Research And Design Of Novel Orbital Angular Momentum Antennas For C Band

Vortex electromagnetic wave with orbital angular momentum(Orbital Angular Momentum,OAM)antenna can be used to improve the spectrum utilization and it has an important application value in the field of electromagnetic field and communication.In this paper,the new structures and propagation characteristics of OAM antenna for C band are studied.The main research contents and innovations are as follows:First,the design of a low sidelobe OAM antenna for a "split" sprial phase plate.A series fed microstrip antenna array based on the Chebyshev synthesis method is proposed,which is applied to the design of K band antenna.The antenna array side lobe is reduced by the combination of impedance converter and chip width weighted Chebyshev distribution.The antenna bandwidth is from 23.7 GHz to 24.4 GHz,the gain of the transmitting antenna is 21.2dBi,the receive antenna gain is 17.5dBi,the side lobe is-21dB.On this basis,a low sidelobe OAM antenna with "split" SPP is proposed.Multiple orbital angular momentum modes are realized through a "split" type of rotating phase plate:l=±2,±3,±4.The antenna eventually loaded two layers of Fabri cavity to improve the antenna gain and the OAM antenna has been increased from 13.7dBi to 21.2dBi by 7.5dBi.Second,the design of a novel multi-modal vortex electromagnetic wave circular array antenna.A "crossing" feeding network structure based on the cascade of four couplers is proposed and the phase change required for the three modes of l=-1,0,1 is realized.The microstrip antenna element of 2×2 is attached to the four output ports of the feed network,respectively.It increases the antenna gain from 7.5dBi to 11.5dBi by increasing 4dBi by loading the Fabri cavity.The result of the test is that the bandwidth of the three modes is 5.2 GHz-6.4 GHz(Absolute bandwidth 1.2GHz).The gain of the three modes of l=-1,0,1 is 8dBi,8.2dBi and 11.7dBi are consistent with the simulation results.Third,the analysis of propagation characteristics of a vortex electromagnetic wave antenna.In this paper,we use dipole array antenna to analyze the propagation characteristics of the array radius,the number of orbite angular momentum,the propagation distance to the phase and gain of the vortex electromagnetic wave,and the electric field distribution in the far field.