| The design and the calibration of the transmit array in a type of ground wave radar are discussed in this thesis.The design and simulation of the transmit antenna is treated in the second chapter. First, the characteristics of the transmit antenna are introduced briefly. Then the Yagi-Uda antenna utilized in our experimental system is analyzed and simulated using the software Super NEC, and the real data results are shown. Finally, for the radar to work at a wide frequency band, a scheme of log-periodic antenna is presented. The simulation results show that the log-periodic antenna designed could satisfy the requirement.The error estimation and calibration of the transmit array is discussed in the third chapter. The mathematical error model for the transmit array is described briefly at first. Then the algorithms where the direct wave is used for calibration are proposed. Finally, a beam forming formula based on linearly constrained minimum variance is derived in order to calibrate the transmit array at the receiving station. Thus, the error calibration of the transmit array can be performed when the transmitted pulses synthesis is carried out. The simulation results show the validity of the algorithms. |
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