A Research Of The Principle And Methods Of The Parallel Multi-beam Antenna Array

Multi-beam technology which can form multiple received or transmitted beams sharing the same antenna aperture, and the direction of the forming beams can be scanned rapidly, the shape of the forming beams can be changed flexibly, is an important branch of beamforming. It has been attracting the attention of the international scholars since it was proposed in the 1960 s. After more than 50 years of development, Multi-beam technology has achieved fruitful research results, and played an important role in practical application. In modern times, Multi-beam technology has been widely used in radar, sonar, electronic countermeasure, and communication systems. The main research content of the dissertation is the theory and algorithms of Multi-beam technology. The main works of the dissertation are as follows:1. Array signal models are introduced based on line array and square array respectively. The dissertation also expounds the basic principle of the receiving and transmitting multi-beams by the array antenna.2. The dissertation introduces several common multi-beam forming algorithms detailed, including separate weighted multi-beam former, FFT multi-beam former and multi-linearly constraint minimum variance multi-beam former and analyzes the characteristics of three algorithms forming the multi-beam. The application of a new orthogonal of signal subspace estimation on the orthogonal projection algorithm to launch multi-beam is studied.3. The dissertation studies array multi-beamforming on the condition of uniform contiguous subarrays, uniform contiguous subarrays and non-uniform subarrays since the number of the antennas of the phased array radar is increasing fast in modern times.4. In modern communication systems, the desired signals received by the array are coherent signals from different directions for the multipath effect. So the dissertation studies the multi-beam former that can receive the coherent signals effectively and proposes two new beamfomers. one need to know the angle range of the coherent signals, the other is a blind beamformer, which can construct the data matrix of the coherent signals based on the fact that the covariance matrix of the independent signals and the noise is Teoplitz matrix, while covariance matrix of coherent signals isn’t the Teoplitz matrix first; then the weight vector of the proposed beamformer can be obtained based on the eigenvalue decomposition of the covariance matrix of the coherent signals which is obtained by the first step.