60-GHz Retrodirective Array System with Efficient Power Management

In this paper, a 60-GHz retrodirective array system is proposed with an efficient power management. The system consists of three sections; a retrodirective array, a local oscillator (LO), and a power management. For efficient battery operation of the retrodirective array, the power management circuit controls the power of the LO by way of a rectenna technology. While there is no interrogating signal, it is initially in a sleeping mode where the system is off with extremely low power. When it is interrogated by an RF signal, the system is awaken and starts consuming full power. The proposed idea is experimentally demonstrated. When the received power density is larger than 0.013 mW/cm ², the system turns on and starts working as a retrodirective array