Design Of High-Gain Dielectric Resonator Antennas And Dielectric Lens Antennas

The rapid development of radio systems puts much higher performance requirements for antennas.High-gain antennas can effectively compensate long-distance transmission path losses,which are widely utilized in various long-distance wireless systems.Because of their advantages such as no metal losses and surface waves,high radiation efficiencies and flexible design,dielectric resonator antennas have attracted great attention.Dielectric lens antennas have the characteristics such as high gain,high polarization purity,flexible design,and no feed blockage.They have been widely used in long-distance communication systems.Therefore,in this thesis,high-gain dielectric resonator antennas and dielectric lens antennas have been studied.Main contributions of this thesis can be summarized into following three parts.1.A novel high gain circularly polarized dielectric resonator antenna is presented.A hybrid stepped ring slot is used to excite the orthogonal modes in the dielectric resonator.Four parasitic metal plates are sequentially placed around the dielectric resonator.The dielectric resonator and the parasitic plates radiate together to achieve wideband circular polarization.In addition,a partially reflective surface is introduced for greatly enhancing the broadband gains while further improving the AR characteristic.The measured CP bandwidth is 53.6%and the measured peak gain is 14.2 dBic.Wideband circular polarization and high gain characteristics make the proposed antenna attractive in radio system applications.2.A novel dual-polarized dielectric resonator antenna array based on the substrate integrated waveguide(SIW)feeding technique is designed.Quasi TE₄₁₀ and TE₁₄₀modes in the SIW resonator are utilized to excite the orthogonal modes TE₁₁₁^x and TE₁₁₁^y of the array element in the 2×2-element array,respectively.Thus,the dual-polarization radiation is realized,and the feeding network is simplified effectively.Furthermore,a dual-polarized 4×4-element array is proposed using the 2×2-element array as the subarray and designing the feeding network.The measurements of the 4×4-element array prototype are in good agreement with its simulations.The overlapping bandwidth of the two ports is 190MHz(9.53-9.72 GHz).The gains of the two polarization are 16.7 dBi and 16.6 dBi,respectively.The port isolation is greater than 30 dB throughout the operating band.The characteristics of high gains,simple dual-polarization feeding structure,high port isolations,low cross-polarization levels and large front-to-back ratios make the proposed antenna array attractive in radio system applications.3.A novel high gain 3-D printed dielectric lens antenna and a linear array are designed.The SIW-fed printed Log-periodic dipole array is used as the feed source,which is compact in size and easy to be integrated with the planar circuit.Based on the proper design of the lens structure and 3-D printing technology,a single dielectric material can be equivalent to a multi-layer material structure.Wideband high gain performance is realized while the fabrication complexity and cost are reduced.The operating band of the proposed antennas covers the X-band.Its peak gain is 13.45 dBi,its average gain is 12.5 dBi,and its 1-dB gain bandwidth is 26%.Then,the eight-element linear array is proposed by combining the dielectric lens antenna and the SIW feeding network.Finally,the above antennas and array are fabricated and measured,and the measurements are in good agreement with the simulations.The lens antennas are suitable for X-band wireless system applications.