Research On Conformal Orbital Angular Momentum Array Antenna And Feed Network

With the arrival of the era of 5G everything interconnection,faced with the dramatic increase of information transmission,the communication rate and channel capacity also put forward a higher demand,the spectrum resources appear increasingly tense under the development of ever-changing communication technology.Orbital Angular Momentum(OAM),as a new mode of information modulation,has an infinite number of orthogonal modes theoretically,which can effectively solve the problem of spectrum resource shortage and has a broad application prospect.Through investigation,it is found that the current research on OAM array antenna mainly focuses on Uniform Circular Array(UCA)and planar structure,while the research data on conformal structure is relatively few.At the same time,the traditional feed network has complex structure and can only generate a single mode OAM vortex wave with fixed phase difference,and most of the generated beams are normal beams or beams with fixed deflection direction.Therefore,the research work on OAM in thesis can be divided into the following three points:1.Taking advantage of the fact that microstrip Yagi antenna can be conformal with any curved carrier,an OAM array antenna with microstrip quasi-Yagi antenna is designed in this paper.The simulation results of return loss,electric field amplitude diagram,electric field phase diagram and three-dimensional gain diagram show that the designed microstrip Quasi-Yagi antenna OAM array can generate OAM vortex electromagnetic wave with good wavefront structure.The model structure is processed and tested,and the results show that the model can effectively generate electromagnetic vortex waves with different OAM modes.2.Based on the microstrip transmission line theory,three kinds of "one in,eight out" feed networks are designed,which are equal amplitude and equal phase、equal amplitude 45°phase difference and equal amplitude 90°phase difference respectively.And then processed and tested,the amplitude and phase of each output port of the feed network are within the acceptable error range.Combined with OAM array antenna,beams with different OAM vortex characteristics with mode values l=0,l=1,l=2 are generated.And PIN diode is introduced to control the length of microstrip transmission line by controlling the on-off of PIN diode,so as to cause different phase delay,to control the different phase difference of each output port of the feed network,and realize the mode reconfiguration of OAM vortex wave.3.Based on the theory of phased array scanning and the principle of vortex electromagnetic beam deflection,the phase distribution on the aperture of phased array required to realize vortex beam scanning is derived according to the formula.The beam scanning effect of Orbital Angular Momentum vortex electromagnetic wave is verified by the designed OAM array antenna,and the deflection performance of vortex electromagnetic beam is discussed and analyzed.The simulation results show that the OAM array antenna can effectively rotate the vortex electromagnetic beam in a certain airspace.