Research On System Theories And Key Techniques Of Optically Controlled Phased Array Radar

Restricted by the aperture transition-time of array, the conventional phased array radar only operates under the relatively narrow-band signals. Although it has many technical and tactical advantages, it cannot be applied to the complex conditions and the domains requiring high-performance. Optically controlled phased array radar (OCPAR) with applied optical true time delay (OTTD) and optical beamforming-network can be used to improve the instantaneous bandwidth of the conventional phased array. OCPAR can work under the wideband or ultra-wide band (UWB) conditions, miniaturize phased array radars, and provide with the ability of anti-electromagnetic-interference. It possesses the performances to meet the all-sided and high-performance needs for radars in the modern war. OCPAR, therefore, has become an important trend in the development of phased array radar.OTTD technology has been mainly used to improve the numerous performance indexes of phased array radars. OCPAR is an interdisciplinary approach involving electronics and optics, combining component techniques with system performance analyses. Because photoelectron technology is adopted, radar or microwave signal must be first transformed into optical carrier signal by a laser or optical modulator. The transformed signal is transmitted in fiber-optic, delayed by OTTD units, and then transformed reversely into electronic signal by an optical detector. This signal is further used to regenerate the original radar signal. During the transmission and distribution of radar signals, the noises and interferences from optic-link may distort the signal to affect the performances and pattern of system as well as the array's signal processing.For the first time, the system theories and the important key techniques were thoroughly investigated based on the results from an experimental OCPAR. The main innovative results in the dissertation are as follows:(1) The vector model of OCPAR for numerical simulation was built, the factors that influence the instantaneous bandwidth were theoretically analyzed, and the relationship between the mainlobe-widening and the bandwidth of signal was studied.