Antenna Design - Ublox JODY-W1 Series System Integration Manual

• For PCBs using components bigger than 0402 and dielectric thickness below 200 µm, it is
recommended to add a keep-out (that is, clearance, a void area) on the ground reference layer
below any pin present on the RF transmission lines to reduce parasitic capacitance to ground.
• The transmission lines width and spacing to GND must be uniform and routed as smoothly as
possible: route RF lines in 45 ° angle.
• Add GND stitching vias around transmission lines as shown in
• Include a solid metal connection of the adjacent metal layer on the PCB stack-up to main ground
layer. Include an adequate number of vias on the adjacent metal layer, as shown in
• Route RF transmission lines far from any noise source (as switching supplies and digital lines) and
from any sensitive circuit to avoid crosstalk between RF traces and Hi-impedance or analog
signals.
• Avoid stubs on the transmission lines, any component on the transmission line should be placed
with the connected pin over the trace. Also avoid any unnecessary component on RF traces.
Figure 6: Example of RF trace and ground design
2.2.2

Antenna design

Designers must take care of the antennas from all perspective at the very start of the design phase
when the physical dimensions of the application board are under analysis/decision, since the RF
compliance of the device integrating JODY-W1 module with all the applicable required certification
schemes heavily depends on antennas radiating performance.
• External antennas such as linear monopole:
External antennas basically do not imply physical restriction to the design of the PCB where
o
the module is mounted.
The radiation performance mainly depends on the antennas. It is required to select antennas
o
with optimal radiating performance in the operating bands.
RF cables should be carefully selected with minimum insertion losses. Additional insertion loss
o
will be introduced by low quality or long cable. Large insertion loss reduces radiation
performance and sensitivity.
A high quality 50  coaxial connector provides proper PCB-to-RF-cable transition.
o
UBX-16012621 - R18
C1-Public
JODY-W1 series - System integration manual
Figure
Design-in
6.
Figure 5.
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