Adaptive antenna system by ESP32-PICO-D4 and its application to web radio system

摘要

Graphical abstract An example of actual antenna selecting process. Figures (a), (b) and (c) are showing RSSI of a given access point defined by SSID for antenna number “n”, and (d) determines the best antenna for communication, and (e) shows the web-radio process starting. Display Omitted Abstract Adaptive antenna technique has an important role in the IoT environment in order to establish reliable and stable wireless communication in high congestion situation. Even if knowing antenna characteristics in advance, electromagnetic wave propagation in non-line-of-sight environment is very complex and unpredictable, therefore, the adjustment the antenna radiation for the optimum signal reception is important for the better wireless link. This article presents a simple but effective adaptive antenna system for Wi-Fi utilizing the function of a highly integrated component, ESP32-PICO-D4. This chip is a system-in-chip containing all components for Wi-Fi and Bluetooth application except for antenna. Together with SP3T RF switch and dielectric antennas and high-resolution audio DAC, completed web-radio system is made in the size of 50?×?50?mm.