High-locational Medium Wave Navigation Antenna's Investigation And Design

This task comes from an air-force navigation item. It's presented the systematic research in medium wave antenna and the validity check for its electric capability. It contains five parts:It's introduced in the first part that where the task comes from and the brief history and present status of antenna design with the reason why high-locaitional antenna is the best choice.The second part summarizes radiation of basic unit and signal lead according to electromagnetism theory. Then the radiant formula of symmetry unit in the freedom space is gotten. Directional figures of all kinds situation are provided through simulation. The rules scaled the antenna are given including directional figure, directional coefficient, gain coefficient, radiant efficiency, radiant impedance, input impedance and so on.Basic form of antenna is explored in the third part, that is, medium wave umbrella-model antenna. Based on the actual situation, it's proved that high-locational antenna is the best choice. However, this change destroys the original characters of signal. So it's discussed from the antenna with or without load and high located one. Calculation methods of different parameters are given and the change of signal is studied specially.A few of basic ways of electric wave's spread are discussed in part four. At the same time, the influence of the rising antenna is explored from three aspects: the high of interferential building is less than the building which antenna located on, the high is more than the building which antenna located on, but less than the sum of the building and the antenna, the high is more than the sum. And then, electric wave's spread in the freedom space is studied for the convenience of different spread methods' compare. At last, based on the character of antenna, two spread methods are exploded.The last part sums up the paper and explain the innovations of this paper.It's the first time that the electric distributing character is investigated. This is one of the innovations of the paper. The result of it provides the academic guarantee for the rebuilding of antenna and the gist for the enactment of electrical parameters. The fruit of it has been successfully used in some navigation antenna. It has been proved that the theory is basically right through the actual reconnaissance.