Research And Design Of Compact Dielectric Resonator Antennas

In recent years,due to the immunity of skin effect,the dielectric resonator antenna(DRA)has been widely researched by the scholars from domestic and overseas and has the advantages such as high radiation efficiency and low Ohmic loss which is suitable for the applications in high frequency wireless communication systems.However,similar to a metal cavity,the DRA has a three-dimensional resonant structure resulting in a large volume occupation of the RF front end when the DRA is used as the antenna terminal.As the main part of the terminal equipment,the size of the antenna is highly related to the integration of devices in the system.Considering the development trend of high integration of devices in modern wireless communication system,the DRA need occupy a smaller volume to realize the compact design.In this thesis,rectangular and cylindrical DRAs have been proposed to realize the compact design for the applications in different scenarios.The proposed DRAs obtain compact or low profile structure without the cost of performance.On the basis of the basic theory of DRA,firstly,the author proposes a frequency reconfigurable DRA which can be applied into the Ku band(12-18GHz)and even higher frequency realizing the substitution of multi-antenna.Within the reconfigurable range,the DRA has a stable radiation pattern,low cross-polarization level and high gain.Afterwards,the author proposes a differentially inserted-fed compact dual-band circularly polarized DRA.To realize the compact design,the inserted differential feeding structure composed of a pair of arc-shaped strips connecting with coaxial probes plays dual roles.It not only excites the fundamental mode HEM₁₁₁ of the DRA,but also brings an additional resonant mode to form the second band without the cost of the size of the antenna.The proposed DRA has a flexible polarization and compact structure.Finally,a differentially coplanar-fed low profile filtering DRA is proposed for millimeter wave applications.To realize a low profile design,a novel coplanar feeding method is presented by incorporating a dielectric resonator and its feeding structure in the same layer which minimizes the assembly errors and makes the proposed DRA owns the same profile as the patch antenna.The filtering function is also obtained realizing the fusion design between the filter and the antenna.In summary,the compact designs of the DRAs in this thesis are obtained from the aspects of frequency reconfiguration,multi-band,function fusion and feeding structure.All the proposed DRAs are more likely to be applied into different scenarios or have lower profile without the increase in antenna size.