Frequency Diverse Array Using Equivalent Transmit Beamforming: Array Factor for Multiple Receive-Antennas

Spot-like beamforming over range and direction is achievable even in the far field simultaneously, by coupling of the frequency diverse array transmission architecture with a complementary receiver architecture known as equivalent transmit beamforming (ETB). The originally proposed ETB utilizes only a single receive-antenna, but recent enhancements allow for the utilization of multiple receive-antennas. How these additional receive-antennas affect the ETB array factor is analytically derived in this letter, leading to actionable insights for system engineering design.