ИСТИНА

Reconstruction of an object using the holography and the amplitude-phase distribution measurement methods realized with microwave photonics is considered. To form a hologram or measure the amplitude-phase distribution, the signal from each element of the radar phased antenna array (PAA) is fed for modulation to the input port of one arm of a dual-parallel Mach-Zehnder modulator, and a reference microwave signal is fed to the input port of the second arm. At the output of the modulator, the sum of two optical fields is formed, and each is modulated by its own signal. As a result, the signal after photodetector is determined by the interference of the echo wave field at the location of the PAA element and the reference wave, i.e. it is an element of the radio hologram. By measuring such elements of the radio hologram over the entire aperture of the PAA and digitizing them, it is possible to obtain an array of data describing the complete radio hologram. The radio image of an object can be synthesized after performing a fast Fourier transform. Similarly, the amplitude distribution of the echo signal can be obtained using an additional intensity measurement at the output of the low-noise amplifier after each PAA element. Formation of the corresponding amplitude-phase distribution in the optical region of the spectrum is also considered. Measurements of the phase differences and the intensities for the reference and reflected signals in the X range confirmed the effectiveness of the developed technique.