interference is present. If this fails to resolve the issue, please contact Linx
technical support.
About Antennas
The choice of antennas is one of the most critical and often overlooked
design considerations. The range, performance, and legality of an RF link
are critically dependent upon the type of antenna employed. Linx offers
a variety of antenna styles that you may wish to consider for your design.
Included with your kit is a Linx CW Series connectorized whip antenna
that should be connected prior to using the kit. Despite the fact that the
antenna is not centered on the board’s ground plane, it exhibits a VSWR of
<1.7 and suitably demonstrates the module’s best practical performance.
Using the Boards as a Design Reference
The basic evaluation boards included in this kit are very simple, yet they
illustrate some important techniques that you may wish to incorporate into
your own board layout. You will observe that the LC mounting pads extend
slightly past the edge of the part. This eases hand assembly and allows for
better heat conduction under the part if rework is necessary. Next, observe
the use of a full ground plane fill on the lower side of the board. This ground
plane serves three important purposes:
First, since a quarter-wave antenna is employed, the ground plane is
critical to serve as a counterpoise (you may wish to read Application Note
AN-00500 Antennas: Design, Application, and Performance for additional
details on how a ground plane affects antenna function).
Second, a ground plane will suppress the transfer of noise between stages
of a product, as well as unintentional radiation of noise into free space.
Third, a ground plane allows for the implementation of a microstrip feed
to the antenna. The term microstrip refers to a PCB trace running over
a ground plane that is designed to serve as a 50-ohm transmission line
between the module and the antenna. A microstrip is implemented on this
evaluation board. If you are unfamiliar with microstrip calculations, you may
wish to refer to the LC Series data guides or the calculator available on our
website.
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