Research On The Design Of Conformal Array Antenna Based On Transformation Optics

The theory of transformation optics has realized the regulation of electromagnetic waves via metamaterial. The application scope of transformation optics can cover all electromagnetic phenomenons. Transformation optics has brought a new view point of controlling electromagnetic waves. The combination of transformation optics and metamaterial technology will expand more research idea and newer findings.In this context, this article proposed a novel method to design the conformal array antenna based on the application of transformation optics in the conformal design of source, which takes the application of transformation optics in the source conformal research as breakthrough point, and gets equivalent design of planar array antenna and conformal array antenna through the equivalence demonstration of antenna and source and the discretization of continuous source. According to the one to one correspondence relation of the coordinate mapping, the design of conformal array antenna with the same characteristics will be realized via the design of the planar array antenna. This design thought expands the research of the source theory to the antenna that is closer to reality and transforms the design of conformal array antenna to the design of planar array antenna, so as to extend the design theories and methods in planar array antenna to the design of conformal array antenna, which is meaningful to solving the design problem of conformal array antenna used in civil facility and national defense construction. This is the main contribution of the article. Two kinds of concrete structure are put forward in the article using this design idea.The first structure uses the model of transforming the line source to the surface source and the half-wave dipole antenna. The equivalent design of line dipole antenna array and spherical conformal dipole antenna array is realized through the equivalence demonstration of dipole antenna and current source and the discretization of continuous line current source and spherical current source. The transformation media, the antenna feeding, and the dimension of the transformed antenna can be calculated through transformation optics theory. Simulations prove if the line dipole antenna array is designed with the required properties, the spherical dipole antenna array with the same properties can be acquired through the calculation formulas. Through changing the axial spacing of dipole antennas and the distribution density, simulation results show that they have little effect on the equivalence result, that is to say, it’s feasible to choose proper space and density to decrease the size of the whole array and thus it can reduce the production cost.Since the radiation property that the line dipole antenna array can realize is limited, by contrast, the application of planar array antenna is wider, especially in the field of the phased array scanning. To expand the application scope of this design idea, the model of transforming the planar source to the spherical source is put forward. Meanwhile microstrip antenna is introduced as array antenna unit, which is easier to get double polarization, circular polarization, double band and so on, and has stronger directivity than dipole antenna. It’s based on these two point to improve the first structure. The equivalent design of planar microstrip antenna array and spherical conformal microstrip dipole antenna array is realized through the design of microstrip antenna, the equivalence demonstration of microstrip antenna and source and the discretization of continuous planar current source and spherical current source. Simulation results show that the space of microstrip antenna array has effect on the equivalence result, and the space of the direction perpendicular to the equivalent magnetic current has greater impact, which provides guidance for future conformal array antenna research using transformation optics.