Research On Plasma Array Antenna And Its Arrangement

With the rapid development of communications,higher and higher demands are proposed on the performance of the antenna.Plasma antenna has been researched for its advantages of reconfiguration and low coupling,small volume and light mass which compared with metal antenna.It has attracted wide attention in civil use,commerce and modern industry.The plasma antenna working in terahertz band has gradually entered people`s horizons because of the large amount of data transmitted in the terahertz band and the advantages of the plasma antenna.The research background,current situation and significance of plasma antenna are introduced,and then the basic properties,generation methods and propagation characteristics of electromagnetic wave in plasma antenna are described.The plasma monopole antenna is studied and analyzed.Compared with the same size metal antenna,when the plasma frequency is much larger than the collision frequency,the plasma is more like metal,and the performance of them is closer.The antenna performance will be better at the condition of higher plasma oscillation frequency,thinner thickness of glass tube,lower collision frequency.Next,on the basis of plasma monopole antenna,the plasma antenna array with four and six elements is studied.It is found that when the plasma is excited but the antenna is not excited,the element can be regarded as a reflective conductor,and the increase in the number of antenna elements will lead to the increase of mutual coupling,which will reduce the gain of the element.By changing the plasma parameters of the element on the array,the radiation pattern of the antenna will be changed accordingly,omnidirectional scanning can be achieved in a plane which perpendicular to the antenna.A new kind of terahertz plasma-metal hybrid yagi antenna has been proposed on the basis of plasma antenna,in which reflected oscillator is replaced with right-angle reflector.The structure is designed by the theory of plasma antenna and yagi antenna,and the parameters are preliminarily determined.And then electromagnetic simulation is carried out to examine the performance parameters of the yagi antenna,such as the return loss,gain,voltage standing wave ratio and radiation pattern,in which the condition of different distances between the vertex of angle reflector and dipole is considered.Contrasted with those of the antenna without angle reflector,the result shows that the structure proposed in this article greatly improved the gain and the front-to-rear-ratio.