Design And Resrearch Of Dielectric Antenna And Multiband Filter Applied In Wireless Communication Systems

With the advent of fifth-generation mobile communications,wireless communication systems are rapidly developing.Antennas,as components of mobile terminals and base stations,has to satisfy the requirements of miniaturization and multi-band.As a new type of antenna,the dielectric antenna has attracted much attention due to its small size,simple structure,and no surface wave loss.On the other hand,with the wide application of wireless LAN,multi-frequency filter as a communication front-end device,its miniaturization,multi-band and high-performance,etc.have also become a research hotspot.The main contents of this paper mainly include the following aspects:(1)Based on the theory of rectangular dielectric antennas,a dual-frequency rectangular dielectric antenna was designed by means of microstrip-slot-coupled feed.The design process is to first estimate the size of the dielectric resonator based on the designed operating frequency,and then use a microstrip-slot-line coupling to feed a rectangular dielectric resonator,where the slot line also acts as a radiating section to generate a resonant mode,broadening the frequency band of the dielectric antenna.Then,using the high-frequency electromagnetic simulation software Ansoft HFSS,the feed structure of the antenna and the size of the resonator are simulated and optimized.Finally,the antenna of the design is completed and the simulation is in good agreement with the test results.In addition,because the designed medium antenna has the advantages of ground profile,easy processing,low cost,etc.,it is easy to integrate with the system circuit.(2)It is proposed a miniaturized dual-passband filter using a four-mode resonator based on multi-step impedance resonator loaded.Because the four-mode resonator has symmetry characteristics,its equivalent circuit was analyzed to obtain the admittance formula by the even-odd mode method.At the same time,the principle of the equivalent LC component of the microstrip line is used to further analyze the admittance formula of the even-odd mode.By analyzing the resonant current and the parameters of the resonator,the appropriate physical dimensions of the filter are selected,and then multiple zeros are formed through the source load coupling to improve the selectivity of the filter.(3)A multimode square ring loaded resonator(SRLR)is presented,which consists of a ring resonator and six open stubs.Because of the central symmetry of the resonator,its equivalent circuit was analyzed in detail by the even-odd mode method.Based on this,the parameters of the SRLR resonator were scanned,and the resonant frequency of the SRLR resonator was analyzed in detail.alternative relation.In order to realize the miniaturization ofthe circuit,the branches of two SRLR units are folded and a balanced three-pass bandpass filter with a wide stop band is designed.Furthermore,a pair of open-loop stubs and cross-shaped stubs are added to the symmetric plane of SRLR to enhance the common-mode(CM)suppression across the given frequency range and DM response remains almost intact.To verify the proposed design method,a tri-band balanced filter operating at 2.4,3.5 and 5.2GHz has been designed to validate the proposed concept.Measured results exhibit good agreement with the simulated ones.