Design Of Polarizer Based On 3D Printing Technology And Its Application In Antenna

In contemporary wireless communication technology,circularly polarized antennas can effectively solve the problems of polarization mismatch,multipath effect and Faraday effect,so they are widely used in various communication systems.As an effective method to realize circular polarization radiation,polarizer has been widely concerned.It usually has the advantages of stable performance and flexible application to different types of antennas,and is an important RF/microwave device with great research value.3-D printing technology is an emerging additive processing process,which can competently process complex and heterogeneous structures compared with traditional processes,and also has the advantages of saving time,labor and materials.Currently,this technology has been widely used in various fields such as agriculture,medical and aviation,and has also received a lot of attention in the microwave/RF field in recent years.This paper aims to combine 3-D printing technology with polarizer design,take the advantage of the former technology,propose several new polarizer designs,and apply them to circularly polarized antennas.The specific innovation results include the following three parts.1.Proposed an annular dielectric polarizer.Most common dielectric polarizers are planar structures,and there is less research on annular structure,which can effectively solve the problem of polarization conversion of electromagnetic waves in azimuth.Therefore,this part of the study addresses this problem and discusses the operating and design principles of the polarizer in the case of annular continuous aperture and segmented aperture,respectively.Two antenna designs are proposed,an omnidirectional antenna and a multibeam antenna with full azimuth scanning,using a biconical structure and a corner reflector as the feed sources respectively.Both antennas are 3-D printed in one piece,which have the advantages of broadband and stable performance.2.A single dielectric slab polarizer is proposed.The traditional dielectric polarizer is mostly a periodically arranged multi-dielectric slabs structure,which is more complex and larger in size.This part improves the traditional design and proves through simulation and experiment that the simplified single dielectric slab can also realize the polarization conversion of broadband.In addition,a multi-beam annular antenna array with omnidirectional scanning capability is proposed based on this polarizer.The metal and dielectric parts of this array are realized by metal and dielectric 3-D printing technology,respectively.The operating bandwidth covers almost the whole Ka-band and the half-power beamwidth and 3-d B axial ratio beamwidth cover the whole azimuthal plane during the scanning.3.A waveguide built-in polarizer is proposed.In addition to external polarizers,waveguide internal polarizers are also widely used.In this section,a linearly tapering double-ridge polarizer is proposed,which is designed inside a dielectric-filled circular waveguide by means of a complementary structure.Based on this structure,an open-ended waveguide antenna element and a 1×4 array are proposed.Both the element and the array are formed in one piece by dielectric 3-D printing technology,and the waveguide walls are realized by plating.The two designs can effectively solve the problems of large size,heavy weight and difficult processing of traditional open-ended waveguide antennas.