An antenna device and an antenna switch circuit are provided. The antenna device comprises a first antenna, an antenna detection circuit, a switch control circuit, and a controller. The first antenna is configured to transmit an RF signal. The antenna detection circuit comprises an inductor configured to detect a second antenna. The switch control circuit is coupled to the antenna detection circuit and configured to generate a first control signal indicative of the presence of the second antenna upon the detection thereof. The controller is coupled to the first antenna, the antenna detection circuit and the switch control circuit, and configured to receive the first control signal and connect to the second antenna when the first control signal indicates the presence of the second antenna.