Fig. 1. Schematic diagram of linear frequency modulated continuous wave radar ranging. (a) Structure of LFMCW radar ranging system; (b) frequency of transmitted and received LFM signal

Fig. 2. Schematic diagram for Photonics-aided generation of quadruple frequency W-band LFM signal. (a)‒(d) Simplified spectra during signal conversion

Fig. 3. Schematic diagram for photonics-aided de-chirping. Insert: simplified spectrum of echo signal

Fig. 4. Experimental setup for photonics-aided quadruple frequency W-band LFM signal sensing and ranging. (a) MZM1 output optical spectrum; (b) FBG output optical spectrum

Fig. 5. De-chirped echo spectrum in 50 cm ranging experiment

Fig. 6. De-chirped echo spectrum in 40 cm ranging experiment