User Manual

APEX/APEX LT
Datasheet (Preliminary Rev 0.2) www.lsr.com Page 9 of 20
9 Antenna
The APEX and APEX LT modules include an integrated PCB trace antenna. An optional
configuration with a MMCX connector is also available. This will enable connector to a 50-
ohm external antenna of the user’s choice.
The integrated PCB antenna topology is an F-antenna. This antenna is used because it is
reasonably compact, has a fairly omni-directional radiation pattern, good efficiency, and is
very simple. An adequate ground plane is necessary to provide good efficiency. The ground
plane of the host board on which the module is mounted increases the effective antenna
ground plane size and improves the antenna performance if done per the guidelines provided
in this datasheet.
The antenna radiation patterns are dependent upon the host board the APEX/APEX LT module
is mounted on. Measured radiation patterns of the module alone are available by contacting
LS Research.
The environment the module is placed in will dictate the range performance. The non-ideal
characteristics of the transmission channel result in the transmitted signal producing reflection,
diffraction, and/or scattering. All of these factors randomly combine to create extremely
complex scenarios.
It is also best to keep some clearance between the antenna and nearby objects. This includes
how the module is mounted in the product enclosure. Unless the items on the following list of
recommendations are met, the radiation pattern can be heavily distorted.
• Never place ground plane or copper trace routing underneath the antenna.
• Never place the antenna very close to metallic objects.
• In the final product, ensure that any wiring or other components do not get too close to
the antenna.
• The antenna will need a reasonable ground plane area on the mother board area to
be efficient.
• Do not use a metallic enclosure or metallized plastic for the antenna.
• Try to keep any plastic enclosure greater than 1 cm from the antenna in any
orientation.