Application Of The Theory Of Characteristic Modes To Antenna Design

With the development of communication technology,the design of the antenna attracts more and more attention.Antenna play an important role in the performance of communication system.In recent years,the theory of characteristic mode rise again,because it has a clear physical concept,can be intuitive for the designer to provide design guidance.Therefore,it has owned widely application in antenna design.In this paper,the main work is studying the theory of characteristic mode apply in antenna design.It can get the clear physical characteristics of antenna structure by using the theory of characteristic mode.In order to achieve the performance goal of antenna design,we always select the appropriate mode to design antenna which analyzing the resonance characteristics of each characteristic mode.A broadband antenna with a slotted floor was designed by using the characteristic mode theory analysis.Through the analysis of the current distribution of the metal floor as well as resonance and radiation characteristics of the model,selecting the mode with broadband characteristics to stimulate by appropriate feeding.It was well verified that achieve broadband by simulation and physical processing of antenna.A dual-polarized omnidirectional MIMO antenna with conical metal structure is designed and the physical concept is presented directly and clearly by the theory of characteristic mode.Selecting the appropriate feeding position and designing the suitable feed network to excite the horizontal current and vertical current in the structure as the operating mode and the dual-polarization antenna is realized on the single structure.The character of dual-polarization omni-directional antenna is verified by simulation and physical test.Compared with other dual polarized antennas,the antenna has a good isolation performance.Using the theory of characteristic mode to get the character of the circular polarization antenna metal floor grooving.The characteristics of modes that are expected to excite by coupling feed,in order to reach the expected target design of circular polarization antenna.At same time,we know the working principle of circular polarization antenna.