8.2
RF GND layer
The RF GND layer directly below the top layer is needed for the 50 Ω and 100 waveguide traces. The spacing
between top layer and RF GND layer is relevant for the impedance of the wave-guides. RF currents tend to run
back to its source directly underneath the wave-guides. So it is important that the underlying RF GND layer is
solid and uninterrupted providing a direct path for the RF currents. If a trace on this layer would run underneath a
waveguide trace slicing the ground plane an unwanted slot antenna may have been created. Therefore it is
recommended to avoid routing traces on this layer.
Figure 28.
Layout - RF GND layer
UM2353
RF GND layer
UM2353
-
Rev 2
page 37/48
Содержание ST25RU3993-EVAL
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