| With the development of the times,new technologies in the field of electromagnetism are emerging,and we are entering the fifth generation of mobile communications at a very fast pace.The technology of communication devices around us is changing rapidly and the number is growing exponentially.All the changes brought about by the technology upgrade have placed higher demands on electromagnetic microwave devices,such as smaller size,better radiation performance,lower transmission loss,etc.In order to cope with as well as meet these new requirements,a lot of new research has been started on microwave devices.In the past two decades,Artificial Magnetic Conductor(AMC)has attracted attention and developed rapidly as a novel electromagnetic metamaterial.Artificial magnetic conductor is a structure consisting of a periodic arrangement of metallic conductors,dielectric substrates and ground plates with electromagnetic band gap properties that can be used in many types of microwave devices to improve their various desired properties.In addition,artificial magnetic conductors possess advantages such as easy processing and low cost due to their periodic nature.The purpose of this paper is to develop a low-loss amplitude and phase feeding network implemented using artificial magnetic conductors to improve the radiation efficiency of antenna arrays.In this paper,we propose the first method to reduce the radiation loss in microstrip coupled structure and amplitude phase feed network using artificial magnetic conductor structure reasonably and efficiently for the insertion loss of broadband Schiffman-type phase shifter and energy loss on antenna feed network.The main contents of this paper include the following aspects.1.This paper combines the background of the current era,a comprehensive and systematic description of the development of research on artificial magnetic conductors and the change of various technologies,and the significance of the application of artificial magnetic conductors in various microwave devices.The research gap of artificial magnetic conductor(AMC)in reducing insertion loss in microstrip coupling structures and amplitude phase feeder networks is pointed out at this stage,and finally the arrangement of this paper is outlined.2.This paper introduces the background and theoretical basis related to artificial magnetic conductors,including surface wave properties and in-phase reflection properties.For the structure of artificial magnetic conductor,the method of simulating electromagnetic band gap diagram using electromagnetic simulation software and the method of parameter extraction using SOL technique are given in detail.This paper also explores the influence of several main parameters on the electromagnetic bandgap in the artificial magnetic conductor structure,and points out the primary and secondary relationships,which are of certain guidance for the design of the artificial magnetic conductor structure.3.A wideband Schiffman-type 90° phase shifter with a center frequency of 15 GHz is designed and used as a basis to improve the design for insertion loss.The insertion loss of the Schiffman phase shifter is greatly reduced by about 60% by using an artificial magnetic conductor structure operating in the same frequency band.The effect of the nylon screw hole position on the performance of the phase shifter was systematically investigated when the artificial magnetic conductor structure and the phase shifter were actually assembled,and the optimal solution was selected for processing and testing.4.A circularly polarized planar antenna array with a center frequency of 28 GHz is designed,and a series-fed sequential feed network is used to cover it with an artificial magnetic conductor structure working in the same frequency band,which reduces the spatial radiation loss of the amplitude phase feed network.Without affecting the radiation performance of the antenna,the benefit is finally reflected in the radiation efficiency,which is increased from 83% to 94% for the antenna array. |
