Studies On Photonic RF Phase Shifter In Optically Controlled Phased Radar

Photonic RF phase shifter is a key component of optical control phased array radar and smart antenna,and their role is to achieve beamforming.Traditional electric phase shifters cannot meet the needs of future phased array radars due to the disadvantages of small bandwidth,high loss,and slow tuning speed.Photonic RF phase shifter is to use the photonics method to realize phase shift of RF signal,and has the advantages of small size,light weight,anti-electromagnetic interference,and large bandwidth.This paper focuses on the research of the techniques of photonic RF phase shift in the field of microwave photonics.(1)This paper first describes the work principle of the optically controlled phased array antenna,and compares and analyzes the various implementation methods of the photonic RF phase shifter.Based on the principle,a photonic RF phase shifter scheme based on polarization control is proposed.The scheme uses a dual-parallel Mach-Zehnder Modulator(DPMZM)to realize the modulation of suppressing carrier single-sideband(CS-SSB),and the phase variation of the radio frequency(RF)signal from 0 to 360-degree is realized by changing the rotation angle of the polarization controller(PC).There is no optical filter in this scheme,therefore it has the advantages of fast tuning of phase and small phase fluctuation of the output signal.(2)At the same time,the paper proposes a scheme of generation of frequencydoubling millimeter-wave with tunable phase based on dual-polarization quadrature phase-shift keying(DP-QPSK)modulator.At the same time,a new frequency-doubled microwave signal processor with full angle phase shift which based on dual-polarization quadrature phase-shift keying(DP-QPSK)modulator is presented and demonstrated in this paper.The DP-QPSK modulator includes two DPMZMs.Under the driving of the RF signal,the top DPMZM produces a negative first-order sideband in the X-polarization state,and the bottom DPMZM produces a positive first-order sideband in the Y-polarization state.Full-phase tuning of RF signals is realized by changing the angle of the PC.The results show that the scheme produces a continuously tunable frequency-doubling RF signal with phase variation from 0 to 360-degree without using an optical filter,and has the advantages of small fluctuation of output signal,fast tuning and large bandwidth.