Design And Study On Novel Microstrip Differential Filtering Antenna

The advent of 5G era in China has put forward the requirements of smaller volume,more working frequency band and wider bandwidth for modern communication system.In order to reduce the number and volume of components in the system,the filter and antenna of the RF front-end can be integrated to design a filtering antenna,which has the function of frequency selection and radiation at the same time.Differential filtering antennas have excellent electromagnetic compatibility performance,which can effectively suppress environmental noise and device crosstalk.Also,it can be directly connected with other balanced RF front-end devices,which has a wide application prospect.Therefore,several new microstrip differential filtering antennas are designed and manufactured in this thesis.The main contents are as follows:Firstly,two low-profile microstrip differential filtering antennas are designed based on split ring resonators.At the beginning,a second-order differential filter is designed based on the microstrip split ring resonator,and the right-angle microstrip line and the oblique microstrip line are used to connect the filter and the antenna to design a single-frequency differential filtering antenna.The advantages and disadvantages of the two integration methods are compared.Then,a dual-band differential filtering antenna working in the ISM band is designed by adding vertical branches in the split ring resonator and etching slot lines on the antenna patch.Both differential filtering antennas adopt the planar microstrip line design,so the profiles are very low,only 0.008?₀and 0.004?₀.Secondly,two differential filtering antennas with adjustable gain zeros are designed based on cross coupling theory.The second-order split ring differential filter is designed using the microstrip line coupling feed method,and the source-load coupling is introduced by loading the perturbation metal column at the feeder with the strongest electrical coupling between the resonators,and the transmission zeros with adjustable position are generated.Then a pair of monopole stub antennas are connected to the output end of the filter.After adjusting impedance matching,a differential branch filtering antenna with tunable gain zeros to both sides is obtained.In order to have better directivity and higher gain,a differential quasi-Yagi filtering antenna is obtained by using the optimized microstrip quasi-Yagi antenna to replace the branch antenna.Thirdly,a tri-band differential filtering antenna and a differential filtering antenna array are designed based on the improved microstrip-slotline structure.The improved microstrip-slotline structure is introduced into the ground floor of the differential microstrip patch antenna using the proximity coupling feeding method,and the second and third passbands are generated without affecting the fundamental frequency,which widens the working frequency range of the filtering antenna.In order to improve the gain of the filtering antenna,a 4-element differential filtering antenna array with a gain of 10.3d Bi is designed by using a differential feeder to excite the microstrip-slotline structure on the floor and then excite the radiation of the upper patch array element.The thesis has 82 graphs,8 tables,and 97 references.