The Study Of Beamsteering Technology Of Phased Array Laser Radar

Optical Phased Array Radar(OPAR) technology is playing an irreplaceable role in radar control technology due to its advantages of beam agile, multi beam scanning, low coherence and high detection accuracy. While Liquid Crystal Optical Phased Array Radar(LCOPAR), one type of OPAR, become a research hotspot worldwide with the superior characters of small volume, light weight and low driving voltage. The beam-steering device, the core component of Liquid Crystal Optical Phased Array(LCOPA) that guarantee accurate and efficient control of beam deflection, is the key technology of LCOPAR. This paper mainly focuses on the beam control of LCOPAR and the hardware design to realize accurate control of beam deflection. Work as follows:1. Based on blazed grating optical diffraction model and introduction of the microwave phased array radar beam steering theory and the basic principle of liquid crystal phase shifter, analyze the the beam control theory differences between the liquid crystal phase shifter and microwave phased array, further study the beam deflection theory of the Optical Phased Array(OPA) based on optical diffraction model, and analyse various factors on the performance of deflection.2. By analysis the influencing factors(voltage quantization, the edge effect of liquid crystal, the manufacturing error of liquid crystal phase shifter electrode) of beam deflection error, figure out the key performance indicators of the beam-steering device’s scanning unit, then make the driver chip selection of the liquid crystal phase shifter and finally design the module of multi-level pulse width modulated voltage generation which can provide 256 kinds of selectable voltage, of that can efficiently reduce the beam control data; use Butterworth Filter Function to test the fitting cruve of liquid crystal characteristic and make out the beam-steering data method of the scanning unit. Based on works above, complete the overall block diagram of the scanning unit of LCOPA.3. Complete master chip(LCD driver chips, the control program of key FPGA chip) selection, the design of the control program of key FPGA chip using Verilog and the implementation of the data transmission interface, the design and implementation of hardware circuit, the circuit single-level debugging,. Validate the circuit by testing the correlation between output voltage waveform of the liquid crystal driver chip and beam-steering data in storage space. Finally the hardware circuit design of the LCOPA beam-steering device was achieved and verified.4. Complete the joint debugging between the beam-steering device and and the liquid crystal phase shifter, and summarize the debugging experience; design the small angle( ? ? ?3?) deflection experiment of laser with high precision, by comparing the theoretical and experimental results, verify the correctness of the platform. Design the testing experiment of the liquid crystal characteristic curve. And using existing platforms to test liquid crystal characteristic curve, analyze results of the experiments, at the end, obtain the characteristic curve of liquid crystal phase shifter.