Light-control Simulation Study Of Optical Transmission In The Phased Array Radar, Wave Control Technology

In modern wars, in order to improve the anti-jamming ability of phased array antennas, as well as its ability to distinguish and identify the targets, and to solve the problem of radar imaging, the phased array antennas must have big scanning angle (usually + 90o) and the signals of wide instantaneous signal bandwidth. The spread spectrum signal with wider instantaneous bandwidth is required to be adopted because of being menaced by anti-radiation missiles. However, when the phased array antennas are scanning in wide-angle ranges, the instantaneous bandwidth of signals is restricted because of transition time and aperture effect. And then TTD (true time delay) is utilized in optically controlled phased array at sub-array level to replace the phase shifter in general phased array radar system to make time delay compensation at sub-array level, which abates aperture effect considerably and makes the broadband and wide-angle scanning of phased array antennas come true.In the first place, this dissertation introduces the sub-array system of phased array which is based on optical true time delay in detail. Through a great deal of academic deduction and calculation, the flexible and effective techniques of time delay at sub-array level with the function of error correction and a joint beam control method of phase shifters are presented, thereby improving the pointing accuracy of phased array antennas. The joint beam control method of optical TTD 's and phase shifters in phased array antennas presented in this dissertation are proved to be correct by the results of computational simulation experiments. Secondly, on the basis of the phased array system possessing the joint beam control of optical TTD with the function of error correction and phased shifters, this dissertation carries out the simulation analysis and summarization of the changes of parameters, which can influence the performance of phased array system, including the changes of the following factors, such as SNR (Signal Noise Ratio) of input signals, smoothness of range in sub-array pass band of optically controlled phased array, the phase coherence in sub-array pass band of optically controlled phased array, the number of sub-arrays of optically phased array and A/D digits, and so on. Simulating how far the factors influence the systematic performance of optically controlled phased array, especially the influence on the directional patterns and pulse compressed patterns of optically controlled phased array, this dissertation explores the systematic performance of optically controlled phased array further.