Circularly Polarized Dielectric Resonator Antenna

With the development and improvement of a wireless communication system,people have more and more requirement for high efficiency,low profile and miniaturization of antenna.Under such a background,dielectric resonator antenna?DRA?has been investigated extensively owing to the merits of low loss,small size,easy integration and broadband.Circularly polarized?CP?antenna received much attention because it achieves good anti-interference capability and can avoid the problems caused by polarization mismatch effectively.In this paper,several CP DRAs with different feeding styles are investigated.The results are as follows:1.A novel circularly polarized substrate integrated dielectric resonator antenna?SIDRA?operating in V-band is proposed.Its feeding structure uses half-mode integrated waveguide?HMSIW?,and the radiation element is an integrated cylindrical dielectric resonator.The energy is coupled through the cross-slots etched on the ground to obtain the circularly polarized radiation.The field distribution in HFSS software shows that the HEM_11?mode is excited in the DRA.The simulation results demonstrate that the antenna has a good resonant characteristic.The impedance bandwidth is 4.1%?from 56.4 GHz to 59.8 GHz?and the axial ratio?AR?bandwidth of the antenna is 3.8%?from 56.8 GHz to 59.8 GHz?,which almost overlaps the whole impedance bandwidth.It shows that the antenna achieves an effective circular polarized radiation during the whole band.2.Next,this paper analyzed sequential rotated feeding technology.Based on this technology,a 2×2,2×8 and 4×4 CP DRA arrays are designed respectively.The antenna element is a linear polarized DRA using microstrip aperture feeding structure.In this design,a parallel one-to-four sequential rotated feeding network is adopted.Each output port achieves equal amplitude and 90 degree phase delay with the adjacent output port according to its equivalent transmission-line model.These three arrays operate in the Ka-band.According to the simulation results,we can see the impedance bandwidth and AR bandwidth of 2×2 array is 11.2%and 3.2%,respectively.The AR bandwidth of 2×8 array and 4×4 array is 3.9%and 6.3%,respectively.The cross-polarization level of these three arrays on the principal plane is lower than-15dBi,which shows the rotated feeding technology can realize circular polarization and low cross-polarization efficiently.3.A new circularly polarized DRA:CP differential-fed DRA,is proposed.In this design,the feeding structure uses microstrip line and the radiation element uses a rectangular DRA.A pair of differential signals are input from the two port of the microstrip line,and the energy is coupled through the cross-slots etched on the ground.The field distribution on the CST shows that TE₁₁₁ mode is excited inside the dielectric resonator.The simulation results show that the impedance bandwidth and the AR bandwidth are 12%and 2.4%respectively.In order to widen the AR bandwidth,a 2×2differential CP DRA array is designed using the sequential rotated technique.The impedance bandwidth and the AR bandwidth of the array are 12.1%and 11.1%respectively.It demonstrates that the AR bandwidth has been enhanced significantly.Both the element and the array realized a good circular polarized radiation.