User's Guide

BL28EU-RD1 OEM Manual and User Guide

The RF traces from the NAD antenna pins on the main board can be stripline or microstrip. For the

stripline approach, vias should be placed to the NAD EDGE SIDE of the pins as close as possible to the

NAD antenna pads to minimize any impedance discontinuity (see figure 38). For the microstrip approach,

the PCB insertion loss will be less but the short route under the NAD MUST BE TREATED AS STRIPLINE SO

IT WILL BE NARROWER UNDER THE NAD THAN THE MICROSTRIP LINE.

The NAD has ground cleared out under the RF antenna routes as shown below:

Figure 6-2: Antenna Pad Ground Cutout (Top View)

For routing microstrip lines UNDERNEATH the NAD on layer 1, these ground cutouts internal to the

NAD need to be accounted for in the stripline calculation. The internal GND height and dielectric constant

of the NAD board are shown below:

H = 19.3 mils (491 micron)

Dielectric Constant = 4.1

For example, consider the following stackup for a main PCB: