A new kind of smart antenna capable of automatically switching its main beam to track a moving target is presented. The antenna, which is suitable for mobile communication in long straight spaces, such as railways or highways, integrates a sensing element, signal processing element, and radiating element. The sensing element works based on a frequency-modulated continuous wave and delivers a beat frequency signal containing environmental information to the signal processing element, which is used to control the excitation of the radiating element. To verify the efficiency of the proposed antenna, a prototype is fabricated and implemented in a real corridor scenario. Furthermore, the error vector magnitude (EVM) along the test path is investigated to evaluate the system performance when using the proposed antenna. The results show that this kind of smart antenna is capable of improving mobile communication quality and decreasing energy consumption. Therefore, it is a promising candidate for mobile communication.