Windscreen Antennas

Windscreen antenna radiation pattern
Full model of car
Detail of windscreen antenna
Windscreen antenna reflection coefficient

The proliferation of communication devices that are required in modern automobiles, require automobile designers to include more and more antennas into their vehicle designs.  Requirements include FM/AM antennas, TV antennas, etc.  Aesthetically speaking, this is a problem that can only be overcome by including such antennas into vehicle designs in unobtrusive ways.  A prominent modern development is to include these 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, including:

• Efficiency
• Impedance bandwidth
• Far-field radiation characteristics

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 accounted for.
• 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.

On the right, a FEKO model of a car with integrated windscreen antenna is show. At the bottom, simulated and measured reflection coefficient data is compared. These results show that FEKO can predict the performance of such antennas very accurately.