in modern automobiles, require manufacturers to include more and more antennas into vehicles.  Requirements include FM/AM antennas, TV antennas, etc.  Ideally, antennas should be integrated in unobtrusive ways. 

A prominent modern development is to include antennas into the windscreens of a vehicle.  These windscreens include multiple layers of glass and wiring that form the antenna.  As with other antenna designs, engineers require the ability to simulate new designs to evaluate many antenna operating characteristics, such as efficiency, impedance bandwidth and far-field radiation pattern.

To address this need, FEKO includes a solution method based on the MoM that can be used for rigorous analysis of windscreen antennas.  The method meshes only the metallic antenna elements, so the resource requirements that are devoted to modelling of the dielectric layers of the glass is almost negligible.  Features of the method include:

• Boundaries of the dielectric interfaces between different layers of glass are accurately taken into account
  
• Coupling between closely spaced antenna elements are taken into account
• Finite size glass antennas can be integrated into a full car model
• Curvature and rotation of the window is considered
  

In the example below, a FEKO model of a car with integrated windscreen antenna is shown with a comparison of simulated and measured reflection coefficient data. These results show that FEKO can predict the performance of such antennas very accurately.

 

Detail model of windscreen antenna		Windscreen antenna reflection coefficient