Regardless of the antenna type, some general antenna design guidelines should be followed to reach good antenna performance. More detailed antenna specific requirements are provided in the relevant antenna datasheets.
The dimensions of the ground plane and the placement of the antenna on it may have a significant impact on the performance of the antenna. Also, ground clearance around the antenna and conducting objects near it have an impact on the antenna's performance. For example, mounting screws should not be placed next to the radiator. Placing noisy components next to the antenna should be avoided. In addition to conductors, insulating materials near the antenna impact the antenna performance. Thick, lossy cover on top of the radiator can detune the antenna and increase performance losses significantly.
As the antenna may be sensitive to nearby materials as well as components on the Printed Circuit Board (PCB), antenna tuning should be done on a device in its final assembly when the battery and casing are in place.
Typically, antenna parameters are evaluated in free space that is different from the environment in which it is used. The device can, for example, be held in hand or mounted on a conductive wall. This should be considered when selecting a suitable antenna for the device. Some antenna designs may have worse performance in free space than others, but due to a minor detuning effect of nearby objects, the performance in actual use can be better.