Study On Planar Complementary Antenna

As the communication scenario becomes more complex and the communication equipment becomes more integrated,the research of planar and high performance antenna becomes more and more important.Compared with traditional planar microstrip antennas,complementary antenna is designed by the combination of electric dipole and magnetic dipole,which exhibit better performance and more flexible design.When the relative position,amplitude or phase of electric dipole and magnetic dipole are different,various radiation characteristics will be produced.However,currently,the research on complementary antenna mainly focuses on the realization of broadside radiation patterns,other kind of patterns has untapped potential.Moreover,due to the need to excite two complementary sources,this kind of antennas is usually large and difficult to realized planarization and integration.In this paper,three kinds of planar complementary antennas with different radiation characteristics are realized based on the study of complementary antenna theory,which enriches the design ideas of complementary antennas.The main work of this article is as follows:(1)An electrically small planar quasi-isotropic complementary antenna is proposed.Electrically small elements,a folded dipole and a pair of capacitively loaded loops are combined on a single dielectric substrate,and coplanar strip lines are used for coupling feeding to excite the equivalent electric dipole and magnetic dipole.The electric dipole and magnetic dipole have the same amplitude and the phase difference of 90°.Therefore,quasi-isotropic radiation pattern has been achieved.(2)Planar end-fire and pattern reconfigurable complementary antennas are proposed.On the basis of alford loop antenna,a radial slot is cleverly etched on the ground to generate the equivalent electric dipole.In combination with the magnetic dipole generated by alford loop itself,the two are in equal amplitude but inverse phase,and thus the end fire radiation pattern is obtained.Furthermore,a planar pattern reconfigurable antenna is realized by improving the antenna and introducing p-i-n diodes.(3)A millimeter wave wideband circularly polarized planar complementary antenna with end fire radiation is proposed.A dual-side printed dipole and an open cavity of substrate integrated waveguide are used to realize the parallel placement of equivalent electric dipole and magnetic dipole.The electric field generated by the two dipoles is superimposed,and the circular polarized wave is obtained in the end-fire direction.In order to broaden the impedance bandwidth and the axial ratio bandwidth of the antenna,the printed dipole element is improved to be a bow-tie type,and a pair of triangular slots is introduced into the waveguide opening cavity.Finally,the broadband circular polarization end-fire performance is realized.