| The technology of Radar Over Fiber has been a hot research area in radar communication and optical fiber communication. Using modern advanced optic-fiber communication technology and high phase stability optical fiber transmission line, the main purpose of this paper is to design a 0.5~10GHz optic-electronic conversion and transmission system applied in radar destination RCS test and simulation system, and to verify by theoretical analysis and experiments that the system can reach the established technical target.According to the requirement of the system, in the process of microwave signal transmission, the optical-fiber transmission line could be arbitrarily moved, stretched and bent, but the phase difference between the input microwave signal and the output one maintains steady. Therein lies the difficulty of the system: to design a high phase stability optical fiber transmission line. Firstly, how the ess-strains influence the phase stability of microwave signal in fiber is analyzed; and then put forward a PVC spiral-shaped optical-fiber transmission line through the comparison of the prior optical-fiber transmission line fabric. Using this type of optical-fiber transmission line, the phase of a 10GHz microwave signal after 70 meters transmission varies within 1 degree, in the process of arbitrarily movements of the transmission line.Besides, it introcuces the working principles of each device of the system (including LD, LiNbO3 modulator, fiber, PIN and microwave amplifier), and analyzes how the device influences the microwave signal's phase.Devices are selected based on the former analysis and combined with the technical specification. Finally, system experiment is conducted, and the experimental results basically meet the requirement.The other main purpose of this paper is to design a ultra-wideband microwave amplifier. It firstly introduces the theory of stability, noise, gain and VSWR which should be focused on in amplifier design; then it presents several design methods of wideband amplifier, and emphasizes on feedback amplifier. At last, in accordance with the specification, it discloses detailed design steps and the corresponding ADS simulation results. |
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