User's Manual

Table Of Contents
48 novatelwireless.com
Figure 4-3 Example of a GOOD RF Thermal Relief
Antenna And RF Signal Trace
The PCB trace that feeds the RF output port must be designed for a 50 ohm characteristic
impedance, coplanar, or routed into internal layers to keep the top layer continuous around
and underneath the Enabler module. Ample ground vias should be provided around the RF
contacts, the RF trace and launch pad. If possible, keep I/O and power traces away from the
RF port. This includes traces running parallel or orthogonal to it. Thermal relief should not be
used on the antenna output port ground pads. The designer must pay close attention to the
size of the pad and thickness of the dielectric beneath the signal pad and trace. Most PCB
manufacturers can adjust the trace width to maintain 50 ohms impedance if the traces are
identified and instructions are included on the FAB drawing. This service is typically provided
at no or minimal additional cost.
For minimum RF emissions due to the fundamental frequency of operation, the Enabler
module works best with an antenna load that has a VSWR of 1.5:1 or better. The antenna
should not have gain at the harmonic frequencies, otherwise, the conducted harmonics could
get amplified to a point where the product no longer passes type approval. However, for