Integration Manual

ANNA-B4 series - System integration manual
UBX-21000517 - R03 Appendix Page 70 of 76
C1-Public
Figure 34 shows the GND layer of the external antenna reference design.
Figure 34: GND layer reference design for external antenna
The 50 Ω coplanar microstrip dimensions used in the reference design are described in Figure 35 and
Table 24. The GND plane beneath the RF trace must be filled.
Figure 35: Coplanar microstrip dimension specification
Item
Value
T
Solder mask: 20 +/- 10 µm
Copper film and plating/surface coating: 35 +/- 15 µm

r
3.77 +/- 0.5
Table 24: Coplanar micro-strip specification
B.4 Examples of application ground plane miniaturizations
As the antenna characteristics are dependent on the dimensions of the PCB, especicially for small-
sized PCBs, the physical size of the PCB must be carefully considered to ensure a sufficient antenna
performance for each application.
The following examples show the achievable antenna performance for reduced PCB sizes. The
antenna is ideally characterized with a full 3D test in an RF diagnostic chamber. If this is not
feasible, an in-door test of the application in a multipath faded environment is often sufficient to
confirm the performance and behavior of the product. Optional range measurements can also be
taken with an open-field, line of sight, to confirm the antenna gain and efficiency.
In most cases, a spheric 3D antenna radiation pattern is ideal for products operating in
environments where multipath fading occurs.