tailieunhanh - Behaviour of Electromagnetic Waves in Different Media and Structures Part 16

Tham khảo tài liệu 'behaviour of electromagnetic waves in different media and structures part 16', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 438 Behaviour of Electromagnetic Waves in Different Media and Structures 5. Conclusion In this chapter beamforming of antenna arrays focused in NFZ or IFZ is studied and the new principles of this process are revealed with a purpose to increase the 3-dimensional gain performance of antenna arrays at a wide range of angles and to improve the quality level of this technique for expanding applicability of the focused antenna. The antenna arrays of linear and polygonal structure with different location and types of array elements have been considered in this paper so all tasks of study of FAA radiation pattern synthesis have done in its azimuth plane or in polar coordinates. Expressions of spatial shifts between elements and phase center of arrays where spatial shifts by distance and spatial shifts by angular coordinate are obtained as two separate parts of one equation without any approximation Fresnel or Fraunhofer are introduced. These equations had been obtained first time and they can be useful for FAA with separate phase steering by distance and by angular coordinate synthesis it also helps to reduce the level of computational operations to calculate required phase distribution in array elements. Radiation pattern synthesis and focusing properties of focused arrays are considered in this work which are based on obtained geometrical models of arrays of different structures. Location of array phase center different signal attenuations by propagation from array elements to observation point different angles of radiation from array elements to observation point and array elements radiation patterns dependence on the distance must be taken to account for precise beamforming of arrays focused in NFZ or IFZ. The principles of radiation pattern synthesis of arrays focused in NFZ or IFZ and arrays focused in FFZ are equal. The properties of radiation pattern by distance and angular coordinate are equal too. The main focusing properties of antenna array are based on .