Fault Detection Technique for Active Phased Array Antenna Using Current Sensing

This article presents the design and implementation of a built-in fault detection technique for an active phased array antenna. The proposed method employs a current monitoring circuit integrated into the power protection board of the transmit-receive unit (TRU). This circuit consists of a current sense amplifier and an operational amplifier, which detect the drain current of the high-power amplifier within the transmit-receive module (TRM) and compare it against a predefined detection threshold. To facilitate channel control and status reporting of individual TRMs, a built-in test function was implemented in the field-programmable gate array within both the antenna controller and the TRU control board. The test logic monitors the pulse output of the current monitoring circuit and requires four pulse transmissions to confirm a fault. The effectiveness of the proposed technique was evaluated through an initial test using a TRU with an intentionally damaged TRM. Further validation was conducted at both the antenna and radar system levels. The results demonstrated that the antenna can accurately detect and isolate failed TRMs, thereby confirming the reliability of the proposed fault detection method.