Research On Key Techniques For The Improvement Of Antenna Gain Under The Condition Of Limited Radiation Aperture

Since the 19 th century,the technology of wireless information transmission has been developing rapidly;the capacity and efficiency have been continuously improved.As the device for transmitting and receiving electromagnetic waves,antenna plays an important role in the wireless information transmission.Therefore,the high performance property of the antenna has received intensive study.In some particular communication systems,the high gain of the antenna is one key requirement.Unfortunately however,antenna gain usually fails to meet the practical needs due to the limitation of the antenna aperture.This limitation may be caused by the limitation of installation space,or probably due to the special requirements for mechanical scanning.Therefore,it becomes a key technology to improve the antenna gain under the condition of a limited radiation aperture.In this paper,we will study this problem,mainly focusing on the reflector antenna and the array antenna.For reflector antenna,we adopt the methods of designing high efficiency feed and changing the feeding position to improve the gain of the reflector antenna.The study of high-efficiency feeds mainly focuses on three kinds of feeds: ordinary conical horn antenna,dielectric rod antenna and corrugated horn antenna.First,we study the ordinary conical horn,including the beam width,sidelobe level,rotation characteristics of the radiation pattern,and phase center,etc.Next,the characteristics of the dielectric rod antenna are explored.In this section,a method to reduce the side lobe level of the dielectric rod antenna--curvilinear dielectric rod antenna is proposed.A prototype is designed,fabricated and measured.Finally,the characteristics of the axial corrugated horn antenna are studied.For the research of feed position,the feed-forward reflector antenna and the offset reflector antenna are mainly studied,Then,the reflector antenna are simulated and analyzed together with the above three kinds of feeds by the full wave method.Finally,it was verified that high efficiency feed and feed position are important factors affecting the reflector antenna.Finally,based on the factor of avoiding the dissipation of energy of reflector antenna during feeding,the array antenna is used instead of the reflector antenna.And we adopt the methods of different elements and improving the antenna element gain based on design of propagation direction dimension.We study waveguide antenna array,pyramid horn antenna array,dielectric loading horn antenna,microstrip antenna array and Fabry-Perot Cavity antenna array.In this chapter,the element is first analyzed and designed,and the factors affecting the element gain are analyzed.Next the antenna elements are used to form antenna arrays.A variety of array antennas were designed by the choice of different array elements and the design of the direction of the propagation dimension.Finally,the comparative study of these antenna array was carried out under the same conditions.At last,the gain of the array antenna can be improved by different element and optimizing the design in the propagation dimension direction.