Study of a Water-Immersed Orbital Angular Momentum Horn Antenna

A new method to improve the resolution for microwave imaging is proposed in this paper by means of a water-immersed orbital angular momentum horn antenna. In order to determine the suitable wavelength of the interrogating radiation in the medium and reduce the big reflection of the incident energy at the interface between the target and the medium surrounding the target, 2.45GHz is selected and the medium is chosen as water in this paper. Moreover, the different orders of OAM may carry more characteristic information of the exposed object to improve the resolution of microwave imaging. The horn OAM antenna is simulated, the calculation results show that the maximum gain is 14.5 dBi and the proportion of the OAM mode $\pmb{1}=-\pmb{1}$ is about 72%, which both can satisfy the requirements for microwave imaging system.