Research Of Application Of Dielectric Resonator Antenna And Absorptive Frequency Selective Surface Radome

With the improvement of the communication system,the requirements for antenna performance will be further improved,such as:pattern reconfigurable,wide beam and low Radar Cross Section(RCS).Dielectric resonator antennas have advantages of high design-freedom,rich operating-mode and low loss.Meanwhile,they can also meet the increasingly strict requirements of beamwidth and pattern shape in wireless communication systems.Dielectric resonator antennas have received wide attention from researchers due to their significant research value.Moreover,with the increasing progress of detection technology,military equipments such as warplanes,missiles,and ships are increasingly threatened on the battlefield,forcing countries around the world to put forward more stringent requirements for their stealth performance of military equipment in electronic warfare.Absorptive Frequency Selective Surface(AFSS)as radome is one of the hottest research topics in field of reducing the RCS of targets.However,current research mainly focuses on the design of AFSS unit structures that could achieve different performances.Only a few studies report the combination of AFSS radome and antennas to achieve low RCS antenna.In fact,loading AFSS radome above the antenna will have certain influence on the radiation performance of the antenna.Therefore,it is of great value to study the interaction between AFSS radome and antenna,and summarize the design criteria of low RCS antenna.This thesis focuses on three main requirements for antenna performance in communication system.The main research contents of this thesis are as following:(1)A dielectric resonator antenna with pattern reconfigurable and wideband characteristics is designed.Firstly,a rectangular polyvinyl chloride dielectric resonator with nine cavities separated by high dielectric constant blocks is designed.Then,the equivalent dielectric constantε_x of the dielectric resonator is changed by filling/emptying ethyl acetate into the cavity,and the radiation pattern of the antenna is switched between two states.(2)A stacked dielectric resonator antenna with an ultra-wide 3 d B beamwidth is designed.In this work,the 3 d B beamwidth of the antenna on the E and H planes of 2.45 GHz is greater than 200degrees by means of mode synthesis,floor-digging trapezoidal groove,and adding parasitic branches.(3)A low RCS antenna based on band-pass AFSS radome is designed.The gain is enhanced and the out-of-band RCS is reduced.Firstly,a miniaturized band-pass AFSS is designed by using the interdigital structure and improved ring-shaped unit.And then the radome is combined with the antenna.The band-pass AFSS is placed near the half-wavelength above the antenna.A quasi-Fabry-Perot cavity is constructed between the AFSS and the antenna floor to improve the antenna gain by utilizing the partial reflection characteristic of the radome to the oblique incident electromagnetic wave.Meanwhile,the loaded height and performance of the radome to achieve gain enhancement of band-pass AFSS radome are summarized.(4)A low RCS antenna array based on band-pass AFSS radome is designed.The out-of-band RCS reduction of the antenna array is realized.Firstly,a band-pass AFSS is designed by using the cross-shaped structure and ring-shaped unit.Then the radome composed of AFSS is loaded on the top of different antenna arrays.The influence of band-pass AFSS radome loaded on the top of different antenna arrays is summarized.