| Nowadays,the development of mobile communications is rapidly gaining momentum.4G communications has matured and 5G communications have long been on the agenda.Moreover,the smart wearable devices have mushroomed.Wearable antenna is also a research hotspot.In order to meet the trend of development,this thesis focuses on some types of antennas that may be applied in future mobile intelligent terminals,including wearable antenna for wearable terminals,millimeter wave antenna unit and array for 5G applications.Firstly,this thesis has proposed a multi-band watchband antenna based on flexible material.The proposed antenna utilizes multi-stub monopole to generate multi-band performance,and employs high order mode and coupling stubs to produce more resonant bands.We have studied the performances of the proposed flexible antenna under flat and bend conditions,respectively.We have designed a human arm model,and compared the performances of the flexible antenna with the human arm model,under bend and flat states.In states of flat and bend,simulated and measured results show that the-6dB reflection coefficient bandwidth of this multi-band flexible watchband antenna are both approximately coverage GSM 1800 MHz band,the ISM 2400 MHz band,Bluetooth band,WiMAX-3500 MHz band and 3.3-3.6 GHz band for future Chinese 5G communication,WLAN-5 GHz band.Moreover,the influence of human tissue on the proposed antenna is within an acceptable range.The proposes flexible multi-band watchband antenna can be employed as an alternative antenna to smart wearable devices.Secondly,this thesis has proposed a broadband millimeter-wave antenna array which may be suitable for future 5G communication.The resonant bandwidth is expanded by etching the slots in the suitable positions of a plane monopolar antenna.Simulated and measured results show that the antenna unit has a resonant bandwidth of 31.3-45.7 GHz and a relative bandwidth of 37.4%.This frequency band covers 4 millimeter-wave bands of 31.8-33.4 GHz,37-40.5 GHz,40.5-42.5 GHz,and 42.5-43.5 GHz,which may be used for future 5G communications.By analyzing the radiation performances of the antenna,a suitable array arrangement manner is selected according to its maximum radiation direction.The vertical array manner is employed to perform phased array simulation analysis.Simulated results show that this antenna array can achieve wide-angle and wide lobe beam scanning performances.The proposed antenna unit and array can be adopted as an alternative antenna to future 5G intelligent terminals.Finally,this thesis has proposed a multi-beam antenna array for future 5G communications.The antenna unit is a magnetoelectric dipole antenna based on SIW technology,and its operating frequency band covers the future China 5G communication millimeter wave 24.75-27.5 GHz band.In order to facilitate processing and testing,a microstrip line to SIW transitional structure has been designed.The feed network of the antenna array employs a 4×4 Butler matrix.Starting from the various components of the Butler matrix,the Hybrid,Crossover,and two types of phase shifter have been designed.The 4×4 Butler matrix is cascaded with the magnetoelectric dipole antenna array to complete the multi-beam antenna array design.Simulation and test results show that the proposed multi-beam antenna array can achieve half-power beam width coverage of ±54° angle domain in azimuth plane in the 24.75-27.5 GHz band.The proposed multi-beam antenna array can be chosen as an alternative antenna to future 5G mobile terminals. |
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