Research On Pattern Reconfigurable Antenna Elements Applied To Phased Array

In recent years,with the advance of information age,modern wireless communication technology develops rapidly,the requirements of antenna also tend to be intelligent,integrated,multi-function and other aspects of development.The current complex electromagnetic environment has put forward higher and higher requirements for the comprehensive performance of modern electronic information systems.Usually,a variety of radio subsystems need to be integrated on the same platform,such as early warning radar,fire control radar,identification friend or foe,etc.If each system adopts a phased array working in different frequency bands,different polarizations,and different radiation states to receive and transmit electromagnetic signals,It will lead to high cost,large weight,large scattered cross-sectional area,strong electromagnetic interference between systems and other problems.Therefore,the design of phased array antenna with strong adaptive ability has become the focus of current research.Among them,the directional pattern reconfigurable antenna with various radiation functions has become the focus of attention.The directional pattern reconfigurable antenna can enlarge the beam radiation range of a single antenna,and the signal of a wider area can be covered by a small number of antennas.Moreover,the phased array antenna using the directional pattern reconfigurable antenna unit can improve the beam flexibility,dynamically adjust the radiation gain,reduce the beam sidelobe and have strong adaptive ability.It can meet the requirements of intelligent and multi-function antenna in current wireless communication system.Therefore,the characteristics of directional graph reconfigurable antenna and its array are studied in this thesis.The details are as follows:（1）.Reconfigurable pattern antenna based on T-shaped guide slotFirstly,based on the combined application of TM₁₀ mode and TM₁₂ mode,a broadband microstrip antenna covering 5G-N78 frequency band（3.3GHz-3.8GHz）is designed.Then,by introducing a T-shaped channel in the antenna floor and loading a PIN diode at the end of the channel for pattern reconstruction,a pattern reconfigurable microstrip patch antenna with three different beam directions is proposed.The main beam directions of the antenna can be switched freely at+32°,0°and-32°.The antenna is simple in structure,small in size,low in profile and low in production cost,which can be used in 5G applications.（2）.Reconfigurable pattern antenna based on open resonant ringFirstly,a miniaturized microstrip patch antenna is designed based on capacitive loading technology.Then,by loading a parasitic microstrip ring on the periphery of the radiating patch,and cutting slots in the center of both ends of plane H to load the opening direction of the resonant ring controlled by a PIN diode,the pattern reconstruction of the microstrip patch antenna was realized.A pattern reconstruction microstrip patch antenna with three different beam directions was proposed.The main direction of the antenna beam can be switched freely at+32°、0°and-33°with small gain variation.（3）.The design of array antenna based on reconfigurable antenna elementFirstly,the product principle of directional pattern in array antenna is analyzed,and the difference between the directional pattern reconfigurable antenna element in array and traditional antenna element is introduced theoretically.Then,a miniaturized directional pattern reconfigurable antenna element for array applications is proposed,and the mutual coupling problem of unit antennas in array is analyzed.Finally,the performance difference between the array composed of directional pattern reconfigurable antenna elements and the array composed of common antennas is compared,and the advantages of directional pattern reconfigurable antenna are proved.