Rf Circuit - Espressif Systems ESP32 Hardware Design Manuallines

Chapter 3. Schematic Checklist
3.5 RF

3.5.1 RF Circuit

ESP32's RF circuit is mainly composed of three parts, the RF traces on the PCB board, the chip matching circuit,
the antenna and the antenna matching circuit. Each part should meet the following requirements:
• For the RF traces on the PCB board, 50 Ω impedance control is required.
• For the chip matching circuit, it must be placed close to the chip. A CLC structure is preferred.
– The CLC structure is mainly used to adjust the impedance point and suppress harmonics, and
a set of LC can be added if space permits.
– The RF matching circuit is shown in Figure
• For the antenna and the antenna matching circuit, to ensure radiation performance, the antenna' s characteristic
impedance must be around 50 Ω. Adding a CLC matching circuit near the antenna is recommended to adjust
the antenna. However, if the available space is limited and the antenna impedance point can be guaranteed to
be 50 Ω by simulation, then there is no need to add a matching circuit near the antenna.
Espressif Systems
Fig. 11: ESP32 Schematic for External Oscillator
Fig. 12: ESP32 Schematic for RF Matching
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ESP32 Schematic for RF Matching.
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