Espressif Systems ESP32-H2 Series Hardware Design Manuallines page 24

3 PCB Layout Design
• The RF trace should have consistent width and not branch out. It should be as short as possible with
dense ground vias around for inteference shielding.
• The RF trace should be routed on the outer layer without vias, i.e., should not cross layers. The RF trace
should be routed at a 135° angle, or with circular arcs if trace bends are required.
• Please add a stub to ground at the ground pad of the first matching capacitor to suppress second
harmonics. It is preferable to keep the stub length 15 mil, and determine the stub width according to the
PCB stack-up, so that the characteristic impedance of the stub is 100 Ω ± 10%. In addition, please
connect the stub via to the third layer, and maintain a keep-out area on the first and second layers. The
trace highlighted in Figure
• The ground plane on the adjacent layer needs to be complete. Do not route any traces under the RF trace
whenever possible.
• There should be no high-frequency signal traces routed close to the RF trace. The RF antenna should be
placed away from high-frequency components, such as crystals, DDR, high-frequency clocks, etc. In
addition, the USB port, USB-to-serial chip, UART signal lines (including traces, vias, test points, header
pins, etc.) must be as far away from the antenna as possible. The UART signal line should be surrounded
by ground copper and ground vias.
Espressif Systems
Figure 18: ESP32-H2 PCB Stack up Design
19 is the stub. Note that a stub is not required for package types above 0201.
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ESP32-H2 Series Hardware Design Guidelines v0.5