Research And Design Of Highly Integrated Feeding Network System Applied In 5G Massive MIMO Antennas

Massive MIMO antenna arrays are the mainstream form of 5G(5th generation mobile communication)network macro coverage.Typically,up to 192 radiating units are used to form 64TR(3 units combined into a sub-array)to meet the electrical performance requirements of network coverage.However,the excessive number of 64 transceiver channels has brought about the cost and size of the main base station equipment,as well as the power consumption and heat dissipation in long-term applications,even has affected the application process of 5G.By introducing the phase shifter to simplify it to 32 TR,and moving the32-way filters from the main device side to the antenna side,the above problems will be resolved.Therefore,it is difficult to design and has practical significance to study a 32 TR miniaturized highly integrated feeding network applied in massive MIMO antennas to achieve electrical performance equivalent to the 64 TR system,which has the functions of phase shifting and filtering.In this thesis,the research status and design principle of active integrated large-scale antennas and the key components of its feeding network,which contain phase shifter and dielectric filter,are briefly described.Then according to the design requirements,the layout of the feeding network system is formulated.Among the 5G frequency range from 3.4GHz to3.6GHz,this thesis researches and designs the phase shifter and filter integrated in the feeding network.Firstly,this thesis analyzes the characteristics and applicability of various phase shifters,then coupled line sliding phase shifter is selected as the design type.According to the principle of miniaturization,a U-shape phase shifter with low profile and small volume is proposed in this thesis,which can achieve the phase shift of 158° within 15 mm slide stroke.A method of eliminating the cavity resonance without increasing the external size of the cavity is also proposed.At the same time,a ceramic-filled dielectric waveguide bandpass filter is proposed by using the modern synthetical filter design method.The transmission zeros are introduced by setting up the cross coupling structure,which realizes the miniaturization with 50 d B out band suppression.The designed filter has stable performance,compact size,and can be attached to the feeding network PCB boards,which is practical.In this thesis,the integrated feeding network,including phase shifter and dielectric waveguide filter,has been designed and manufactured.All the test indicators meet the design requirements.Finally,the complete feeding network system is applied to a 32 TR dual-polarized Massive MIMO antenna prototype.The measured results are as follows: the overall VSWR is less than 1.5 among the frequency range from 3.4GHz to 3.6GHz;the average gain is 23.2d Bi during the beam downtilt range from 2°to12°;the error of downtilt is less than 1°;the sidelobe suppression is better than 15 d B.Compared with 64 TR antenna array,the 32 TR phase-shifting and filtering integrated feeding network system proposed in this thesis not only meets the requirements of antenna electrical performance coverage,but also has advantages in size and cost as well as the power consumption and heat dissipation in long-term application.The corresponding product has been mass-produced and put on the market,which has a good application prospect.