Photonic generation approach of linearly chirped microwave waveform(LCMW) with tunable frequency and bandwidth multiplication factor(FBMF) based on parallel Mach-Zehnder modulator(MZM) is proposed. Theoretical analysis show that LCMW with FBMF of 4, 8 and 12 can be obtained by properly adjusting the amplitude of linearly chirped microwave drive signal and direct current(DC) drive signal. The scheme greatly reduce the frequency and bandwidth of electrical linearly chirped microwave drive signal. Due to no filter is employed, so the generation LCMW has a large frequency and bandwidth tunable range. Furthermore, the feasibility of the approach is demonstrated by the simulation based on OptiSystem platform.
A Ka-band microwave photonic imaging radar demonstrator with 10.02 GHz-bandwidth is proposed and experimentally demonstrated. Continuous linear frequency waveform is optically generated in the transmitter and processed in the receiver. The range resolution of the demonstrator is tested to be 1.68 cm. Out-field tests while demonstrator works at inverse synthetic aperture radar (ISAR) and synthetic aperture radar (SAR) mode are carried out to image different targets.