Research Of A High-gain Antenna And The Beam Control

With the increasing demand for data traffic,the desire of building "Internet of Everything" has also been unstoppable.However,the number of 3G and 4G macro base stations currently deployed cannot meet these requirements.It is not only make the block more crowded,but also add a lot of construction costs if we build more macro base stations in city downtown.Using small cells to complete the wireless connection between the mobile terminal and the base station is the best solution in the face of aforementioned contradiction.Small cells are placed on the existing buildings to realize the wireless backhauling between base stations,the mobile terminal and the base station,which not only can reasonably utilize the space,but also can satisfy the demand for data traffic.The backhauling antenna,which is installed in the small cell,has two characteristics of moderately high gain and beam-deflection function when we use the small cell in this scenario.Therefore,it is of great significance that studying the high-gain antenna and studying the beam control.This paper focuses on the feasibility study of the beam deflection of short backfire antenna(SBA)with a simple structure,low cost and moderately high gain,and the potential value of beam-deflection short backfire antenna(BD-SBA)used in the wireless backhauling of 5G.In short,the main content of the thesis can be summarized as follows:1.Analysis of the working principle of SBA and explanation of the basic theory of the BD-SBA implementing beam deflection.The working principle of SBA is analyzed by "Image method" and "Equivalent reflector method".On the basis of "Equivalent reflector method",the feasibility of SBA implements beam deflection is discussed.It is demonstrated that the two reflected waves which are reflected by the main reflector are the main components for the far radiation of the SBA.The method demonstrated that SBA can realize beam deflection by changing the phase of reflected waves.2.Design of a BD-SBA with a deflection plate,which controls the beam deflection by tilting the tilt angle of the deflection plate.The influence of each parameter on the antenna performance was analyzed by using the electromagnetic simulation software Ansoft HFSS.An X-band BD-SBA with a beam pointing of 12° is fabricated and tested.The measured and simulated results are in good agreement.A gain of 14.3 dBi and a sidelobe level of-20.6 dB are realized at 10 GHz.3.Design of a BD-SBA basing on Artificial magnetic conductor(AMC)technology.The AMC is a high-impedance surface which exhibits a unique electromagnetic characteristic,namely an in-phase reflection coefficient for incident plane waves.An inhomogeneous AMC surface is designed as the main reflector of SBA.The reflected phase and current distribution of the inhomogeneous AMC surface elements are analyzed in order to change the phase of reflected wave by adjusting the size of AMC elements.The BD-SBA with inhomogeneous AMC has beam-deflection capability and has a lower profile than the BD-SBA with a deflection plate.