Investigations On Broadband High Efficiency Cavity-Backed Antennas

With the rapid development of the satellite communications,radar,and remote sensing,the antenna which is an important component of electromagnetic wave transmission and reception play an important role in systems.The planar broadband antenna has the advantages of low profile and easy integration.In terms of performance,the working frequency bandwidth is wide,which can meet the needs of different frequency bands,and achieves a variety of different purposes.Therefore,planar broadband antennas have received extensive attention and application in recent years.In this paper,the different planar broadband antennas based on cavity-backed are studied.The low profile,wideband,high gain and high efficiency of the antennas are achieved through formal innovation,structural optimization,and cavity-backed loading.The main work of this paper is as follows:1.According to using different methods of the impedance bandwidth expansion,a planar wideband slot antenna is designed.In the design of the proposed antenna,the weight of the antenna is reduced by using a reflecting surface instead of the cavity-backed.The broadband characteristics of the antenna are realized by applying the form of wide slot and loading slots.By introducing differential feeding,the antenna can maintain a stable radiation pattern within wide frequency band.Moreover,a hierarchical feeding network is proposed,which is used to design a 4×4 slot array antenna.2.In view of the high profile and low efficiency of the traditional unidirectional radiating slot antenna,a broadband,low profile and high efficiency cavity-backed slot antenna is design using the high-order resonant mode(TE₄₄₀ mode)of the substrate integrated waveguide cavity.The antenna is designed by using the TE₄₄₀ mode,which reduces the use of the metal column in the feeding network.The metal loss and manufacturing error are decreased,and the gain and aperture efficiency of the array antenna are effectively improved.3.Due to the low efficiency or narrow bandwidth could be caused in the two antenna types proposed above,in order to ensure high efficiency and wider impedance bandwidth,the magnetoelectric dipole antenna is studied in this paper.By modifying the structure of the antenna,a broadband high efficiency cavity-backed magnetoelectric dipole antenna array is designed and implemented.In the design process,the impedance bandwidth of the antenna is increased by utilizing a bow-shaped dipole patch and loading opening slot.The gain of the antenna is increased by introducing a substrate integrated waveguide cavity-backed without increasing the size of the antenna elements.Then based on the antenna element,a 4×4 broadband high efficiency magneto-electric dipole array antenna is designed and implemented by applying the substrate integrated waveguide feeding network.