Research On Filtering Antenna Array For 5G Wireless Communications

In recent years,the wireless communication industry is building lighter,thinner and smaller products with the same or more functions.The integration of filter and antenna is one of the important channels for the miniaturization of electronic systems.Therefore,many researchers at home and abroad combine the filter and antenna by using the idea of integrating the filter function into the antenna.In this way,the transmission line connecting the two is omitted,and the volume of the filter antenna is greatly reduced,the compactness of the RF front-end system is strengthened,and the goal of miniaturization and integration is realized without changing the original radiation performance and filtering response of the antenna.Based on the fusion design method of filtering antenna,this paper realizes the high selectivity of filtering antenna without adding additional filter circuit.The following filtering antennas are designed respectively:Firstly,a low profile millimeter wave filtering antenna unit is designed.By designing a bifurcated microstrip feed structure with an open end on the feed and introducing a parasitic patch at the appropriate position of the radiation patch,the antenna achieves a radiation performance with an average gain of 7d Bi at 24-25.86 GHz,and introduces a radiation zero at the appropriate frequency point at the edge of the working band.Without changing the radiation performance of the antenna,the working band is broadened and the out of band suppression level of 19.5d B is achieved.Secondly,in order to improve the gain performance,two filtering antenna arrays are designed based on the millimeter wave filtering antenna unit.On the basis of improving the radiation aperture,a common parasitic patch array structure is designed,and a millimeter wave filtering antenna array with low radiation aperture and high out of band suppression is realized under the condition of fixed cell spacing.Since the common parasitic patch structure does not significantly improve the gain,a 4 × 4 millimeter wave filtering antenna array.The feed adopts a quarter power distribution network,and the appropriate cell spacing makes the antenna array achieve an average in band gain of12 d Bi and an out of band suppression level of 16 d B.Finally,a simple compact filtering antenna is designed.Two simple filter structures are used to make the antenna produce filter response in a specific frequency band.They are respectively to introduce the radiation zero point at the edge of the low frequency band by etching the double slot structure on the rectangular patch,and to improve the filter response of the high frequency band by introducing a U-shaped metal strip under the dielectric substrate and connecting it with the coaxial feed.The filtering antenna has a simple structure,operates at 5.19-6.29 GHz,has an average gain of 8.2d Bi in band,and achieves an out of band rejection level of 18 d B.