diff --git a/docs/en/api-guides/wifi.rst b/docs/en/api-guides/wifi.rst
index 711cc4c687..d66c8fe3d1 100644
--- a/docs/en/api-guides/wifi.rst
+++ b/docs/en/api-guides/wifi.rst
@@ -1662,7 +1662,9 @@ The Wi-Fi multiple antennas selecting can be depicted as following picture::
 
 Up to four GPIOs are connected to the four active high antenna_select pins. {IDF_TARGET_NAME} can select the antenna by control the GPIO[0:3]. The API :cpp:func:`esp_wifi_set_ant_gpio()` is used to configure which GPIOs are connected to antenna_selects. If GPIO[x] is connected to antenna_select[x], then gpio_config->gpio_cfg[x].gpio_select should be set to 1 and gpio_config->gpio_cfg[x].gpio_num should be provided.
 
-Although up to sixteen anteenas are supported, only one or two antennas can be simultaneously enabled for RX/TX. The API :cpp:func:`esp_wifi_set_ant()` is used to configure which antennas are enabled.
+For the specific implementation of the antenna switch, there may be illegal values in `antenna_select[0:3]`. It means that {IDF_TARGET_NAME} may support less than sixteen antennas through the switch. For example, ESP32-WROOM-DA which uses RTC6603SP as the antenna switch, supports two antennas. Two GPIOs are connected to two active high antenna selection inputs. The value '0b01' means the antenna 0 is selected, the value '0b10' means the antenna 1 is selected. Values '0b00' and '0b11' are illegal.
+
+Although up to sixteen antennas are supported, only one or two antennas can be simultaneously enabled for RX/TX. The API :cpp:func:`esp_wifi_set_ant()` is used to configure which antennas are enabled.
 
 The enabled antennas selecting algorithm is also configured by :cpp:func:`esp_wifi_set_ant()`. The RX/TX antenna mode can be WIFI_ANT_MODE_ANT0, WIFI_ANT_MODE_ANT1 or WIFI_ANT_MODE_AUTO. If the antenna mode is WIFI_ANT_MODE_ANT0, the enabled antenna 0 is selected for RX/TX data. If the antenna mode is WIFI_ANT_MODE_ANT1, the enabled antenna 1 is selected for RX/TX data. Otherwise, WiFi automatically selects the antenna that has better signal from the enabled antennas.