| Noise and interference are inevitable in radar channel. They enter the received system through side or main beams, and reduce the system's receiving signal-to-noise ratio (SNR). With the development of the technology of antenna, adaptive antenna emerges as time requires. Adaptive antenna can react to interfering signal automatically, form the beam zero points at interference and keep the signal receptions in right directions.Linear array and circular array are the two commonest types in adaptive antenna arrays. Linear array can only provide an azimuth scan ranging from 0 to 180 degree, while circular array from 0 to 360. By means of recurring moving array excitation, circular array controls the beams'orientation simply and neatly, creating a perfect pattern in azimuth and an ideal pattern in pitch. This thesis analyzes circle array's performance and employs different arithmetic accordingly; transforms circle arrays to line arrays by mode transform; analyzes the space geometry antenna's pattern function. The main tasks finished in this paper include:1. This thesis deduces circular arrays and line arrays pattern's synthesis function and compares their performance and characteristics according to simulation results. Also the influence of amplitude and phase quantification is analyzed in array signal.2. SMI algorithm is analyzed and researched when being applied in array signal processing. Characteristic comparisons between SMI algorithm and GS algorithm are compared according to the simulation results.3. Estimation about the number of the disturbances is done by means of Gerschgorin disk theorem, which is also employed to reduce the G-S algorithm false dismissal possibility basing on the former estimation results.4. Problem of circular array's high side-lobe (relative to main-lobe) and the lower depth of zeros is resolved using mode space transform, which changing uniform... |
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