Transmit-Receive Module Diagnostic of Active Phased Array Antenna Using Side-Lobe Blanking Channel

Area of Science:

• Radar Systems Engineering
• Antenna Technology
• Aerospace Electronics

Background:

• Airborne active phased array antennas (APAAs) require robust diagnostic methods for transmit-receive modules (TRMs).
• Existing diagnostic solutions face spatial, cost, and time constraints in airborne radar systems.
• The peripheral probe method offers a potential solution but requires careful implementation.

Purpose of the Study:

• To develop and validate an efficient diagnostic method for TRMs in APAAs.
• To leverage existing antenna channels to minimize system modifications.
• To establish a reliable fault detection threshold for TRMs.

Main Methods:

• Implemented a diagnostic method using the side-lobe blanking (SLB) channel as a peripheral probe.
• Conducted an APAA-level test in a movable anechoic chamber to determine fault detection thresholds and prevent TRM saturation.
• Performed signal path budget analysis to determine optimal input attenuation levels.
• Developed simple detection logic and control timing for the radar processor.

Main Results:

• The coupling level between the SLB antenna and TRM was optimized between -70 dB and -20 dB.
• The received signal power was estimated between -40 dBm and -20 dBm, leading to a fault detection threshold of -50 dBm.
• Validation tests in an anechoic chamber, rooflab, and on an actual fighter aircraft confirmed the method's effectiveness.

Conclusions:

• The proposed diagnostic method effectively identifies TRM faults in APAAs using the SLB channel.
• The approach successfully addresses spatial and cost constraints in airborne radar systems.
• The validated method provides a reliable and efficient solution for airborne radar diagnostics.