ESP32 is already integrated antenna and RF balun, power amplifier, low-noise amplifiers, filters, and power management module. The entire solution takes up the least amount of printed circuit board area. This board is used with 2.4 GHz dual-mode Wi-Fi and Bluetooth chips by TSMC 40nm low power technology, power and RF properties best, which is safe, reliable, and scalable to a variety of applications.
Useful links:
1. ESP32 datasheet: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf
2. ESP 32 Technical Reference Manual: https://espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf
3. ESP 32 Wiki: https://en.wikipedia.org/wiki/ESP32