Research On Wideband Circularly Polarized Dielectric Resonator Antenna Based On Slot-coupled Feed

With the rapid development of microwave communication technology,the demand for high-performance antennas is increasing.The circularly polarized dielectric resonator antenna plays an increasingly important role in microwave communication system with its unique advantages such as strong anti-interference ability,high gain and efficiency,easy to feed and flexible feeding methods,among which slot coupling feeding mode is widely used because of its simple structure and easy machining.Recently,under the background that the extensive development and utilization of the radio spectrum has resulted in the increasing shortage of spectrum resources and the increasing amount of communication data has put forward higher requirements for the information transmission rate,wideband wireless communication technology can effectively improve the utilization of spectrum resources and the information transmission rate has been widely applied,and it also requires the antenna has a wider bandwidth.Therefore,the realization of wideband characteristics of circularly polarized dielectric resonator antenna has important research value.Based on this,this paper begins systematic research,and the detailed work is as follows:1.A single-fed wideband circularly polarized dielectric resonator antenna based on a special dielectric resonator structure is proposed.Firstly,a simple quadrangular dielectric resonator is used as the main resonator,and the orthogonal TE mode of the dielectric resonator is excited by the coupling of microstrip line and unequal length cross gap,and the first two axial ratio resonance points f _AR1 and f _AR2 are obtained.Subsequently,the structure of the dielectric resonator was adjusted by introducing a ring dielectric resonator outside the main resonator,increasing the width in the specific region of the ring dielectric resonator,and introducing four connecting arms.Under this adjustment,the values of the axial ratio resonance points f _AR1 and f _AR2 were lowered,and a new axial ratio resonance point was generated at 3.10 GHz.Under the combination of the three axial ratio resonance points,the antenna realizes wideband.The measured results show that the antenna has an impedance bandwidth of 56.6%（1.85–3.30 GHz）and an axial bandwidth of 43.1%（2.00–3.10 GHz）,a peak gain of5.9 d Bi and an average radiation efficiency of 83.2%.2.A single-fed wideband circularly polarized dielectric resonator antenna with parasitic metal structure and inverse f-shaped slot feed is proposed.The antenna is composed of a substrate,a cylindrical dielectric resonator and four curved parasitic metal blocks.An inverse f-shaped slot is etched on the GND.Under the coupling of microstrip and inverse f-shaped slot,the orthogonal HEM mode of the dielectric resonator is excited to obtain circularly polarized radiation.The impedance bandwidth and axial ratio bandwidth of the antenna are improved by optimizing the inverse f-shaped slot structure and the shape and size of the curved parasitic metal blocks.The antenna was simulated,fabricated and tested.The experimental results show that the antenna has an impedance bandwidth of 58.5%（2.61–4.77 GHz）,an axial bandwidth of 55.2%（2.75–4.85 GHz）,and an effective axial bandwidth of 53.7%（2.75–4.77GHz）.Peak gain is 6.84 d Bi and average efficiency is 90.78%.3.A wideband and high gain circularly polarized dielectric resonator array is proposed.In this study,firstly,the feeding method of square-folded microstrip and cross slot coupling is adopted,and the circular polarization of the antenna element is realized by using the phase delay characteristic of the square-folded microstrip.The measured results of the antenna element show that the impedance bandwidth and axial ratio bandwidth are 34.5%（3.17–4.49 GHz）and 17.3%（3.32–3.95 GHz）,respectively,and the maximum gain is 6.9 d Bi.Secondly,in order to further improve the axial ratio bandwidth and gain,the multivariate method was adopted,and a 2×2antenna array was designed by using a sequential rotating feed network.The measured results show that the antenna array has 37.5%（3.06–4.47 GHz）impedance bandwidth,36.4%（3.15–4.55 GHz）axial bandwidth and 12.4 d Bi peak gain.Compared with the antenna element,the axial bandwidth and gain of the antenna array are improved obviously.The antenna array has good performance and can be used in C band satellite communication.