Simultaneous Angle-of-Arrival and Frequency Measurement System Based on Microwave Photonics

A simultaneous angle-of-arrival (AOA) and frequency measurement system based on microwave photonics is proposed and experimentally demonstrated. The measurement of the AOA and the frequency is realized based on the simultaneous AOA-to-power and frequency-to-time mapping. Using optical pulses and optical dispersion elements, the frequencies of the received RF signals will map to the time intervals of the output electrical pulses. At the same time, by introducing a DPMZM, the received RF signals with the AOA-dependent phase differences interfere in the optical domain, mapping the AOA-dependent phase difference to the power of the interfered optical sidebands, which further maps to the output electrical pulse amplitudes. By measuring the time intervals and the normalized amplitudes of the output electrical pulses, the AOA and the frequency can be obtained simultaneously. In addition, the measurement of multiple RF signals can be realized due to the independence of the output mapping signals in the time domain for different RF frequencies. A proof-of-concept experiment is carried out. The AOA measurement from −70° to 70° with a measurement error of ±2.5°, and the frequency measurement from 5 to 15 GHz with a measurement error of ±12 MHz are successfully achieved simultaneously. The measurements of single-tone and multiple RF signals are experimentally achieved.