Design Of Filtering Dielectric Resonator Antennas

The upgrading and continuous development of wireless communication system puts forward higher technical requirements such as miniaturization,integration,high gain and low profile for its key component antenna.The filtering antenna has both radiation characteristics,filter characteristics and impedance matching functions.It can also effectively reduce the size of the passive circuit and meet the requirements of miniaturization design.Dielectric resonator antenna has advantages such as small loss,high radiation efficiency,high power capacity,easy excitation and diversified radiation modes.Combining the filtering antenna with the dielectric resonator antenna,the filtering dielectric resonator antenna will have their advantages and potential application value for wireless communication system.Therefore,a filtering dielectric resonator antenna with high band-edge selectivity and a high gain filtering dielectric resonator antenna are designed.The main contributions are summarized as follows.1.A filtering dielectric resonator antenna(DRA)with high band-edge selectivity is proposed.This DRA is fed by a simple hybrid feeding structure consisting of slot coupled feeding and coaxial probe feeding.The hybrid feeding structure excites two fundamental modes-TE₁^y_?1 modes,which realizes a wide impedance bandwidth of 19%(1.71 GHz-2.07 GHz).Besides,the hybrid feeding structure also establishes a cross-coupling mechanism that introduces two radiation nulls beside the passband and also implements the filtering characteristic.By introducing a shorted stub at the end of the microstrip feedline,the band-edge selectivity of the filtering dielectric resonator antenna is enhanced.Finally,the changing-rates of gain at higher and lower band-edge are 31.5 d B/80 MHz and 30d B/65 MHz respectively.The measured results show that the bandwidth is 19%(1.732GHz-2.096 GHz),and the average gain in passband is about 5 d Bi,which are in good agreement with the simulation results.2.A high gain filtering dielectric resonator antenna is proposed.Firstly,the traditional microstrip-coupled slot is changed into two separate stepped slots,then a pair of opened stubs with the same size are added to the microstrip feedline,and a shorted via is added to the substrate to short the ground and the microstrip feedline.Two radiation nulls beside the passband are introduced,which bring the filtering performance.Secondly,the stacked dielectric resonator antenna structure is adopted to realize the structural characteristics of low profile and the radiation characteristics of high gain.The measured results show that the profile of antenna is only 0.133?₀,the average gain in passband is about 9 d Bi,the peak gain can reach 9.7 d Bi and the bandwidth is 26.8%(5.16 GHz-6.76 GHz),which are in good agreement with the simulation results.