Introduction to Antenna Placement Analyses | ||||
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Several factors can impact the performance of an antenna. The first factor is where you install the antenna (for example, on the exterior hood of a car versus on the car's interior dashboard). The second factor is the shape of the platform beneath the antenna, which might not be flat or symmetrical; for example, an antenna installed on an aircraft fuselage has a cylindrical platform. Finally, there might be other obstructions on the platform (such as tail fins, wings, and other installed antennas) that affect performance.
Antenna placement studies help you find the best position for an antenna on the platform by providing you the results of the installed antenna's performance, which uses the corresponding free-standing antenna simulation as input data.
Free-Standing Antennas Versus Installed Antennas
A free-standing antenna is an antenna in open space or over an infinite ground plane. There are no obstructions except for the cover that surrounds the antenna. Performing a free-standing antenna simulation allows you to verify that the design of the antenna and its cover is optimal for the operating frequency of the antenna.
An installed antenna performs much differently than a free-standing antenna. The geometry of the platform beneath the antenna obstructs the electromagnetic waves in particular directions, limiting the antenna's performance.
The figure below shows two radiation patterns (that is, the directivity) of a simple monopole antenna. The directivity of the free-standing antenna (left) is symmetrical and fairly smooth. The directivity of the antenna installed on an aircraft fuselage (right) is asymmetrical and shows signs of interference from the fuselage geometry.
