Research On Multi-mode Cavity Antenna

With the rapid development of modern communications,people are increasingly demanding the quality of communication systems.A good communication system means that people enjoy better communication quality and faster communication speed during communication.According to the Shannon formula C=B log2(1+S/N),in the case of a certain signal-to-noise ratio,the enhanced bandwidth of the system can improve the communication rate.Therefore,it is significant to study the RF device with wider bandwidth.low-loss,high-radiation efficiency.High power-handing antennas have been the focus of research by researchers,and these characteristics are prerequisites for ensuring the quality of communication systems.In the case of ensuring the performance of the communication system,researchers usually focus on how to miniaturize and integrate the device.For example,the antenna and filter integrated filter antenna can simultaneously have both functions of both such as filtering,transmitting and receiving signals without increasing the volume,implementing broadband using multimode.As a key part of wireless communication systems,RF devices account for a relatively large part of the system.Therefore,the miniaturization and integration of the radio frequency device can greatly reduce the size of the entire wireless communication system.In this paper,the simulation software CST was used to carry out the modeling analysis,and the appropriate theoretical calculations are carried out.Finally,the processing test is carried out to verify the validity and correctness of the design method and ideas proposed in this paper.First of all,a class of triple-band and triplex cavity-backed slot antenna is proposed by using the three resonant modes in a one metal cavity: TE011,TE101 and TM110 mode,simultaneously.These three resonant modes can be excited by changing the position of the feeding slot without any extra components configured inside the cavity.By opening a single radiation slot,a single band triple-mode cavity-backed slot antenna is achieved.By opening three slots at three side walls of the cavity,a triplex cavity-backed slot antenna is realized with three radiation directions at three different operation frequencies.Moreover,a triple-band antenna can be formed by combining of a single slot antenna and three input ports using the same rectangular cavity.Finally,a triple-band multi-directional cavity-backed slot antenna prototype and a triplex triple-band cavity-backed single slot antenna prototype are fabricated and tested.The tested results are in good agreement with the simulated results,which indicates the feasibility of the proposed deign.Secondly,a class of circularly-polarized(CP)cavity-backed slot antenna with enhanced gain is formed up.All the proposed antennas are implemented in a single rectangular metal cavity.One slot is formed at the bottom side of this cavity as a feeding slot to excite two orthogonal resonant modes.Slot antenna is then constituted at the opposite side of the feeding slot to radiate electromagnetic(EM)wave.A two-element array is further implemented to improve the radiation gain with 3 dB enhancement without size increment of the original antenna.Finally,two CP cavity-backed slot antennas are fabricated and tested for experimental verification of the proposed design methodology.Good agreement between measurement and simulation shows the feasibility of the proposed cavity-backed slot antenna.At the last of this paper,a class of bandwidth-enhanced full-metal cavity-backed slot filtenna is proposed.The design is constructed by three resonators.They are two resonance windows and one resonance cavity.As a consequent of that,three resonance modes are achieved using a single cavity.By using this resonance window,the 10-dB frequency bandwidth of the proposed cavity antenna has wide fractional bandwidth of 20%.To the authors' best knowledge,the proposed filtenna achieves the widest fractional bandwidth among those published full-metal cavity-backed slot filtennas.Moreover,a fifth-order filtenna is also designed to further broaden the 10-dB fractional bandwidth to 24%.Finally,an antenna prototype was fabricated and tested for experimental verification of the proposed design methodology.Good agreement between measurement and simulation shows the feasibility of the proposed wideband full-metal filtenna using resonance window approach..