Photonics-Assisted Simultaneous Frequency and Angle-of-Arrival Measurement of Multiple Targets Using Parameter Mapping Method

Abstract

A photonics-assisted simultaneous frequency and angle of arrival (AOA) measurement system based on parameter mapping method is proposed and demonstrated by simulation and experiment. Using optical sideband sweeping and envelope detection, the frequencies of the signals under test (SUT) are mapped to the time domain of the output amplitude of the electrical pulses, and the AOA-dependent phase differences are mapped to the amplitudes of the output electrical pulses. The experimental demonstration shows the frequency measurement capability from 9.4 GHz to 13 GHz, with a absolute measurement error ranging from 1.8 MHz to 5.4 MHz. The frequency range can be adjusted by modifying the bandwidth of the frequency-swept signal or the DC bias voltage. Furthermore, the unambiguous AOA measurement from -90° to 90° is successfully realized simultaneously, and the error of the AOA measurement ranging from -66.44° to 66.44° is confined to within ±1.4º. Due to its robustness and flexibility, this dual-function measurement system can find various applications in future electronic warfare systems.

Keywords: Frequency measurement, microwave photonics, angle of arrival measurement, dual-polarization quadrature phase shift keying modulator