Investigation Of Dual-Band Co-Aperture Antenna Based On Filtering Antenna

With the development of 5G in the world,more and more spectra are needed.Multi-band Multi-standard communication systems have become a trend.The coexistence of different frequency bands in the 2G/3G/4G/5G system will make the space resources for antenna placement tight.Multi-band co-aperture antenna arrays are significant to alleviate the problem of the space resources for antenna placement.However,in a compact space,the problem of mutual coupling and mutual shielding between antenna units working in different frequency bands becomes particularly serious.The application of the filtering antenna helps to solve the problem of different frequency coupling between different frequency antenna units in a compact space.Therefore,the research and design of filtering antennas and the design of dual-band coaperture base station antennas based on filtering antennas are very meaningful.This paper studies the filtering antenna without additional filtering circuit and the dual-band co-aperture base station antenna based on the filtering antenna.The specific content is as follows:1.A filtering dipole antenna with a simple structure based on a feed balun to achieve filtering applied in base station.This paper proposes an antenna with a low-pass filter response,which is realized by the improvement of the balun structure of the dipole antenna itself and the slit on the vibrator arms of dipole antenna and without adding additional filters or even other parasitic structures.The antenna proposed in this paper can cover an impedance bandwidth of790-862 MHz.For the out-of-band frequency band 880-960 MHz,it can achieve a maximum suppression of 14 d B.2.A compact dual-band dual polarization co-aperture antenna based on the filtering antenna.The antenna operates at DCS band(1710-1880 MHz)and WCDMA band(1920-2170MHz).More than 30 d B polarization isolation has been obtained by the symmetrical feeding method.And isolation in the different bands of 15 d B can be realized by utilizing filtering antennas,which can greatly reduce the pressure of filter design.The width of the present array is only 140 mm.3.A miniaturized dual-band dual polarization co-aperture antenna based on the filtering dipole antenna.This antenna operates at low band of 1710-2170 MHz(23% relative bandwidth)and high band of 2300-2700 MHz(16% relative bandwidth).The aperture size of the antenna array is only 50 mm*50 mm,which is 0.36 wavelengths of the central frequency,realizing miniaturization.In a compact space,using filtering dipole antennas based on an open microstrip line,the co-polarization and inter-frequency isolation of the antenna array can reach 15 d B and above.The radiation patterns are all stable for the base station application.