Research On High Performance Antennas And Arrays For 5G Mobile Communication Systems

The fifth generation mobile communication will have a huge impact on people's lives,such as the cloud technology,internet of things,automatic driving technology and virtual reality technology,etc.However,with the increasing demand of wireless communications,the spectrum shortage of radio has become a serious problem and the operating frequency of5G communication will be extended to millimeter-wave bands.The high-performance antennas are required for the high-speed and low-latency of 5G communication systems.There are four main research works in this thesis as follow.Firstly,a broadband polarization-reconfigurable slot antenna and array with compact feed network are proposed.The proposed novel microstrip?MS?-slot line?SL?-coplanar waveguide?CPW?feed structure has the length of only 0.2?₀.By switching three PIN diodes for controlling the phase differences of the electric field in two SLs,the linearly polarized?LP?,left-hand circularly polarized?LHCP?and right-hand circularly polarized?RHCP?states are reconfigured.By utilizing the proposed feeding network,a 2×2 polarization-reconfigurable antenna array with three polarization states is designed.The simulated results coincide with the measured ones well,and the peak gain reaches 14.7d Bi.Due to the low loss and compactness of the MS-SL-CPW feed structure,this design can be extended to a larger array without increasing the complexity,which can be potentially used in the 5G base stations.Secondly,a novel miniaturized half-mode Yagi microstrip magnetic dipole antenna with low-profile is proposed.Combined with the printed electric dipoles,a compact broadband dual polarized?DP?antenna with endfire radiation is designed.By using the microstrip magnetic director as the metal ground of the balun feed network of the electric dipole,the arrangement can be more compact.Taking the element space of 0.5?₀,the 1×4 antenna array is designed and verified by the measurements.A DP beam coverage of±43°in the endfire direction is obtained.The overlapped 10-d B impedance bandwidth is from 23.8 to 30.1GHz?23.7%?,which covers the 5G bands of n257 and n258.The profile of the array is only 0.09?₀.The bottom of the proposed DP antenna is complete metal ground so no any clearance is required and it is easy to be integrated with chips,PCB and 5G mobile terminals.Thirdly,a broadside and endfire dual-polarized millimeter-wave beam scanning arrays with compact structure are proposed.The miniaturized dual-polarized endfire antenna,composed of a compact electric dipole and a half-mode magnetic dipole,has a compact size of only 0.32?₀×0.42?₀.The dual-polarized stacked patch antenna is utilized as the element of the broadside array.Two groups of endfire antenna arrays arranged in 1×2 and a 2×2broadside antenna array can both cover the 5G bands of n257 and n258,and scan in a range of±45°at both endfire and broadside directions.Due to its compact and low profile structure,the array is easy to integrate with PCB,chips,5G terminals and other wireless applications.Finally,a broadband millimeter-wave dual-polarized beam scanning array with the characteristic of broadside and endfire radiations is proposed.The antenna element is a stacked patch slot-coupling fed by two orthogonal sides,which have high isolation.The 3×3dual-polarized array is formed diagonally with the element space of 0.36?₀.With the appropriate phase at each port,the array can both scan in the broadside and endfire direction,and realize beam coverage in the upper hemisphere.Due to its characteristic of broadband,wide beam-scanning coverage and low profile,this beam scanning array is easy to integrate with terminals.It can be potentially used in the wireless mobile terminal for 5G applications.