Compact triple-function microwave photonic signal-processing unit

A compact microwave photonic signal-processing unit for frequency diverse array (FDA) radar transmitters is proposed and numerically demonstrated. The unit is mainly implemented using a single dual-polarization dual-parallel Mach–Zehnder modulator (MZM), without optical filters, polarization controllers, polarizers, or additional phase modulators. In the proposed structure, the frequency shift is determined by the frequency of the sawtooth waveform, whereas the phase and amplitude of the frequency-shifted microwave signal are controlled by the DC bias voltages applied to the sub-MZMs and main-MZMs, respectively. Numerical simulations demonstrate frequency shifting from −12 to 12 MHz for single-tone signals, whereas broadband LFM processing is verified for frequency shifts of 4 and 12 MHz. Continuous 360 deg phase tuning and an amplitude-control span of ∼60 dB are also demonstrated. Practical nonidealities are further assessed through individual sensitivity analyses and a combined-tolerance Monte Carlo model, which yields a median electrical spurious suppression ratio of 32.0 dB under the specified tolerances. Calculated link metrics further quantify the noise-dependent usable amplitude-control range. These numerical results suggest that the proposed structure can serve as a compact and electrically reconfigurable building block for FDA radar transmitters.