Study On Method Of Beam Forming Of Ultra Wideband Array

Beamforming is the key technology of array signal processing and intelligent antenna system, widely used in radar, medical, sonar, mobile communication, electronic jamming and reconnaissance, etc. In phased array radar, adjust the launch phase displacement of the beam can be formed need shape, beam direction, and number of the beam. Also, change the phase displacement of each receiving, can receive specified the direction of the echo beam (receive) or multi-channel echo in different direction. Receiving beamforming is usually realized in digital domain receives the echo digitization. Early phased-array radar narrow bandwidth, low range resolution, beamforming method for phase control has been mature, the performance is quite good also. With the improvement of performance requirements of the radar, phased array radar and sonar array bandwidth more and more wide, the range resolution is becoming more and more high, the traditional phased array beamforming method brings aperture transit and frequency dispersion phenomenon. For wideband, ultra wideband phased array radar frequency dispersion and aperture transit problems usually subband processing method are adopted to decrease the aperture transit and frequency dispersion phenomenon. There is no aperture parabolic antenna problem of transit and frequency dispersion. Referencing for the parabolic beamforming principle, this paper, the research uses the time delay instead of phase displacement compensation wave path difference when the phased array technology to realize wideband array without dispersion aperture transit beamforming method. To achieve the accuracy of phased array radar beam forming, precision of time delay to achieve phase-shifting accuracy of phased array radar. The method is suitable for wideband, wideband array sonar array radar and wideband array microphones.In this paper, the main work and contributions are as follows:1. Studied the main problems that exist in the ultra wideband phased array. Paraboloid antenna is introduced, and the difference between the phased array antenna, the broadband phased array antenna aperture generating mechanism of transit and frequency dispersion analysis aperture transit and frequency dispersion effect on the beamforming and signal processing, MATLAB software simulation verification.2. Analysis of the main methods of ultra wideband phased array, the array principle and realization method are put forward. Analyzes the gate delay phased array, optical fiber delay phased array and subband processing of ultra wideband phased array beamforming method, gives the true time delay when the array of basic principle and implementation method of the simulation study. The simulation results show that true time delay method to delay processing of each frequency point, detection effect is very good, subband processing will produce certain error of radar signal processing, eventually detection effect than true time delay method.3. Researched the ultra wideband timed array beamforming method. Two classic DOA estimation method-MUSIC algorithm and ESPRIT algorithm for array of ultra-wideband DOA estimation, mathematical model is established. MATLAB simulation results show that based on the true time delay of DOA estimation of higher precision and resolution performance is good.4. Studied the timed array microphone array. Focuses on the timed array microphone beamforming methods, respectively, the conventional beamforming method, the optimal beamforming method and adaptive beamforming algorithm. On microphone array signal modeling, beamforming using three methods, the MATLAB simulation shows that the conventional beamforming methods cannot effectively suppress noise and interference, even add window also can improve the effect of x or y axes; Adaptive beamforming algorithm has better directivity, but the x axis sidelobe relatively wider; Optimum beamforming algorithm can effectively reduce the signal less susceptible to noise and interference. In this paper, we reseach a new method of ultra wideband array beamforming. Based on the true time delay we put forwad the timed array method of uwb array beamforming. And for ultra wideband timed array radar beamforming and ultra wideband timed array microphones beamforming has carried on the thorough research and simulation. Research results show that the timed array beamforming not have aperture transit and frequency dispersion.