
Hardware
Design notes
XBee/XBee-PRO® S2C ZigBee® RF Module
32
Through-hole keepout area
Notes
1. We recommend non-metal enclosures. For metal enclosures, use an external antenna.
2. Keep metal chassis or mounting structures in the keepout area at least 2.54 cm (1 in) from the
antenna.
3. Maximize the distance between the antenna and metal objects that might be mounted in the
keepout area.
4. These keepout area guidelines do not apply for wire whip antennas or external RF connectors.
Wire whip antennas radiate best over the center of a ground plane.
Design notes for SMT RF pad devices
The RF pad is a soldered antenna connection. The RF signal travels from pin 36 on the device to the
antenna through an RF trace transmission line on the PCB. Any additional components between the
device and antenna violates modular certification. The controlled impedance for the RF trace is 50 Ω.
We recommend using a microstrip trace, although you can also use a coplanar waveguide if you need
more isolation. Microstrip generally requires less area on the PCB than coplanar waveguide. We do not