Owner's Manual

4.4 Printed Antenna
The BRD4207A Radio Board includes a printed antenna tuned to have close to 50 Ohm impedance at the 863-930 MHz band, while the
radio board is plugged into the WSTK. The antenna is not connected to the RF output by default; the RF output selector 0 Ohm resistor
should be repositioned from the R2 to the R1 position in order to enable operation with the printed antenna.
The impedance and reflection of the printed antenna is shown in the following figures.
Figure 4.2. Impedance of the Printed Antenna of the BRD4207A
Figure 4.3. Reflection of the Printed Antenna of the BRD4207A
As it can be observed, the impedance is close to 50 Ohm at all of the marked frequencies. The reflection is better than -10 dB.
BRD4207A Reference Manual
RF Section
silabs.com | Building a more connected world. Rev. 1.0 | 9