Investigation Of Wideband Low-profile Dielectric Resonator Antenna With A Lattice Structure

High speed and low power consumption are the two core requirements of the fifth generation mobile communication technology?5G?.At the same time,considering the future mobile terminal devices highly demand for thinness,it is of great research and application value to design a broadband,high-efficiency and low-profile antenna in the field of antenna technology.Compared with the traditional microstrip antenna,dielectric resonator antenna?DRA?has prominent advantages in broadband,miniaturization and low loss,so it is considered to be very suitable for the design of broadband,low-profile and high efficiency antennas.The design of broadband low-profile DRA is a hot and difficult research topic,and there are a few frontier reports at present.Most low-profile DRA designs can be realized by dielectric materials with high dielectric constant,but the high dielectric constant DRA usually has a high radiation Q value,thus its working bandwidth is narrow.Therefore,it is very meaningful and challenging to design a DRA with broadband and low-profile advantages.In this paper,the research background and significance of broadband low-profile DRA are briefly introduced.The domestic and overseas research status for DRA is investigated,the advantages and disadvantages of the existing research are summarized.Then the basic theory of DRA is given,including the working principle of dielectric resonator,the analysis method of rectangular DRA and several common feeding methods of DRA.Based on the basic theory of DRA and previous research achievements,the research work of this topic is carried out in depth.Firstly,a new kind of broadband low-profile DRA with a lattice structure is presented.The antenna is excited through a slot feeding structure.The top dielectric resonator broken up into a lattice structure is adopted to achieve a wide operating bandwidth in a compact size,which makes it suitable to be arrayed.A backed cavity based on substrate integrated waveguide technology is introduced to reduce the unwanted radiation from the surface wave.Measured results show that the prototype can achieve an impedance bandwidth of 39%and a peak gain of 9.6 d Bi,the height of the antenna is 0.1?₀.Secondly,a novel technique to design a broadband low-profile circularly polarized DRA with a lattice structure is proposed for the first time.Two resonant modes ofandcan be simultaneously excited through a cross-slot to constitute a wide operating bandwidth.On this basis,its reconfigurable version,which can operate in left-handed circular polarization,right-handed circular polarization,and linear polarization states,has been further presented.The latter possesses a simple design procedure to implement the reconfigurability since all the reconfigurable feeding circuits are isolated from the radiating DRA by the ground plane and only five PIN diodes are needed.Measured results indicate that the reconfigurable prototype can achieve a 3-d B axial ratio bandwidth of 20.7%for CP states,an impedance bandwidth of 29.6%for LP state with a cross-polarization level of better than-20 d B,and a peak gain over 7.3 d Bi for all states.The height of the antenna is 0.1?₀.The proposed antenna can be used for polarization diversity applications of the modern wireless system.Finally,a wideband low-profile DRA for mobile terminal Ai P application with a lattice structure is proposed.One centrally-placed strip dielectric resonator is excited at first and then coupled with the periodic dielectric blocks around it.By combining the two resonant frequencies of the strip dielectric resonator mode and the periodic dielectric blocks mode,the antenna can achieve a wide operating bandwidth.At the same time,the total height of the antenna is 0.07?₀?0.06?₀ when the bottom substrate is excluded?.Measured results show that the prototype can achieve an impedance bandwidth of 24%and a peak gain of 7.92 d Bi.On the one hand,the antenna is consistent with the Ai P design concept.,which meets the requirements of low-profile and broadband coverage faced by the antenna design of mobile terminal.On the other hand,it will be used in other applications such as vehicle communication fed by coaxial probe if the substrate on the bottom is removed.Therefore,the antenna possesses a broad application prospect.This study provides a new idea for antenna design of broadband low-profile dielectric resonator and gives a good reference for antenna engineers.